iphone and gis development notes

Rails Note #14: QuickStart Tutorial

rupert — Sun, 07 Feb 2010 05:39:31 +0000

If you haven’t installed ruby, follow this post

Part 1: Installation and Configuration (Rails and Passenger)

1. Upgrade existing ruby gems

sudo gem list
sudo gem update --system

UPDATE: Took me 4 hours figuring this out. There was a problem when i run script/console that it will say the “gem” detected was 1.0.1 although the current gem version is 1.3.5 after gem update –system. Google didn’t helped out. But I was able to nail down the problem from this post:

https://wincent.com/wiki/Upgrading_to_RubyGems_1.0.1_on_Mac_OS_X_10.5.1
In the post above, notice that rubygems 1.0.1 was installed in /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin. I guess this gem was being referenced first before the actual /usr/local/bin/gem. So I deleted this directory /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr.

Possible sources of gem installations:

/Users/rupert/.gem/ruby/1.8/gems
/Library/Ruby/Gems/1.8/gems

rupert:1.8 rupert$ gem env
RubyGems Environment:
  - RUBYGEMS VERSION: 1.3.5
  - RUBY VERSION: 1.8.6 (2008-08-08 patchlevel 286) [i686-darwin9.5.0]
  - INSTALLATION DIRECTORY: /usr/local/lib/ruby/gems/1.8
  - RUBY EXECUTABLE: /usr/local/bin/ruby
  - EXECUTABLE DIRECTORY: /usr/local/bin
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86-darwin-9
  - GEM PATHS:
     - /usr/local/lib/ruby/gems/1.8
     - /Users/rupert/.gem/ruby/1.8
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - http://gems.rubyforge.org/

2. Install rails. Download from ruby-forge. Link?

gem install -V rails-2.3.3.gem
gem install -V mysql

3. Install and configure passenger for Apache2

gem install -V passenger
cd /Users/rupert/.gem/ruby/1.8/gems/passenger-2.2.5/bin
passenger-install-apache2-module

469 LoadModule passenger_module /Users/rupert/.gem/ruby/1.8/gems/passenger-2.2.5/ext/apache2/mod_passenger.so
470 PassengerRoot /Users/rupert/.gem/ruby/1.8/gems/passenger-2.2.5
471 PassengerRuby /usr/local/bin/ruby
472 
473 
474   RailsBaseURI /rails/travelsiteph
475

4. Create a sample rails project (”travelsiteph”) in your project directory (”/Users/rupert/projects/rails”).

$ cd /Users/rupert/projects/rails
$ rails travelisteph
      create  
      create  app/controllers
      create  app/helpers
      create  app/models
      create  app/views/layouts
      create  config/environments
	.....
$ ls -la travelsiteph
drwxr-xr-x  15 rupert  admin    510  2 Sep 21:14 .
drwxr-xr-x   5 rupert  admin    170 30 Sep 16:31 ..
-rw-r--r--   1 rupert  admin  10011  2 Sep 21:14 README
-rw-r--r--   1 rupert  admin    307  2 Sep 21:14 Rakefile
drwxr-xr-x   6 rupert  admin    204  2 Sep 21:14 app
drwxr-xr-x   9 rupert  admin    306  2 Sep 21:14 config
drwxr-xr-x   4 rupert  admin    136  2 Sep 21:18 db
drwxr-xr-x   3 rupert  admin    102  2 Sep 21:14 doc
drwxr-xr-x   3 rupert  admin    102  2 Sep 21:14 lib
drwxr-xr-x   6 rupert  admin    204  2 Sep 21:14 log
drwxr-xr-x  11 rupert  admin    374  2 Sep 21:14 public
drwxr-xr-x  11 rupert  admin    374  2 Sep 21:14 script
drwxr-xr-x   8 rupert  admin    272  2 Sep 21:55 test
drwxr-xr-x   6 rupert  admin    204  2 Sep 22:07 tmp
drwxr-xr-x   3 rupert  admin    102  2 Sep 21:14 vendor

I have /wwwroot as my document WebRoot. Its running cf, php and mapserv (cgi-bin). Since I want to mix it with rails development, I’ll just make a rails subdirectory. Inside the rails subdirectory, I can create symbolic links to my rails applications located in my projects directory. This way, rails configuration is not exposed from Apache.

cd /wwwroot
mkdir rails
ln -s /Users/rupert/projects/rails/travelsiteph/public travelsiteph
 
$ ls -la
total 8
drwxr-xr-x   3 rupert  admin   102  2 Sep 14:09 .
drwxrwxr-x  60 root    admin  2040  2 Sep 14:08 ..
lrwxr-xr-x   1 rupert  admin    42  2 Sep 14:09 travelsiteph -> /Users/rupert/projects/rails/travelsiteph/public

5. Restart Apache to take the new configuration

sudo /Library/StartupItems/Apache2/Apache2 restart

6. Open http://127.0.0.1/rails/travelsiteph/

But for development purposes, it is better to use http://127.0.0.1:3000/ to see immediately any changes in code.

Part 2: Rails Development
MySQL Prerequisites:

GRANT ALL PRIVILEGES ON *.* TO rupert@'%' IDENTIFIED BY '*************' WITH GRANT OPTION;
$ mysql -u rupert -p

1. Create three databases:

mysql> CREATE DATABASE travelsiteph_development;
Query OK, 1 row affected (0.00 sec)
 
mysql> CREATE DATABASE travelsiteph_test;
Query OK, 1 row affected (0.00 sec)
 
mysql> CREATE DATABASE travelsiteph_deployment;
Query OK, 1 row affected (0.00 sec)

2. Launch Textmate

cd /Users/rupert/projects/rails/travelsiteph
mate .

3. Edit database.yml

development:
  adapter: mysql
  database: travelsiteph_development
  username: root
  password: xxxxxxx
  host: localhost
 
test:
  adapter: mysql
  database: travelsiteph_test
  username: root
  password: xxxxxxx
  host: localhost
 
production:
  adapter: mysql
  database: travelsiteph_deployment
  username: root
  password: xxxxxxx
  host: localhost

4. Generate a Poi model. The model should be capitalized and singular.

$ ruby script/generate model Poi
      exists  app/models/
      exists  test/unit/
      exists  test/fixtures/
      create  app/models/poi.rb
      create  test/unit/poi_test.rb
      create  test/fixtures/pois.yml
      create  db/migrate
      create  db/migrate/20090902111538_create_pois.rb

5. Now let’s create the database table for Poi using migrations.

class Poi < ActiveRecord::Migration
  def self.up
    create_table :pois, :id => :poi_id do |t|
      t.column :name, :string
      t.column :full_address, :string
      t.column :location, :string
      t.column :get_there, :string
      t.column :short_description, :string
      t.column :full_description, :text
      t.column :other_info, :text
      t.column :tel_no, :string
      t.column :fax_no, :string
      t.column :mobile_no, :string
      t.column :email, :string
      t.column :website, :string
      t.column :other_contact_details, :text
      t.column :longitude, :decimal, :precision => 10, :scale => 7
      t.column :latitude, :decimal, :precision => 10, :scale => 7
      t.column :created_at, :timestamp
      t.column :updated_at, :timestamp
      t.timestamps
    end
  end
 
  def self.down
    drop_table :pois
  end
end

$ rake db:migrate
(in /Users/rupert/projects/rails/travelsiteph)
==  CreatePois: migrating =========================================
-- create_table(:point_of_interests, {:id=>:poi_id})
   -> 0.0353s
==  CreatePois: migrated (0.0362s) ================================

6. Generate a Poi controller.

$ script/generate controller Poi
      exists  app/controllers/
      exists  app/helpers/
      create  app/views/poi
      create  test/functional/
      create  test/unit/helpers/
      create  app/controllers/poi_controller.rb
      create  test/functional/poi_controller_test.rb
      create  app/helpers/poi_helper.rb
      create  test/unit/helpers/poi_helper_test.rb

7. Add a list function to Poi Controller

class PoiController < ApplicationController
  def list
    @pois = Poi.find(:all)
  end
end

8. Lets test. Open a browser and point to http://127.0.0.1:3000/travelsiteph/poi/list

$ruby script/server

9. Now create the view list.rhtml in views/poi/

<% if @pois.blank? %>
 
	There are currently no pois in the system. 
 
