【iOS】iPod Library Accessの使い方（２）簡易音楽プレイヤーを作る

【iOS】iPod Library Accessの使い方（１）曲情報を取得するの続き

再生・停止・曲送り、曲戻し、アーティスト／タイトル／ジャケット写真の表示、ができる簡易な音楽プレイヤーを作りました。
NSNotificationCenterって便利ね。

コード

JPlayerViewController.h

//
//  JPlayerViewController.h
//  JPlayer
//
//  Created by jonki on 12/12/26.
//  Copyright (c) 2012年 jonki. All rights reserved.
//

#import <UIKit/UIKit.h>
#import <MediaPlayer/MediaPlayer.h>

@interface JPlayerViewController : UIViewController

@property BOOL isPlaying;
@property MPMusicPlayerController *player;
@property NSNotificationCenter *ncenter;


// 各ウィジェットとそれに紐付くIBAction
@property (strong, nonatomic) IBOutlet UIButton *nextButton;
- (IBAction)pushedNextButton:(id)sender;
@property (strong, nonatomic) IBOutlet UIButton *playOrStopButton;
- (IBAction)pushedPlayOrStopBUtton:(id)sender;
@property (strong, nonatomic) IBOutlet UIButton *prevButton;
- (IBAction)pushedPrevButton:(id)sender;
@property (strong, nonatomic) IBOutlet UILabel *songInfoLabel;
@property (strong, nonatomic) IBOutlet UILabel *artistInfoLabel;
@property (strong, nonatomic) IBOutlet UIImageView *artworkImage;


@end

JPlayerViewController.m

//
//  JPlayerViewController.m
//  JPlayer
//
//  Created by jonki on 12/12/26.
//  Copyright (c) 2012年 jonki. All rights reserved.
//

#import "JPlayerViewController.h"

@interface JPlayerViewController ()

@end

@implementation JPlayerViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
    
    // とりあえず起動時に全曲シャッフルして再生キューにぶっこむ
    _player = [MPMusicPlayerController applicationMusicPlayer];
    [_player setQueueWithQuery:[MPMediaQuery songsQuery]];
    [_player setShuffleMode:MPMusicShuffleModeSongs];
    [_player play];
    _isPlaying = YES;
    [_playOrStopButton setTitle:@"Ⅱ" forState:UIControlStateNormal];
    
    // Notificationの設定
    _ncenter = [NSNotificationCenter defaultCenter];
    [_ncenter addObserver:self
              selector: @selector(handle_PlaybackStateChanged)
              name:MPMusicPlayerControllerPlaybackStateDidChangeNotification
              object:_player];
    [_ncenter addObserver:self
              selector:@selector(handle_NowPlayingItemChanged)
              name:MPMusicPlayerControllerNowPlayingItemDidChangeNotification
              object:_player];
    [_ncenter addObserver:self
                 selector:@selector(handle_VolumeChanged)
                     name:MPMusicPlayerControllerVolumeDidChangeNotification
                   object:_player];
    [_player beginGeneratingPlaybackNotifications];
    
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)viewDidUnload {
    // Notificationの解除
    [_ncenter removeObserver:self];
    [_player endGeneratingPlaybackNotifications];
    
    [self setNextButton:nil];
    [self setPrevButton:nil];
    [self setPlayOrStopButton:nil];
    [self setSongInfoLabel:nil];
    [self setArtistInfoLabel:nil];
    [self setArtworkImage:nil];
    [super viewDidUnload];
}


#pragma mark 音楽ののNotificationハンドラ
- (void)handle_PlaybackStateChanged {
    NSLog(@"PlaybackSattechanged");
}

- (void)handle_NowPlayingItemChanged {
    NSLog(@"NowPlayingItemChanged");
    
    MPMediaItem *nowPlayingItem = [_player nowPlayingItem];
    NSString *artist = [nowPlayingItem valueForProperty:MPMediaItemPropertyArtist];
    NSString *title  = [nowPlayingItem valueForProperty:MPMediaItemPropertyTitle];

    _songInfoLabel.text = title;
    _artistInfoLabel.text = artist;

    MPMediaItemArtwork *artwork = [nowPlayingItem valueForProperty:MPMediaItemPropertyArtwork];
    UIImage *image = [artwork imageWithSize:CGSizeMake(140.0f, 140.0f)];
    [_artworkImage setImage:image];
}

- (void)handle_VolumeChanged {
    NSLog(@"VolumeChanged");
}

#pragma mark 音楽の操作

- (IBAction)pushedNextButton:(id)sender {
    [_player skipToNextItem];
}

- (IBAction)pushedPlayOrStopBUtton:(id)sender {
    if( _isPlaying )
    {
        [_player pause];
        [_playOrStopButton setTitle:@"再生" forState:UIControlStateNormal]; //再生マークは機種依存でhatenaに投稿できないので漢字で
        _isPlaying = NO;
    }
    else
    {
        [_player play];
        [_playOrStopButton setTitle:@"Ⅱ" forState:UIControlStateNormal];
        _isPlaying = YES;
    }
}

- (IBAction)pushedPrevButton:(id)sender {
    [_player skipToPreviousItem];
}

#pragma mark デバッグプリント用に残してある
- (void)showNowPlayingSongInfo {
    NSLog(@"現在再生中の曲情報を表示する");
    MPMediaItem *nowPlayingItem = [_player nowPlayingItem];
    NSLog(@"Genre       = %@", [nowPlayingItem valueForProperty:MPMediaItemPropertyGenre]);
    NSLog(@"Album Title = %@", [nowPlayingItem valueForProperty:MPMediaItemPropertyAlbumTitle]);
    NSLog(@"Artist      = %@", [nowPlayingItem valueForProperty:MPMediaItemPropertyArtist]);
    NSLog(@"Title       = %@", [nowPlayingItem valueForProperty:MPMediaItemPropertyTitle]);
}

- (void)showSongInfoWithSongQuery {
    NSLog(@"曲名でソートして、全曲リストを表示する");
    MPMediaQuery *query = [MPMediaQuery songsQuery];
    int counter = 0;
    for( MPMediaItem *item in [query items])
    {
        NSLog(@"%@", [item valueForProperty:MPMediaItemPropertyTitle]);
        ++counter;
        if(counter > 4) break; // 全部出すと多いのでこの辺でbreak
    }
}

- (void)showSongInfoWithArtistQuery {
    NSLog(@"アーティスト名でソートして、全曲リストを表示する");
    MPMediaQuery *query = [MPMediaQuery artistsQuery];
    int counter = 0;
    for( MPMediaItem *item in [query items])
    {
        NSLog(@"%@", [item valueForProperty:MPMediaItemPropertyArtist]);
        ++counter;
        if(counter > 4) break; // 全部出すと多いのでこの辺でbreak
    }
}

- (void)showPlaylistInfo {
    NSLog(@"プレイリストを表示する");
    MPMediaQuery *query = [MPMediaQuery playlistsQuery];
    for( MPMediaPlaylist *plist in [query collections] )
    {
        NSLog(@"%@", [plist valueForProperty:MPMediaPlaylistPropertyName]);
    }
}

@end