Using iPod Library

YOU APPLICATION -------------->     MUSIC PLAYER(music play back)

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MEDIA PICKER MEDIA QUERY

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iPod Library

(data base access)

Music Player :

There are 2 flavors of music players available:

1. Application music player : Plays music locally within your application.It does not effect built in iPod app
2. iPod music player : In effect,employes the built-in ipod app on your behalf.When auger quits an app that is using this player,the music continues to play.

Creating iPodMusicPlayer:

MPMusicPlayerController* iPodMusicPlyer = [MPMusicPlyerController iPodMusicPlayer];

Data base access:

2 ways to retrieve items(data base access)

1. The media item picker : It is an easy to use, pre-packaged view controller that behaves like the built-in iPod application's music selection interface.
2. The media Query : To provide the specialized access control that you want, the media query interface.

Using the Media Item Picker:

MPMediaPickerController : It is a specialized view controller that you employ to provide a graphical interface for selecting media items.To respond to user selections and to dismiss a media item picker, use the MPMediaPickerControllerDelegate protocol.

MPMediaPickerControllerDelegate protocol : The delegate for a media item picker can respond to a user making media item selections.The delegate is also responsible for dismissing the media item picker from the parent view controller.

Steps for using media item picker:

1. Designate a controller object as a delegate of the picker.
2. Invoke the picker from the controller.
3. When the use indicates that they are finished, the delegate receives the chosen collection of media items and dismiss the picker.

STEP1 : Add the protocol name in the interface declaration.

@interface myController : UIViewController { // interface declaration

}

STEP2 : Invoke the picker from controller

1. Create a media item picker .MPMediaPickerController* picker = [[MPMediaPickerController alloc] initWithMediaTypes:MPMediaTypeAnyAudio];
2. Establishes your controller objects the delegate.[picker setDelegate:self];
3. Specifies the user can pick multiple items. [picker setAllowsPickingMultipleItems: YES];
4. Optional setting A prompt, for user,that appears above the navigation bar.picker.prompt = NSLocalizedString(@"Add songs to play",@"prompt in media item picker");
5. Display the picker.[self presentModalViewController:picker animated: YES];[picker release];

STEP3 : Implement 2 delegate methods("mediaPicker:didPickMediaItems:"  and "mediaPickerDidCancel") to suspend picker controller.

Useful methods:

mediaPicker:didPickMediaItems:

Called when a user has selected a set of media items.

- (void)mediaPicker: (MPMediaPickerController *)mediaPicker didPickMediaItems:(MPMediaItemCollection *)mediaItemCollection

mediaPickerDidCancel:

Called when a user dismisses a media item picker by tapping Cancel.

- (void)mediaPickerDidCancel:(MPMediaPickerController *)mediaPicker

[self dismissModalViewControllerAnimated:YES]

Updating playback :

Code here is self explanatory.

- (void) updatePlayerQueueWithMediaCollection: (MPMediaItemCollection *) mediaItemCollection {

// Configure the music player, but only if the user chose at least one song to play

if (mediaItemCollection) {

// If there's no playback queue yet...

if (userMediaItemCollection == nil) {

// apply the new media item collection as a playback queue for the music player

[self setUserMediaItemCollection: mediaItemCollection];

[musicPlayer setQueueWithItemCollection: userMediaItemCollection];

[musicPlayer play];

// Obtain the music player's state so it can then be

// restored after updating the playback queue.

} else {

// Take note of whether or not the music player is playing. If it is

// it needs to be started again at the end of this method.

BOOL wasPlaying = NO;

if (musicPlayer.playbackState == MPMusicPlaybackStatePlaying) {

wasPlaying = YES;

}

// Save the now-playing item and its current playback time.

MPMediaItem *nowPlayingItem = musicPlayer.nowPlayingItem;

NSTimeInterval currentPlaybackTime = musicPlayer.currentPlaybackTime;

// Combine the previously-existing media item collection with the new one

NSMutableArray *combinedMediaItems = [[userMediaItemCollection items] mutableCopy];

NSArray *newMediaItems = [mediaItemCollection items];

[combinedMediaItems addObjectsFromArray: newMediaItems];

[self setUserMediaItemCollection: [MPMediaItemCollection collectionWithItems: (NSArray *) combinedMediaItems]];

[combinedMediaItems release];

// Apply the new media item collection as a playback queue for the music player.

[musicPlayer setQueueWithItemCollection: userMediaItemCollection];

// Restore the now-playing item and its current playback time.

musicPlayer.nowPlayingItem = nowPlayingItem;

musicPlayer.currentPlaybackTime = currentPlaybackTime;

// If the music player was playing, get it playing again.

if (wasPlaying) {

[musicPlayer play];

}

}

}

}