<% else %>
 
	These are the pois in the system: 
 
	
		<% @pois.each do |poi| %>
			<%= link_to poi.name, {:action => 'show', :id => poi.id} -%>
		<% end %>
	
 
<% end %>

Part 3: Deploying
1. set RAILS_ENV to production

export RAILS_ENV=production

2. Make sure to populate the database in production mode, run rake db:migrate

3. Capistrano

set :port, 2210
set :application, "halalan2010"
#set :repository,  "svn+ssh://2rmobile.com/data/repos/web/rails/halalan2010/"
set :repository,  "http://2rmobile.com/repos/web/rails/halalan2010/"
 
set :scm, :subversion
set :scm_username, 'rupert'
set :scm_password, proc{Capistrano::CLI.password_prompt('SVN pass:')}
# Or: `accurev`, `bzr`, `cvs`, `darcs`, `git`, `mercurial`, `perforce`, `subversion` or `none`
 
role :web, "2rmobile.com" # IP Your HTTP server, Apache/etc
role :app, "2rmobile.com" # This may be the same as your `Web` server
role :db,  "2rmobile.com", :primary => true # This is where Rails migrations will run
#role :db,  "your slave db-server here"
 
set :user,  "rupert"
set :runner, "rupert"
set :deploy_to, "/opt/rails/#{application}"
 
# If you are using Passenger mod_rails uncomment this:
# if you're still using the script/reapear helper you will need
# these http://github.com/rails/irs_process_scripts
 
namespace :deploy do
  task :start do
    run "/etc/init.d/apache2 start"
  end
  task :stop do
    run "/etc/init.d/apache2 stop"
  end
  task :restart, :roles => :app, :except => { :no_release => true } do
     run "#{try_sudo} touch #{File.join(current_path,'tmp','restart.txt')}"
  end
  task :production do
    run "export RAILS_ENV=production"
  end
end
 
namespace :db do
  task :seed do
    run "cd #{deploy_to}/current && RAILS_ENV=production rake db:seed"
  end
  task :populate do
    run "cd #{deploy_to}/current && RAILS_ENV=production rake db:populate"
  end
end

Capistrano commands I normally use:

#on local
#cap deploy:setup
 
#on remote and change owner and permissions of project
sudo chown -Rf rupert:root halalan2010
 
#on local
#cap deploy
#cap db:seed
#cap db:populate

Part 4: Miscellaneous

1. Get a description or rake commands

rake -D db

2. How to populate the database in production mode?

rupert:halalan2010 rupert$ export RAILS_ENV=production
rupert:halalan2010 rupert$ rake db:migrate
(in /Users/rupert/projects/rails/halalan2010)
==  CreateDatabase: migrating =================================================
-- create_table(:candidates)
   -> 0.0036s
-- create_table(:voters)
   -> 0.0031s
-- create_table(:votes)
   -> 0.0027s
==  CreateDatabase: migrated (0.0100s) ========================================

http://blog.airbladesoftware.com/2009/4/10/avoid-typing-rails_env-all-the-time

3. Uninstall specific gem version

gem uninstall activesupport -v 2.2.2

4 Add a source to gem

rupert:rails rupert$ sudo gem sources -a http://gems.github.com
http://gems.github.com added to sources

5. Adding a rails project in svn

#create a remote dir
svn mkdir http://www.2rmobile.com/repos/web/rails/virginmobilechecker
 
#checkout and copy all files
cd ~/projects/rails
mv virginmobilechecker virginmobilechecker_old
svn co "svn+ssh://2rmobile.com/data/repos/web/rails/virginmobilechecker" virginmobilechecker
mv virginmobilechecker_old/* virginmobilechecker/
cd virginmobilechecker
svn add *
 
#ignoring log files
svn revert log/*
svn propset svn:ignore "*.log" log
svn propset svn:ignore "*" tmp
svn propset svn:ignore "*" doc
 
#commit the files
svn commit -m "first commit" *

iPhone Note #20:Integrating Mapserver/TileCache to RouteMe

rupert — Thu, 14 Jan 2010 01:37:57 +0000

Below is a summary of how I was able to implement Mapserver, TileCache and Route-Me iPhone Mapping Framework.

1. Assuming you have a working Mapserver/TileCache setup. Take note of the ff parameters: resolution and bbox. Below is my tilecache.cfg:

 61 [mapserver_australia_3857]
 62 type=MapServerLayer
 63 mapfile=/Users/rupert/projects/pelicancorp/DMOB/trunk/map/australia_3857.map
 64 layers=all
 65 extension=jpg
 66 bbox=-20037508.34, -20037508.34, 20037508.34, 20037508.34
 68 maxResolution=156543.033928041
 70 levels=20
 71 srs=EPSG:3857
 72 tms_type=google
 73 extent_type=loose
 74 spherical_mercator=true

2. Grab the RMGenericMercatorWMSSource from http://groups.google.com/group/route-me-map/browse_thread/thread/b58fa1d20cf15823/e30c42d9c90a8170?lnk=gst&q=Generic#e30c42d9c90a8170

3. By default without any changes, the RMGenericMercatorWMSSource could display Mapserver WMS Tiles. This is possible by passing an NSDictionary *parameters, which contains arrayValues and arrayKeys for creating an http 256×256 image request to the http://127.0.0.1/cgi-bin/mapserv binary.

//This would request to http://127.0.0.1/cgi-bin/mapserv
NSArray *arrayValues = [[NSArray alloc] initWithObjects:@"/path-to/australia_3857.map", @"all", @"png", @"EPSG:3857",nil];
NSArray *arrayKeys = [[NSArray alloc] initWithObjects:@"MAP", @"LAYERS", @"FORMAT", @"SRS", nil];
NSDictionary *wmsParameters = [[NSDictionary alloc] initWithObjects: arrayValues forKeys:arrayKeys ];

Resulting http requests to the mapserv binary:

http://192.168.1.193:81/tilecache/tilecache.py?LAYERS=australia_3857&SRS=EPSG:3857&REQUEST=GetMap&SERVICE=WMS&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&FORMAT=png&VERSION=1.1.1&WIDTH=256&HEIGHT=256&BBOX=16828376.000000,-4006523.000000,16833268.000000,-4001631.000000

Note that the bbox values does not contain decimal places. Nevertheless, it still works on Mapserver.

4. Now, assuming we have a valid tilecache running. And it is tested from browser, i.e http://127.0.0.1/map/tilecache_3857.html, open up firebug to see the requests. Below is a sample…

http://192.168.1.193:81/tilecache/tilecache.py?LAYERS=australia_3857&FORMAT=jpg&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&SRS=EPSG%3A3857&BBOX=16123932.497377,-4539747.9811239,16143500.376618,-4520180.1018829&WIDTH=256&HEIGHT=256

But it seems, route-me is not supplying the bbox values accurately, as the decimal values is truncated (BBOX=16828376.000000,-4006523.000000,16833268.000000,-4001631.000000) from our previous request(3).

After changing the wmsParameter values to create a tilecache request, I noticed that route-me is not displaying the tiles correctly.

//Testing for Windows:TileCache - ?
NSArray *arrayValues = [[NSArray alloc] initWithObjects:@"australia_3857", @"png", @"EPSG:3857",nil]; //for WIndows
 
//TileCache URL Parameters:
NSArray *arrayKeys = [[NSArray alloc] initWithObjects:@"LAYERS", @"FORMAT", @"SRS", nil];

5. The workaround is to use “double” instead of “floats” in the RMGenericMercatorWMSSource. You can download the zip from RMGenericMercatorWMSSource.zip. I have modified “initialResolution” and “originShift” to both use “double”.

typedef struct {
	double x;
	double y;
} CGDoublePoint;
 
typedef struct { 
	CGDoublePoint ul; 
	CGDoublePoint lr; 
} CGXYRect;

Afterwards, I copied the maxResolution and bbox (tilecache) and specified it for the initialResoultion and originShift respectively.

#import "RMGenericMercatorWMSSource.h"
 
CGFloat DegreesToRadians(CGFloat degrees) {return degrees * M_PI / 180;}; 
CGFloat RadiansToDegrees(CGFloat radians) {return radians * 180/ M_PI;}; 
 
@implementation RMGenericMercatorWMSSource
 
-(id) initWithBaseUrl:(NSString *)baseUrl parameters:(NSDictionary *)params
{ 
	if (![super init]) 
		return nil; 
 
	// 156543.03392804062 for sideLength 256 pixels 
	// initialResolution = 2 * M_PI * 6378137 / [self tileSideLength];
	// specify here whatever the resolution is from tilecache.
	initialResolution = 156543.033928041;
 
	// 20037508.342789244 
	//originShift = 2 * M_PI * 6378137 / 2;
	//originShift = 20037508.342789244f;
	// specify here whatever the bbox is from tilecache.
	originShift = 20037508.32;
 
	NSLog(@"test initialResolution:%f originShift:%f", initialResolution, originShift);
 
	// setup default parameters
	// use official EPSG:3857 by default, user can override to 900913 if needed.
	wmsParameters = [[NSMutableDictionary alloc] initWithObjects:[[[NSArray alloc] initWithObjects:@"EPSG:3857",@"image/png",@"GetMap",@"1.1.1",@"WMS",nil] autorelease] 
											  forKeys:[[[NSArray alloc] initWithObjects:@"SRS",@"FORMAT",@"REQUEST",@"VERSION",@"SERVICE",nil] autorelease]];
	[wmsParameters addEntriesFromDictionary:params];
 
	// build WMS request URL template
	urlTemplate = [NSString stringWithString:baseUrl];
	NSEnumerator *e = [wmsParameters keyEnumerator];
	NSString *key;
	NSString *delimiter = @"";
	while (key = [e nextObject]) {
		urlTemplate = [urlTemplate stringByAppendingFormat:@"%@%@=%@",
					   delimiter,
					   [[key uppercaseString] stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding], 
					   [[wmsParameters objectForKey:key] stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding]];
		delimiter = @"&";
	}
	int sideLength =  [self tileSideLength];
	urlTemplate = [[urlTemplate stringByAppendingFormat:@"&WIDTH=%d&HEIGHT=%d",sideLength,sideLength] retain];
	return self;
}
 
// implement in subclass?
-(NSString*) uniqueTilecacheKey
{
	return @"AbstractMercatorWMSSource";
}
 
-(NSString *)shortName
{
	return @"Generic WMS Source";
}
-(NSString *)longDescription
{
	return @"Generic WMS Source";
}
-(NSString *)shortAttribution
{
	return @"Generic WMS Source";
}
-(NSString *)longAttribution
{
	return @"Generic WMS Source";
}
 
-(float) minZoom
{
	return 1.0f;
}
-(float) maxZoom
{
	return 19.0f;
}
 
// Converts given lat/lon in WGS84 Datum to XY in Spherical Mercator EPSG:3857 
-(CGPoint) LatLonToMeters: (CLLocationCoordinate2D) latlon 
{ 
	CGPoint meters; 
	meters.x = latlon.longitude * originShift / 180; 
	meters.y = (log( tan((90.0 + latlon.latitude) * M_PI / 360.0 )) / (M_PI / 180.0)) * originShift / 180; 
	return meters; 
}
 
//Converts XY point from Spherical Mercator EPSG:3857 to lat/lon in WGS84 Datum 
-(CLLocationCoordinate2D) MetersToLatLon: (CGPoint) meters 
{ 
	CLLocationCoordinate2D latlon; 
	latlon.longitude = (meters.x / originShift) * 180.0; 
	latlon.latitude = (meters.y / originShift) * 180.0; 
	//latlon.latitude = - 180 / M_PI * (2 * atan( exp( latlon.latitude * M_PI / 180.0)) - M_PI / 2.0); 
	latlon.latitude = 180 / M_PI * (2 * atan( exp( latlon.latitude * M_PI / 180.0)) - M_PI / 2.0); 
	return latlon; 
} 
 
// Converts pixel coordinates in given zoom level of pyramid to EPSG:3857 
-(CGDoublePoint) PixelsToMeters: (int) px PixelY:(int)py atZoom:(int)zoom 
{ 
	double resolution = [self ResolutionAtZoom: zoom]; 
	CGDoublePoint meters; 
	double x = (px * resolution - originShift); 
	double y = (py * resolution - originShift); 
 
	meters.x = x;
	meters.y = y;
 
	NSLog(@"px: %d py: %d resolution: %f originShift: %f x: %f y: %f", px, py, resolution, originShift, x, y);
 
	return meters; 
} 
 
-(NSString*) tileURL: (RMTile) tile 
{ 
	//RMLatLongBounds tileBounds = [self TileLatLonBounds:tile];
	// Get BBOX coordinates in meters
	CGXYRect tileBounds = [self TileBounds:tile];
 
	NSString *url = [urlTemplate stringByAppendingFormat:@"&BBOX=%f,%f,%f,%f",
					 tileBounds.ul.x,
					 tileBounds.lr.y,
					 tileBounds.lr.x,
					 tileBounds.ul.y];
 
	NSLog(@"Tile %d,%d,%d yields %@",tile.zoom, tile.x, tile.y, url); 
 
	return url; 
} 
 
 
//Returns bounds of the given tile in EPSG:3857 coordinates 
-(CGXYRect)  TileBounds: (RMTile) tile 
{
	int sideLength =  [self tileSideLength];
 
	int zoom = tile.zoom;
	long twoToZoom = pow(2,zoom);
	CGXYRect tileBounds; 
	tileBounds.ul = [self PixelsToMeters: (tile.x * sideLength) 
								  PixelY: ((twoToZoom-tile.y) * sideLength) 
								  atZoom: zoom ]; 
	tileBounds.lr = [self PixelsToMeters: ((tile.x+1) * sideLength) 
								  PixelY: ((twoToZoom-tile.y-1) * sideLength) 
								  atZoom: zoom];
	return tileBounds; 
} 
 
//Resolution (meters/pixel) for given zoom level (measured at Equator) 
-(double) ResolutionAtZoom : (int) zoom 
{ 
	return initialResolution / pow(2,zoom); 
} 
 
@end

6. Download TileCache_RouteMe.zip Note: You need a valid mapserver and tilecache running.

iPhone Note #19: Route-Me: Opensource mapping for the iphone

rupert — Tue, 08 Dec 2009 05:34:51 +0000

Route-Me is an opensource mapping api similar to the MapKit.framework. The main project resides in googlecode (http://code.google.com/p/route-me/).

Part 1: Making the Sample Apps work.

1. Download the code from svn.
svn co http://route-me.googlecode.com/svn/trunk/ route-me

2. In the route-me directory, you would have 3 directories:
- MapView – this contains the mapping framework
- Proj4 – projection library.
- samples

3. Build MapView. I encountered some problems here, particularly this specific issue: Cannot build on 3.1 using iphone simulator.

How to make the build? Now, at the time of this writing, I have XCode3.1.4 and iPhone 3.0, 3.1, 3.1.2. Edit the project settings so that the “build” and “release” will point to use 3.0. If you encounter a problem, it is best to “Clean All”, remove the build directory, then “Build” again. To verfiy if you have a successful build, notice that libMapView.a was created.

Note: Notice here that I have libMapView.a both in Debug-iphoneos/ and Debug-iphonesimulator/

No need to build Proj4 as long as it is sitting on the same directory where MapView is.

4. To test route-me, we can study from the samples directory. Let’s build samples/SampleMap. Notice that SampleMap has a reference to MapView.xcodeproj.

Similarly, we can build this using 3.0 both in the simulator and device.

Part 2: Integrating with your own project.

Reference: http://code.google.com/p/route-me/wiki/EmbeddingGuide

1. Create a view-based project: MyRMSampleMap.

2. Project -> “Add To Project”. Make the reference type as “Relative to Project”.

3. Configure your project to have a direct dependency with MapView.xcodeproj. Follow the instructions exactly as stated from the EmbeddingGuide.

Click on the “Build” tab in your target’s info window.

Change the Configuration popup to read “All Configurations”, so that your changes can be made just once.

Find “Header Search Paths” under “Search Paths” (shortcut: type “header” in the search box at upper right of the target info window). Double-click on the ‘Header Search Paths’ text and add the path to the MapView directory contained in the route-me project located on your file system. (Note that if there are any spaces in the path, enclose the entire entry with “”. If the MapView project folder is placed next to your project’s project folder on the file system, you would have the following in the path: “../MapView”.

Check the ‘Recursive’ box and click Ok.

4. Make a test “Build”.

5. Add a reference to:
- QuartzCore.framework
- libsqlite3.dylib

6. Let’s add our mapview in the interface: MyRMSampleMapViewController.h

#import 
#import "RMMapView.h"
 
@interface MyRMSampleMapViewController : UIViewController {
	RMMapView *mapview;
}
 
@property(nonatomic, retain) RMMapView *mapview;
 
@end

7. In the implementation, add this snippet.

@synthesize mapview;
...
- (void)viewWillAppear:(BOOL)animated{
	mapview = [[RMMapView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 460.0f)];
	[mapview setBackgroundColor:[UIColor blackColor]];
 
	[self.view addSubview:mapview];
}

Download: MyRMSampleMap.zip

iPhone Note #18: Integrating Ads (AdMob) on your iPhone App

rupert — Mon, 07 Dec 2009 00:46:39 +0000

Basic Info

What is common with these ad platforms?
Each application is offered a unique id which needs to be specified during development.

What is publishing?
Publishing allows the developer to display (publish) ads on the native application.

What is CPM?
Impressions per thousand. Normally ad networks pays $1 for every 1000 CPM. So you need 1000 page views (not clicks) to earn a buck.

What is the fillrate?
The percentage of impressions served based on total requests for ads. This is number to look for when you get blank ads. How many of my clients gets an ad impression? I had 60%

What is the Click Through Rate (CTR)?
Out of 60% of my clients who had ad impressions, 6.18% of them clicked the ad. The more they get clicked, the higher your revenue.

Admob

Offers both publishing and analytics. Currently offers both iPhone and Android. Able to publish ads for native app and mobile websites. This is my preferred ad network of choice as it is easier to setup than the others. And just recently, it was swallowed by Google, whether that is good or bad for us, we have yet to know.

AdMob Iphone SDK Integration

1. After signing up/registering to Admob you need to add your application in “Sites & Apps” tab (2nd tab from the left).

2. Click on “Add Site/App” and you would be presented with what kind of site or app type (Mobile Web, Iphone App, Iphone Web and Android App). Select “Iphone App” and fill out the details..

3. If you go to “Sites & Apps”, there’s a link “Setup” just under the Quick Links. You could download a sample AdMob application there wherein your publisherId is already built-in. Here’s a sample (admob_iphone_sdk_20091119.tar.gz). Note that AdMob upgrade their code, notice the dates (20091119)? So it’s good practice to read the CHANGELOG.

4. Note your publisherId.

#pragma mark Admob delegate methods
- (NSString *)publisherId {
	return @"a14ac98028663b0"; // bayanihan
}

5. Make the sample application from AdMob run first before integrating your app.

// To receive test ads rather than real ads...
- (BOOL)useTestAd {
	return YES; //change this to NO later..
}

6. Normally, the problems/quirks I experience when integrating a 3rd Party Project are framework references. So, here’s mine:

Note: As of ver 20091119, I added MessageUI.framework, AudioToolbox.framework, MediaPlayer.framework. Prior to that build (200906xx), I don’t have those. If you are compiling against iPhoneOS version 3, then you would need to reference libAdMObDevice3_0.a and libAdMobSimulator3_0.a (to run it in the simulator–but you would take this reference off when making an actual build)

7. Now, that both the testAd (YES) is working, it might take you a few hours before the real ad comes in. Be patient. :)

8. Integrate to your project. AdMob provided detailed examples on how to integrate depending on your needs–Interface Builder (IB), Programmatically or TableView. Personally, I have used both IB and TableView and it works flawlessly.

9. I dont get an ad? I get an Ad? Which one? Check out the AdMobDelegate Methods.

- (void)didReceiveAd:(AdMobView *)adView {
	NSLog(@"AdMob: Did receive ad");
}
 
- (void)didFailToReceiveAd:(AdMobView *)adView {
	NSLog(@"AdMob: Did fail to receive ad");
 
	//[self createMobclix];
	//[bannerCell setNeedsLayout];
}

10. Now once you have AdMob going, you want to be more efficient and get higher fill rates. You can checkout other Ad Platforms (Mobclix, Adwhirl). Notice on step 9 above, that if I don’t get an ad from AdMob, I fire up an add from MobClix.

iPhone Note #17: Displaying a custom view controller from a UITextField

rupert — Mon, 02 Nov 2009 00:49:56 +0000

Problem: I want my textFieldSearchAddress to display a seperate viewcontroller.

Short Answer: Hide the keyboard by using

[textField resignFirstResponder]

then show the view controller.

1. Implement a UITextFieldDelegate.

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField{
	[textField resignFirstResponder];
	[self show];
	return NO;
}

Be careful with the BOOL return of textFieldShouldBeginEditing. From the docs: “YES if an editing session should be initiated; otherwise, NO to disallow editing.”

2. Show the view controller.

- (IBAction)show{
	NSLog(@"show");
 
	AddressViewController *addressViewController = [[AddressViewController alloc] initWithNibName:@"AddressViewController" bundle:nil];
	UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:addressViewController];
	[self presentModalViewController:nav animated:YES];
 
	[addressViewController release];
	[nav release];
 
}

Download SimpleIB-textfield_custom_view_controller.zip

Subversion

rupert — Sat, 31 Oct 2009 22:22:01 +0000

This post will contain a summary of information regarding subversion scattered from old posts.

Installation on Debian

1. Packages

#apt-get install subversion
#apt-get install libapache2-svn

2. Login as root then create the repository.

#cd /data
#svnadmin create /repos --fs-type fsfs

3. Set the permissions

#groupadd subversion
#addgroup rupert subversion
#addgroup www-data subversion
 
#chown -Rf www-data:subversion /data/repos
#chmod -Rf 770 repos

It’s better to set the necessary users and groups that would use subversion now. Later on, if we need to checkout using svn+ssh and setup a passwordless svn, then we won’t get permission issues.

4. In /etc/apache2/sites-available/2rmobile, add this to the configuration.

        
        DAV svn
        SVNPath /data/repos
        SVNAutoversioning on
        AuthType Basic
        AuthName "SVN - Your Project"
        AuthUserFile /data/svn-auth-file
        Require valid-user

5. Enable the webdav module then restart apache.

#a2enmod dav
#a2enmod dav_svn
#/etc/init.d/apache2 restart

Passwordless SVN

On your local macbook pro (mbp), we need to generate the ssh keys from the local machine, upload it to the remote machine and append it in the authorized_keys.

On the local machine:

#ssh-keygen -t rsa
...
#cd /Users/rupert/.ssh
#scp -r id_rsa.pub rupert@2rmobile.com:/home/rupert/.ssh/id_rsa_mbp.pub

On the remote machine:

#cd ~/.ssh
#touch authorized_keys
#cat id_rsa_mbp.pub >> authorized_keys

Test on the local machine by doing

ssh rupert@2rmobile.com

. In my mbp, a dialog box from keychain is asking for the password. To circumvent this, we can add the passphrase to our identities.

#ssh-add -K
... enter the passphrase twice...
#ssh-add -k (adds it to the identities)
#ssh-add -l (lists the identities)

Now the benefits of having a passwordless svn:
- ofcourse it saves us a lot of time
- rails capistrano deployment

References:
http://www.howtoforge.com/debian_subversion_websvn

Subversion Tips and Tricks

http://subversion.tigris.org/faq.html#ssh-authorized-keys-trick

1. Checking out using svn+ssh and having passwordless ssh authentication. My personal favorite when working with personal projects since I have full control.

svn co svn+ssh://www.2rmobile.com/data/repos/web/rails/halalan2010 halalan2010

But for work projects, I normally use webdav

svn co "http://www.2rmobile.com/repos/web/halalan2010" halalan2010

2. svn+ssh on a custom or different port other than 22. I have my ssh on 2210, so we need to tell svn+ssh to use 2210

vim ~/.subversion/config
 41 [tunnels]
 42 ### Configure svn protocol tunnel schemes here.  By default, only
....
 53 ### built-in ssh scheme were not predefined, it could be defined
 54 ### as:
 55 ssh = $SVN_SSH ssh -p 2210

http://www.techper.net/2009/01/11/changing-port-number-of-svnssh-subversion-protocol/

3. svn diff – shows you the changes in a directory. This is useful for creating patches.

svn diff -r HEAD
svn st -q

3. svn switch oldURL to newURL - very useful when I’m working at home or in the office, since the svn server has a public/private IP.

4. svn log – shows you who committed and why (from the messages)

5. ignoring specific files in a directory. i.e rails directories

svn propset svn:ignore "*.log" log

iPhone Note #16: Creating a MKMapView using IB

rupert — Thu, 29 Oct 2009 06:25:59 +0000

In this tutorial we will be addking MKMapView using IB to a ViewController.

1. XCode -> File -> New Project -> View-based Application.

Name the project “SimpleMapIB”

2. Make sure everything works out accordingly before doing anything. Let’s test from the iPhone Simulator. Click on “Build and Go”. You should see the iPhone Simulator running with a gray background. Bring up the Debugger Console (XCode -> Run -> Console) as well and it should be free from errors.

3. Now double-click on “SimpleMapIBViewController.xib”, it should open in Interface Builder.

4. Drag a UIToolbar to the bottom. We will use the button as a GPS in our next tutorial.

5. Drag MKMapView to the middle of the screen.

6. IB -> save

7. Now we need to reference Mapkit. Go to XCode -> Project -> Edit Active Target “SimpleMapIB”. Click the + icon on the bottom left, choose MapKit.framework, then “Add”.

You should see Mapkit added to the frameworks.

You could also organize XCode’s left panel by dragging “MapKit.framework” to the Frameworks Group.

7. Let’s code SimpleMapIBViewController.h

#import 
#import 
 
@interface SimpleMapIBViewController : UIViewController {
	IBOutlet MKMapView *mapview;
}
 
@property(nonatomic, retain) IBOutlet MKMapView *mapview;
 
@end

8. Now back to IB. Click on the “File’s Owner” and you should see your outlets displayed “Connections Inspector”. Drag “mapview” to MKMapView Control.

Note: You can click for a bigger image.

9. Now to set “SimpleMapIBViewController” as the delegate. Click on the MKMapView, it should be highlighted and in the “Connections Inspector” notice the “delegate” come out in the Outlets. Drag it to the “Files Owner” to set “SimpleMapIBViewController” as the delegate.

Note: You can click for a bigger image.

10. Now, let’s test. Hit “Clean All” then “Build and Go”. You should see something like this..

11. Now to test that the delegate is setup accordingly, we can code on the viewDidLoad.

- (void)viewDidLoad {
    mapview.mapType = MKMapTypeSatellite;
 
	[super viewDidLoad];
}

12, Now press command-Y for “Build and Debug”. We should see a satellite map instead.

13. That seems a little bit dull, lets add a segmented control so we can switch between maptypes (standard, satellite, hybrid). In IB, drag a UISegmentedControl in the UIToolbar at the bottom. Add another segment, making a total of three. Then change the titles to “Normal”, “Sat”, “Hybrid” respectively.

Now in IB, click on the “File’s Owner” and you should see your outlets displayed “Connections Inspector”. Drag “segmentedControlMapType” to the segmented control just like what we did for mapview.

14. Let’s code. In the interface, we need to add a method that would be called by the segmentedControl whened the values changed.

#import 
#import 
 
@interface SimpleMapIBViewController : UIViewController {
	IBOutlet MKMapView *mapview;
	IBOutlet UISegmentedControl *segmentedControlMapType;
}
 
@property(nonatomic, retain) IBOutlet MKMapView *mapview;
@property(nonatomic, retain) IBOutlet UISegmentedControl *segmentedControlMapType;
 
- (IBAction)changeMapType: (id)sender;
 
@end

15. In the implementation, we can switch between the segmentIndex and display the corresponding MKMapType.

- (IBAction)changeMapType: (id)sender{
	if(segmentedControlMapType.selectedSegmentIndex == 0){
		mapview.mapType = MKMapTypeStandard;
	}
	else if(segmentedControlMapType.selectedSegmentIndex == 1){
		mapview.mapType = MKMapTypeSatellite;
	}
	else if(segmentedControlMapType.selectedSegmentIndex == 2){
		mapview.mapType = MKMapTypeHybrid;
	}
 
}

16. Now to hook the IBAction of the UISegmentedControl to the method. In IB, click on the segmented control and in the “Connections Inspector”, drag the “Value Changed” Event to the “File’s Owner” and choose “changeMapType”.

Download SimpleMapIB.zip

In my next tutorial, I would be hooking up a GPS button which handles location updates using CoreLocation.

iPhone Note #15: Omnigraffle iPhone Stencils, Screen Mockups via PPT, creating an iPhone interface before actual development

rupert — Mon, 19 Oct 2009 22:41:47 +0000

I can not argue enough how valuable an iphone stencil will be in seeing the overall design/flow of an application. I should have done this a long time ago.

Well, I am also one of those eager developers who dives right into coding and see how it goes. But after having the fundamentals of iphone development, objective-c, and app-store submission, I’m taking on a different approach by creating screen mockups mainly for the following reasons:

1. Reach out quickly to the client.

2. Provides a bird’s eye view of the whole application. Provides alternative screens for a better user experience..

3. A follow up on the screen mockups is a powerpoint with actual links to other slides thus mimicing an iphone interface. Note, it is not a complete replica of the simulator but just enough for decision makers to understand what’s in there.

In powerpoint, you can just quickly overlay a transparent polygon on top of the UIButton then attach a hyperlink to another slide.

Hope this post helps you even if it’s not related to coding. On my next post, which is currently buried in my drafts–hopefully it will not be that long, I learned about integrating with Mobile Advertising Networks.

UPDATED: Bayanihan iPhone Project for Ondoy. Submitted.

rupert — Mon, 05 Oct 2009 05:53:45 +0000

I am a programmer currently in Melbourne, Australia hoping to raise awareness for the victims affected by typhoon Ondoy (Ketsana-international name). Experiencing a flood is not new to me as I was born and raised in Tumana, Marikina, Metro Manila. I was in primary school, when I could vividly remember my mother cooking and serving porridge to typhoon victims as our backyard was called “high ground” since it is near the main road (JP Rizal).

I was in college when Tumana bridge was built and helped me travel from my house to the University. Unfortunately, the river would swell and the flood would swallow the whole bridge after 2-3 days of rain. I called my mother on Sept 27 and was informed the typhoon poured over a whole month of rain in just a few hours! Don’t worry my mother is fine, however, there are those who are unfortunate enough who desperately call for our help. In my small way by making this application, I would like to show my support for them.

I’m almost finished with the Bayanihan iPhone project which I worked on over the weekend. It is a very simple app with scrollable images. The server side is almost finished and would display how many supported/downloaded the application in real time. I am hoping to upload the server side to my Linode hosting in the US asap.

How can you help? I need pictures! Pictures from Tumana would be greatly appreciated, however, if you have other pictures, please do send them as well. I will be bundling 10 pictures inside the application. Please include your name, with subject: BAYANIHAN pix and send the pictures to my email address: rndguzmanjr@gmail.com

Hopefully I can submit the app to Apple within this week or early next week. Afterwards, we wait for the approval process within 2 weeks. Note, the app would be FREE.

UPDATE OCT-05-2009 9:00PM
I took some pictures from facebook and dropped it in the project. It would look something like this when it is finished.

UPDATE OCT-11-2009
- Included proper credits for each photograph.
- Added Admob.
- Created logo, large application icon.

UPDATE OCT-12-2009
Preparing for appstore submission..

UPDATE OCT-13-2009
Submitted in AppStore. Currently, In-Review.

iPhone Note #14: Drawing a Point, Line, Polygon on top of MKMapview

rupert — Fri, 02 Oct 2009 06:00:49 +0000

This is an update to iPhone DevNote #13. This post has solved my zooming/panning problem with a CustomView on top of my MKMapView courtesy of http://spitzkoff.com/craig/?p=108 (Craig’s blog).

The trick here is instead of doing the drawing on the drawRect method of the CustomView, we will use Craig’s methodology to use the drawRect method of a custom MKAnnotationView. Note, that he also used an internal view and made clipsToBounds = NO, this way we can draw the whole geometry on top of MKMapView not just a portion of it. The end result is the shape (polygon in this example) is below the added pins.

@interface LinePolygonAnnotationInternalView : UIView
{
	// line view which added this as a subview. 
	LinePolygonAnnotationView* _mainView;
}
@property (nonatomic, retain) LinePolygonAnnotationView* mainView;
@end
 
@implementation LinePolygonAnnotationInternalView
 
@synthesize mainView = _mainView;
 
-(id) init
{
	self = [super init];
	self.backgroundColor = [UIColor clearColor];
	self.clipsToBounds = NO;
 
	return self;
}
 
 
-(void) drawRect:(CGRect) rect
{
	GeometryAnnotation* myAnnotation = (GeometryAnnotation*)self.mainView.annotation;
 
	// only draw our lines if we're not int he moddie of a transition and we 
	// acutally have some points to draw. 
	if(!self.hidden && nil != myAnnotation.points && myAnnotation.points.count > 0)
	{
		CGContextRef context = UIGraphicsGetCurrentContext(); 
 
		// Drawing lines with a white stroke color
		CGContextSetRGBStrokeColor(context, 1.0, 1.0, 1.0, 1.0);
 
		// Draw them with a 2.0 stroke width so they are a bit more visible.
		CGContextSetLineWidth(context, 2.0);		
 
		if(myAnnotation.geometryType == kGeometryTypePolygon){
			CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1.0);
		}
 
		// Draw them with a 2.0 stroke width so they are a bit more visible.
		CGContextSetLineWidth(context, 2.0);
 
		for(int idx = 0; idx < myAnnotation.points.count; idx++)
		{
			CLLocation* location = [myAnnotation.points objectAtIndex:idx];
			CGPoint point = [self.mainView.mapView convertCoordinate:location.coordinate toPointToView:self];
 
			NSLog(@"Point: %lf, %lf", point.x, point.y);
 
			if(idx == 0)
			{
				// move to the first point
				CGContextMoveToPoint(context, point.x, point.y);
			}
			else
			{
				CGContextAddLineToPoint(context, point.x, point.y);
			}
		}
 
		if(myAnnotation.geometryType == kGeometryTypeLine){
			CGContextStrokePath(context);
		}
		else if(myAnnotation.geometryType == kGeometryTypePolygon){
			CGContextClosePath(context);
 
			CGContextDrawPath(context, kCGPathFillStroke);
		}
 
	}
 
 
}
 
-(void) dealloc
{
	self.mainView = nil;
 
	[super dealloc];
}
@end
 
@implementation LinePolygonAnnotationView
 
@synthesize mapView = _mapView;
 
- (id)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
 
		self.backgroundColor = [UIColor clearColor];
 
		// do not clip the bounds. We need the LinePolygonAnnotationInternalView to be able to render the whole line/polygon, regardless of where the
		// actual annotation view is displayed. 
		self.clipsToBounds = NO;
 
		// create the internal line view that does the rendering of the line. 
		_internalView = [[LinePolygonAnnotationInternalView alloc] init];
		_internalView.mainView = self;
 
		[self addSubview:_internalView];
    }
    return self;
}
 
-(void) setMapView:(MKMapView*) mapView
{
	[_mapView release];
	_mapView = [mapView retain];
 
	[self regionChanged];
}
 
-(void) regionChanged
{
	NSLog(@"Region Changed");
 
	// move the internal line view. 
	CGPoint origin = CGPointMake(0, 0);
	origin = [_mapView convertPoint:origin toView:self];
 
	_internalView.frame = CGRectMake(origin.x, origin.y, _mapView.frame.size.width, _mapView.frame.size.height);
	[_internalView setNeedsDisplay];
 
}
 
- (void)dealloc 
{
	[_mapView release];
	[_internalView release];
 
    [super dealloc];
}
 
 
@end

I extended the class above to be able to draw both lines and polygons by checking a property (geometryType) of the GeometryAnnotation. If the geometryType is a line, then just stroke the path. However, if the geometryType is a polygon, then close the path and fill it.

if(myAnnotation.geometryType == kGeometryTypeLine){
	CGContextStrokePath(context);
}
else if(myAnnotation.geometryType == kGeometryTypePolygon){
	CGContextClosePath(context);
 
	CGContextDrawPath(context, kCGPathFillStroke);
}

And here is the GeometryAnnotation class. Most of the code is from Craig, i just added the geometryType property:

//  Created by Craig on 8/18/09.
//  Copyright Craig Spitzkoff 2009. All rights reserved.
//
 
#import "GeometryAnnotation.h"
 
@implementation GeometryAnnotation
@synthesize coordinate = _center;
@synthesize points = _points; 
@synthesize annotationID;
@synthesize geometryType;
 
-(id) initWithPoints:(NSArray*) points withGeometry:(GeometryType)geomType
{
	self = [super init];
 
	geometryType = geomType;
 
	_points = [[NSMutableArray alloc] initWithArray:points];
 
	// create a unique ID for this line so it can be added to dictionaries by this key. 
	self.annotationID = [NSString stringWithFormat:@"%p", self];
 
 
	// determine a logical center point for this line based on the middle of the lat/lon extents.
	double maxLat = -91;
	double minLat =  91;
	double maxLon = -181;
	double minLon =  181;
 
	for(CLLocation* currentLocation in _points)
	{
		CLLocationCoordinate2D coordinate = currentLocation.coordinate;
 
		if(coordinate.latitude > maxLat)
			maxLat = coordinate.latitude;
		if(coordinate.latitude < minLat)
			minLat = coordinate.latitude;
		if(coordinate.longitude > maxLon)
			maxLon = coordinate.longitude;
		if(coordinate.longitude < minLon)
			minLon = coordinate.longitude; 
	}
 
	_span.latitudeDelta = (maxLat + 90) - (minLat + 90);
	_span.longitudeDelta = (maxLon + 180) - (minLon + 180);
 
	// the center point is the average of the max and mins
	_center.latitude = minLat + _span.latitudeDelta / 2;
	_center.longitude = minLon + _span.longitudeDelta / 2;
 
	NSLog(@"Found center of new Annotation at %lf, %ld", _center.latitude, _center.longitude);
 
	return self;
}
 
-(MKCoordinateRegion) region
{
	MKCoordinateRegion region;
	region.center = _center;
	region.span = _span;
 
	return region;
}
 
-(void) dealloc
{
	[_points release];
 
	[super dealloc];
}
 
@end

Now that we have a way to draw a line/polygon as a custom MKAnnotationView, we need a custom TouchView (GeometryTouchView) which could accept the touch events.

For example, if the user wants to draw a line geometry, the GeometryTouchView would accept touch events from the user and add a point as a PointAnnotation in the Map. Succeeding points would be added to an array. For every point added, the MKAnnotationView drawRects method connects the points to produce a line. The MKAnnotationView is now added to the map.

Once the geometry is added as an annotation, the custom TouchView is hidden. This way we have access (panning/zooming) to the mapview. If we make a pan or a zoom, the region changes, thus we need to redraw the shape of the annotation again.

- (void)mapView:(MKMapView *)mapView regionWillChangeAnimated:(BOOL)animated
{
	if(currentAnnotationView != nil){
		NSLog(@"regionWillChangeAnimated");
 
		currentAnnotationView.hidden = YES;
	}
}
 
- (void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(BOOL)animated
{
	if(currentAnnotationView != nil){
		NSLog(@"regionDidChangeAnimated");
 
		currentAnnotationView.hidden = NO;
		[currentAnnotationView regionChanged];
	}
}

-(void) regionChanged
{
	NSLog(@"Region Changed");
 
	// move the internal line view. 
	CGPoint origin = CGPointMake(0, 0);
	origin = [_mapView convertPoint:origin toView:self];
 
	_internalView.frame = CGRectMake(origin.x, origin.y, _mapView.frame.size.width, _mapView.frame.size.height);
	[_internalView setNeedsDisplay];
 
}

The resulting image is now:

Download the DrawMap.zip code.

iPhone Note #13: Drawing Point, Line, Polygon on top of MKMapview

rupert — Fri, 11 Sep 2009 00:10:36 +0000

Now I have a reason to study Quartz2D! I am trying to draw a point, line and polygon on top of MKMapview. I will list below important links for reference:

1. Always use Apple’s iPhone OS Reference Library Documentation.. Under “Topics” > “Graphics & Animation” you will find a lot of references, guides and sample code.

2. Start out with the Getting Started with Graphics and Animation. Note, if you ever read the line below and try to find Finger Sketch, please drop me a comment. I could not find it anywhere!

“Next, examine the Finger Sketch sample code in Xcode.”

3. iPhone Application Programming Guide: Graphics and Drawing.

4. Note: I haven’t read everything on Quartz 2D Programming Guide, but I went straight to the Paths Section.

5. Lets look at some sample codes, especially the QuartzDemo.

6. Now, I presume you know IB, add a MKMapView and a UIToolbar at the bottom. Add four UIBarButtonItems for: Map, Point, Line, Polygon. Set MKMapView’s delegate to the File’s Owner. Hook up the UIBarButtonItem IBOutlets to your buttons, so we can change the appearance of the buttons when pressed. Lastly, hook up our IBAction methods for each button.

The Map button allows to pan/zoom on the Map. If any of the three geometry buttons (PT, LN, PG) is pressed, we unhide the GeometryView(which is a UIView) to allow touchEvents to proceed.

TO DO: Watch out for this segment as I will update it with code later.

7. Now to draw a line, we implement the code below in our GeometryView.drawRect method. As we loop through each Pin, we add a line to the point. Afterwards, we stroke the path, thus drawing the lines.

CGContextRef context = UIGraphicsGetCurrentContext();
 
// Drawing lines with a white stroke color
CGContextSetRGBStrokeColor(context, 1.0, 1.0, 1.0, 1.0);
 
// Draw them with a 2.0 stroke width so they are a bit more visible.
CGContextSetLineWidth(context, 2.0);
 
if( [pinFactory actualPinCount] > 1){
 
	Pin *pin1 = (Pin *)[[pinFactory pinArray] objectAtIndex:0];
	CGPoint pt1 = pin1.touchLocation;
	CGContextMoveToPoint(context, pt1.x, pt1.y);
 
	for (int i = 1; i < ([pinFactory actualPinCount]); i++)
	{
		Pin *pin2 = (Pin *)[[pinFactory pinArray] objectAtIndex:i];
		CGPoint pt2 = pin2.touchLocation;
		CGContextAddLineToPoint(context, pt2.x, pt2.y);
	}
 
	CGContextStrokePath(context);
}

8. To draw a polygon, we close the path of lines then fill the polygon.

CGContextClosePath(context);
 
CGContextDrawPath(context, kCGPathFillStroke);

Note: I’ll try to post the sample code when I have time. I’m trying to minimize blogging to 10 mins per post as my work tasks/personal development tasks is piling up…

iPhone Note #12: Adding a UIButton on a UITableViewCell (Borderless)

rupert — Wed, 09 Sep 2009 00:58:08 +0000

1. Im trying to add two UIbuttons to a UITableViewCell, similar to the contacts app. Creating the UIButtons programmatically and adding them to the cell’s subview is trivial. However the interface is a bit different from the contacts app, see image here…

cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"ButtonCell"] autorelease];
 
UIButton *buttonLeft = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[buttonLeft setTitle:@"Left" forState:UIControlStateNormal];
[buttonLeft setFrame: CGRectMake( 10.0f, 3.0f, 145.0f, 40.0f)];
[buttonLeft addTarget:self action:@selector(addToFavorites) forControlEvents:UIControlEventTouchUpInside];
 
UIButton *buttonRight = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[buttonRight setTitle:@"Right" forState:UIControlStateNormal];
[buttonRight setFrame: CGRectMake( 165.0f, 3.0f, 145.0f, 40.0f)];
[buttonRight addTarget:self action:@selector(addToFavorites) forControlEvents:UIControlEventTouchUpInside];
 
[cell addSubview:buttonLeft];
[cell addSubview:buttonRight];

2. So to make the background the same as UITableViewStyleGrouped, we can implement:

cell.backgroundColor = [UIColor groupTableViewBackgroundColor];

But I could still see the border of the UITableViewCell.. see image below…

3. The crux of it was to implement a UIView, set the background as UITableViewStyleGrouped and add that as a cell’s backgroundView.

cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"ButtonCell"] autorelease];
 
UIView *backgroundView = [[UIView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 320.0f, 44.0f)];
backgroundView.backgroundColor = [UIColor groupTableViewBackgroundColor];
 
cell.backgroundView = backgroundView;
 
UIButton *buttonLeft = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[buttonLeft setTitle:@"Left" forState:UIControlStateNormal];
[buttonLeft setFrame: CGRectMake( 10.0f, 3.0f, 145.0f, 40.0f)];
[buttonLeft addTarget:self action:@selector(addToFavorites) forControlEvents:UIControlEventTouchUpInside];
 
UIButton *buttonRight = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[buttonRight setTitle:@"Right" forState:UIControlStateNormal];
[buttonRight setFrame: CGRectMake( 165.0f, 3.0f, 145.0f, 40.0f)];
[buttonRight addTarget:self action:@selector(addToFavorites) forControlEvents:UIControlEventTouchUpInside];
 
[cell addSubview:buttonLeft];
[cell addSubview:buttonRight];
 
[backgroundView release];

Now the interface is a whole lot cleaner and the resulting image is better…

iPhone Note #11: Unit Testing

rupert — Mon, 07 Sep 2009 05:31:43 +0000

Test first, develop later! That’s the greeting when you visit OCUnit, similar to JUnit. Note that for this tutorial, you do not need to install OCUnit as it comes “built-in” in XCode as of v2.1.

1. Create a new iPhone Window-based application project “SampleTest”.

2. Our subject for testing is Converter.m which converts kilometers to meters. Let’s implement an incorrect conversion by specifying 1km = 100 meters (should be 1000 meters) so we can see that the unit test captures it below…

#import "Converter.h"
 
@implementation Converter
 
- (id)init{
	if(self = [super init]){
 
	}
	return self;
}
 
- (int)convertKilometersToMeters:(int)km{
	return km * 100;
}
 
@end

3. Add another target “UnitTests”. Right click on Targets -> Add -> New Target… -> Choose Unit Test Bundle.

4. Name it “UnitTests”. After hitting submit, you will be presented with the project settings for “UnitTests”.

5. Go to the General Tab -> Click on the “+” icon above “Linked Libraries”. Choose “SampleTest” as the application we have direct dependency with.

6. Close the Settings. To check, navigate under “Groups & Files” -> Targets. You should see the SampleTest Application Icon just below “UnitTests”.

7. Right Click on “Sample Test” -> Add -> New File…

8. Name the file “ConverterTest. Don’t forget to also create the header file (default). Specify it also in a different directory under “Location”. Then check the UnitTests as the “Targets”. When you hit “Finish” it will ask you to create the folder “Tests”

Tip: Keep things organize and put it under a “Tests” Group. Right Click on “Sample Test” -> Add -> New Group… Name it “Tests”, then drag the files (ConverterTest.h and ConverterTest.m) into that group.

9. Open up ConverterTest.h and notice that “SenTestingKit.h” is already imported. Now let’s add method testKilometersToMeters as shown below. Test methods usually start out with a test prefix.

In the implementation, let’s import Converter.h and use STAssertTrue. To test the convertKilometersToMeters method, we are asserting that the result should be 1000. If not, then we should know! That is why we are writing a unit test for.. making sure that our implementation doesn’t break.

#import "ConverterTest.h"
#import "Converter.h"
 
@implementation ConverterTest
 
- (void)testKilometersToMeters{
	int km = 1;
	Converter *converter = [[Converter alloc] init];
	int meters = [converter convertKilometersToMeters:km];
	STAssertTrue(meters == 1000, @"converting %d km to meters should equal 1000, instead received %d", km, meters);
}
 
@end

12. Now, before we build our target “UnitTests”, we need to include additional class references from our application. Drag Converter.m to the “Compile Sources” under UnitTests.

13. Now we can build. There are many ways to do this. My preference is to do a clean build when testing. Right Click on Sample Test then choose “Clean SampleTest”. Afterwards choose “Build SampleTest”.

If you have a succesful build for SampleTest, lets do the same for our “UnitTests”.

13. Here’s the crux of it. Notice the error in your “Build Results”?

/Users/rupert/projects/iphone/SampleTest/Tests/ConverterTest.m:18: error: -[ConverterTest testKilometersToMeters] : "meters == 1000" should be true. converting 1 km to meters should equal 1000, instead received 100

Now changing the correct implementation of convertKilometersToMeters will put the error away and you will have a successful build.

- (int)convertKilometersToMeters:(int)km{
	return km * 1000;
}

14. Look up the assert methods from SenTest.h.

#import 
#import "SenTest.h"
 
#define STAssertNil(a1, description, ...)
#define STAssertNotNil(a1, description, ...)
#define STAssertTrue(expression, description, ...)
#define STAssertFalse(expression, description, ...)
#define STAssertEqualObjects(a1, a2, description, ...)
#define STAssertEquals(a1, a2, description, ...)
#define STAssertEqualsWithAccuracy(left, right, accuracy, description, ...)
#define STAssertFalseNoThrow(expression, description, ...)
....

References:

http://developer.apple.com/mac/library/documentation/DeveloperTools/Conceptual/UnitTesting/Articles/CreatingTests.html

http://developer.apple.com/tools/unittest.html

Download: SampleTest.zip

iPhone Note #10: Creating Custom Settings

rupert — Fri, 04 Sep 2009 04:47:49 +0000

1. Create a directory on your desktop, name it “Foo”

2. Download this Sample_plist.txt and place it inside foo. Name it as Root.plist

Foo/
Foo/Root.plist

3. Rename Foo to Settings.bundle

Settings.bundle/
Settings.bundle/Root.plist

4. Drag it to your project.

5. To retrieve a value from the settings.. For example, if we want to retrieve if the “enabled” switch is on or off?

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
BOOL b = [defaults boolForKey:@"enabled_preference"];

Mac Softwares and CheatSheet

rupert — Wed, 26 Aug 2009 11:36:15 +0000

1. iTerm – terminal with tabs.

2. MarsEdit- Blog Software. Im doing a local post on a local wordpress then copying and pasting to a remote wordpress.

3. Mac Shortcuts from http://www.danrodney.com/mac/index.html. Here’s a local post and another one.

4. How to create an ISO?

hdiutil makehybrid -o CS3v1.iso CS3

5. chmOX – CHM Viewer in OSX.

6. Git for OS X from google code.

7. Open a finder from terminal

open .

8. Keychain Access asking on passwordless ssh?

ssh-add
Enter passphrase: ******
ssh-add -l <To list your identities>

iPhone Note #9: Sending or Uploading over HTTP Post

Rupert — Tue, 18 Aug 2009 06:55:11 +0000

In this tutorial, we would use an Objective-C Library: ASIHTTPRequest, which abstracts the complexities of using NSURLConnection

1. Download the latest build.

2. Create a new view based project “HTTPTest”. XCode -> File -> New Project -> View-based Application

3. Add the ff frameworks: CFNetwork, SystemConfiguration, and libz (compression library). For more details, follow these instructions

4. In IB, let’s add two UIButton’s, a UITextView *textView and a UIProgressView *progressView. The two buttons is for HTTP URL and HTTP FORM requests. The textView will display the response of the HTTP request. While the progressView is for displaying the uploading progress. It should look something similar to the image below…

5. Here is the interface:

#import
 
@interface HTTPTestViewController : UIViewController {
	IBOutlet UIButton *buttonSubmitURL;
	IBOutlet UIButton *buttonSubmitForm;
	IBOutlet UITextView *textView;
	IBOutlet UIProgressView *progressView;
 
	NSOperationQueue *queue;
}
 
@property (nonatomic, retain) IBOutlet UIButton *buttonSubmitURL;
@property (nonatomic, retain) IBOutlet UIButton *buttonSubmitForm;
@property (nonatomic, retain) IBOutlet UIProgressView *progressView;
 
@property (nonatomic, retain) IBOutlet UITextView *textView;
 
- (IBAction)submitURLPressed;
 
- (IBAction)submitFormPressed;
 
@end

6. In IB, hook up the IBAction method’s from the “Touch Up Inside” events for each button.

URL Button -> Touch Up Inside -> submitURLPressed
Form Button -> Touch Up Inside -> submitFormPressed

7. Let’s do the URL first. From the code snippet below, notice that it is a UI blocking call as the call is synchronous. From the “How to use it” section of ASI’s website:

The simplest way to use ASIHTTPRequest. Sending the start message will execute the request in the same thread, and return control when it has completed (successfully or otherwise).

- (IBAction)submitURLPressed{
	textView.text = @"";
 
	NSURL *url = [NSURL URLWithString:@"http://192.168.1.188/iphone/test.cfm"];
 
	ASIHTTPRequest *request = [[[ASIHTTPRequest alloc] initWithURL:url] autorelease];
 
	[request start];
 
	NSError *error = [request error];
 
	if (!error) {
		NSString *response = [request responseString];
		NSLog(@"Result string: %@", response);
 
		textView.text = response;
	}
}

8. Now let’s do an asynchronous request so the UI can respond using the progressView. Implement the code snippet below for submitFormPressed. Notice, that I am using an image (http_test.gif) which is bundled up in the application. After creating the *request, I made HTTPTestViewController as the delegate. Therefore we need to implement methods requestDone and requestWentWrong in step [9].

To add a form value, simple do [request setPostValue:@"rupert" forKey:@"name"];

To add a file, simple pass the NSString path to setFile, i.e:
[request setFile:imagePath1 forKey:@"file"];

- (IBAction)submitFormPressed{
	queue = [[NSOperationQueue alloc] init];
	[queue setMaxConcurrentOperationCount:1];
 
	NSString *imagePath1 = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"http_test.gif"];
 
	textView.text = @"";
 
	[progressView setProgress:0];
 
	NSURL *url = [NSURL URLWithString:@"http://192.168.1.193/dbydsms/upload.aspx"];
 
	ASIFormDataRequest *request = [[[ASIFormDataRequest alloc] initWithURL:url] autorelease];
 
	[request setDelegate:self];
	[request setDidFinishSelector:@selector(requestDone:)];
	[request setDidFailSelector:@selector(requestWentWrong:)];
 
	[request setPostValue:@"rupert" forKey:@"name"];
 
	[request setFile:imagePath1 forKey:@"file"];
 
	[request setUploadProgressDelegate:progressView];
 
	[queue addOperation:request];
}

9. Conforming to the delegate’s methods…

- (void)requestDone:(ASIHTTPRequest *)request
{
	NSLog(@"Value: %f", [progressView progress]);
 
	NSError *error = [request error];
 
	if (!error) {
		NSString *response = [request responseString];
		NSLog(@"Result string: %@", response);
 
		textView.text = response;
	}
}
 
- (void)requestWentWrong:(ASIHTTPRequest *)request
{
	NSError *error = [request error];
	NSLog(@"error: %@", error);
}

10. For the upload.aspx,

protected void Page_Load(object sender, EventArgs e)
    {
        HttpFileCollection uploadFiles = Request.Files;
 
        // Loop over the uploaded files and save to disk.
        int i;
        for (i = 0; i &lt; uploadFiles.Count; i++)
        {
            HttpPostedFile postedFile = uploadFiles[i];
 
            // Access the uploaded file's content in-memory:
            System.IO.Stream inStream = postedFile.InputStream;
            byte[] fileData = new byte[postedFile.ContentLength];
            inStream.Read(fileData, 0, postedFile.ContentLength);
 
            // Save the posted file in our "data" virtual directory.
            postedFile.SaveAs("E:\\RupertWork\\wwwroot\\project\\uploads\\" + postedFile.FileName);
 
        }
 
    }

iPhone Quick Tip #2: Creating Objective-C Class Diagrams Instantly

Rupert — Mon, 17 Aug 2009 23:58:02 +0000

Omnigraffle provides a quick and dirty class diagram when you open your XCode projects. Very cool and saves you a lot of time than using VISIO.

1. Simple go to Omnigraffle -> File -> Open. Navigate to your_project.xcodeproj

2. A popup like below will even let you configure if you want to map out the protocols and categories. Normally, the ivars and methods are checked by default.

iPhone Note #8: Exporting Oracle to SQLite3

Rupert — Sun, 16 Aug 2009 12:31:09 +0000

Since I’ve been working most of my time with iPhone Dev for the last couple of months, I thought it will be worthwile to post how to import files to SQLite3. In a nutshell, use MesaSQLite’s IMPORT function. It will save you a lot of time. Now it is up to you how to export into a CSV or TAB delimited file. For Oracle, I used SQLDeveloper. For other databases, such as MySQL or Postgres, I’ve used Navicat.

1. Using SQLDeveloper -> Right Click on the Table from the left pane -> Export

2. Choose TEXT since we are going to use that when importing using MesaSQLite. Note, SQLDeveloper does not export CLOB columns. You need to change your column from CLOB to VARCHAR. A workaround is to add a column and then update that column aferwards.

ALTER TABLE poi ADD en_desc VARCHAR(2000);
UPDATE poi SET en_desc = en_short_desc;

3. In MesaSQLite, FILE -> IMPORT -> CSV/TAB

4. Choose the table which you want to import.

5. Choose your exported TAB delimited file from SQLDeveloper.

6. Afterwards, map the corresponding fields to your database. Note, that I added an extra column “dummy” in the file because it seems I can only match n-1 columns, thus the extra column.

iPhone Note #7: TableView as Single Selections

Rupert — Fri, 14 Aug 2009 05:33:44 +0000

Today, I came up with a generic UITableViewController that allows single selections.

Part 1: Creating the view controller..

1. File -> New File -> UIViewController subclass. Check the checkbox UITableViewController subclass.

CheckListTableViewController will be referred to as the controller from here on..

2. The controller will accept:

a. NSArray *array – which holds the items.
b. NSString *title – title of the selection.

3. I also added a protocol declaration for the controller when the user presses “Done” on the right portion of the Navbar.

CheckListTableViewController.h

#import
 
@protocol CheckListTableViewControllerDelegate;
 
@interface CheckListTableViewController : UITableViewController {
	//NSString *title;
	NSString *chosenString;
	NSArray *array;
	id delegate;
}
 
//@property(nonatomic, copy) NSString *title;
@property(nonatomic, retain) NSArray *array;
@property(assign) id delegate;
 
- (id)initWithStyle:(UITableViewStyle)style withTitle:(NSString *)t withArray:(NSArray *)a;
 
- (void)doneButtonPressed;
 
- (void)initButton;
 
@end
 
@protocol CheckListTableViewControllerDelegate
 
@optional
 
-(void)checkListTableViewController:(CheckListTableViewController *)controller didChooseString:(NSString *)chosenString;
 
@end

4. In the cellForRowAtIndexPath, we display the checkmark if the cell’s current String is the same as the chosen String. The chosenString is an ivar which gets assigned during didSelectRowAtIndexPath. Notice that the assignment is performed AFTER the condition of comparing the strings.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
 
    static NSString *CellIdentifier = @"Cell";
 
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    }
 
    // Set up the cell...
	NSString *currentString = (NSString *)[array objectAtIndex:indexPath.row];
	cell.textLabel.text = currentString;
	cell.textLabel.adjustsFontSizeToFitWidth = YES;
 
	if([currentString localizedCaseInsensitiveCompare:chosenString] == NSOrderedSame ){
		[cell setAccessoryType:UITableViewCellAccessoryCheckmark];
	}
	else{
		[cell setAccessoryType:UITableViewCellAccessoryNone];
	}
 
 
    return cell;
}
 
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    // Navigation logic may go here. Create and push another view controller.
	// AnotherViewController *anotherViewController = [[AnotherViewController alloc] initWithNibName:@"AnotherView" bundle:nil];
	// [self.navigationController pushViewController:anotherViewController];
	// [anotherViewController release];
	NSLog(@"User seleced row %d", indexPath.row);
 
	NSString *currentString = (NSString *)[array objectAtIndex:indexPath.row];
 
	if([currentString localizedCaseInsensitiveCompare:chosenString] == NSOrderedSame ){
		[[tableView cellForRowAtIndexPath:indexPath] setAccessoryType:UITableViewCellAccessoryCheckmark];
	}
	else{
		[[tableView cellForRowAtIndexPath:indexPath] setAccessoryType:UITableViewCellAccessoryNone];
	}
 
	chosenString = currentString;
 
	[tableView reloadData];
}

Part 2: Calling the controller from a client.

1. Make the client conform to the CheckListTableViewControllerDelegate.

#import
....
#import "DatePickerViewController.h"
#import "CheckListTableViewController.h"
 
@interface JobProfileViewController : UIViewController {

2. You can even reuse the controller for different lists, say we have two lists:”Purpose” and “Location”

- (IBAction)showPurposePicker{
	NSLog(@"purpose button clicked");
 
	NSArray *array = [[NSArray alloc] initWithObjects:@"Design", @"Testing", nil];
	NSString *title = @"Purpose";
 
	[self displayModalPickerForTitle:title withArray:array];
}
 
- (IBAction)showLocationOfWorkplace{
	NSArray *array = [[NSArray alloc] initWithObjects:@"Both", @"Private", @"Public", nil];
	NSString *title = @"Location";
 
	[self displayModalPickerForTitle:title withArray:array];
}

3. The controller is added to a Navigation Controller which is presented modally. Courtesy of the help of Erica Sadun from IRC.

- (void)displayModalPickerForTitle:(NSString *)title withArray:(NSArray *)array{
 
	CheckListTableViewController *listController = [[CheckListTableViewController alloc] initWithStyle:UITableViewStylePlain withTitle:title withArray:array];
	listController.delegate = self;
 
	UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:listController];
	[self presentModalViewController:nav animated:YES];
 
	[listController release];
	[nav release];
}

4. When the user is finished with the control, the client performs its necessary processes and dismisses the modal view.

-(void)checkListTableViewController:(CheckListTableViewController *)controller didChooseString:(NSString *)chosenString{
	NSLog(@"Chosen String: %@", chosenString);
	NSLog(@"Title: %@", controller.title);
 
	if( controller.title == @"Purpose"){
		job.purpose = chosenString;
		[purpose setTitle:job.purpose forState:UIControlStateNormal];
	}
	else if( controller.title == @"Principal Excavation Activity"){
		job.principalExcavationActivity = chosenString;
		[principalExcavationActivity setTitle:job.principalExcavationActivity forState:UIControlStateNormal];
	}
	else if( controller.title == @"Location Of Workplace"){
		job.locationOfWorkplace = chosenString;
		[locationOfWorkplace setTitle:job.locationOfWorkplace forState:UIControlStateNormal];
	}
 
	[self dismissModalViewControllerAnimated:YES];
}

iPhone Note #6: Presenting a DatePicker as a ViewController Modally

Rupert — Thu, 13 Aug 2009 02:38:23 +0000

Part 1: Creating your own control inside a view controller..

1. File -> New. Choose UIViewController subclass. Tick the checkbox “With XIB for user interface”. Save it as “DatePickerViewController”.

2. Open the DatePickerViewController.xib from IB.

3. In IB, drag a UIDatePicker and a UIButton as shown below.

4. In DatePickerViewController.h,

#import
 
@protocol DatePickerViewControllerDelegate;
 
@interface DatePickerViewController : UIViewController {
	IBOutlet UIDatePicker *datePicker;
	id delegate;
}
 
@property (retain) IBOutlet UIDatePicker *datePicker;
@property (assign) id delegate;
 
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil;
 
- (IBAction)doneButtonPressed:(id)sender;
@end
 
@protocol DatePickerViewControllerDelegate
 
@optional
-(void)datePickerViewController:(DatePickerViewController *)controller didChooseDate:(NSString *)chosenDate;
 
@end

5. Now, lets hook up the “doneButtonPressed” in IB. In IB -> Tools -> Connections Inspector. Drag the touch “Touch Up Inside” event to the File’s Owner which is DatePickerViewController. Choose the method “doneButtonPressed:” when it shows up.

6. Next, implement the doneButtonPressed

#import "DatePickerViewController.h"
 
@implementation DatePickerViewController
 
@synthesize datePicker, delegate;
 
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        // Custom initialization
		self.title = @"Date Picker";
    }
    return self;
}
 
 
//-(void)datePickerViewController:(DatePickerViewController *)controller didChooseDate:(NSString *)chosenDate;
 
- (IBAction)doneButtonPressed:(id)sender
{
    if ([self.delegate respondsToSelector:@selector(datePickerViewController:didChooseDate:)]) {
		NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init]  autorelease];
		[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
 
		NSString *dateString = [dateFormatter stringFromDate:[datePicker date]];
 
        [self.delegate datePickerViewController:self didChooseDate:dateString];
    }
}
 
- (void)dealloc {
	[datePicker release];
    [super dealloc];
}
 
@end

Part 2: Displaying the view controller modally

7. From this point on, I will refer to JobProfileViewController as the client. The client will create and present the DatePickerViewController modally (which is now referred to as picker). Once the user is finished using the picker and hits the “Done” button, the client will dismiss the picker and process the returned results.

8. Make the client conform to the DatePickerViewControllerDelegate.

#import "DatePickerViewController.h"
 
@interface JobProfileViewController : UIViewController {

9. Trigger an event to create and present the picker modally. In my case, its a button which is hooked up to showDatePicker method. Now, make the client as the delegate for the picker. Present the content modally then release the object.

JobProfileViewController.h:

- (IBAction)showDatePicker{
	DatePickerViewController *datePickerViewController = [[DatePickerViewController alloc] initWithNibName:@"DatePickerViewController" bundle:nil];
	datePickerViewController.delegate = self;
 
	[self presentModalViewController:datePickerViewController animated:YES];
 
	[datePickerViewController release];
}

10. Since the client is now the delegate for the picker, we can implement “didChooseDate” method inside the client. It is good practice that whoever (in our case the client) presents the content modally should also dismiss the content. Process what needs to be done, then let’s dismiss the modal content. Note: There is only one modal content for every view controller.

JobProfileViewController.h:

-(void)datePickerViewController:(DatePickerViewController *)controller didChooseDate:(NSString *)chosenDate{
	NSLog(@"Chosen Date as String: %@", chosenDate );
 
	job.startDate = chosenDate;
	[startDate setTitle: chosenDate forState: UIControlStateNormal];
 
	[self dismissModalViewControllerAnimated:YES];
}

UPDATE OCT 2, 2009: Download DatePickerModalExample.zip