如何显示从avplayer播放的ipodLibrary中选定的歌曲在uitableview中播放

Question

我正在使用AVPlayer播放歌曲。我也能够在后台播放它。有一个UIButton调用showPlaylist。当我点击它时，我需要显示我从ipodLibrary在UITableView中选择的歌曲列表，并且我应该能够显示艺术作品，歌曲中剩余的分钟数以及艺术家的名字（如果歌曲中可用）。

我有播放和暂停按钮：当我点击暂停按钮，歌曲暂停，但当我再次点击播放按钮时，它会进入ipodLibrary。当我点击播放按钮时如何恢复播放？

当UITableView中有多首歌曲时，我希望它在第一首曲目完成后立即继续下一首歌曲。我想知道如何做到这一点。

-(IBAction)playButtonPressed:(UIButton *)sender { 
    // Create picker view 
    MPMediaPickerController* picker = [[MPMediaPickerController alloc] init]; 
    picker.delegate = self; 
    if (userMediaItemCollection) { 
    MusicTableViewController *controller = [[MusicTableViewController alloc] 
    initWithNibName: @"MusicTableView" bundle: nil]; 
    controller.delegate = self; 
    controller.modalTransitionStyle = UIModalTransitionStyleCoverVertical; 
    [self presentModalViewController: controller animated: YES]; 
    } else { 
    MPMediaPickerController *picker = [[MPMediaPickerController alloc] 
     initWithMediaTypes: MPMediaTypeMusic]; 
    picker.delegate = self; 
    picker.allowsPickingMultipleItems = YES; 
    picker.prompt = NSLocalizedString 
     (@"Add songs to play", "Prompt in media item picker"); 
    [[UIApplication sharedApplication] setStatusBarStyle: 
     UIStatusBarStyleDefault animated: YES]; 
    [self presentModalViewController: picker animated: YES]; 
    } 
} 

-(IBAction)pauseButtonPressed:(UIButton *)sender { 
    [myPlayer pause]; 
} 

-(void) mediaPickerDidCancel:(MPMediaPickerController *)mediaPicker { 
    [self dismissViewControllerAnimated:YES completion:nil]; 
} 

-(void) mediaPicker:(MPMediaPickerController *)mediaPicker didPickMediaItems: 
    (MPMediaItemCollection *)mediaItemCollection { 
    [self dismissViewControllerAnimated:YES completion:nil]; 
    NSURL* assetUrl = [mediaItemCollection.representativeItem 
    valueForProperty:MPMediaItemPropertyAssetURL]; 
    AVURLAsset* asset = [AVURLAsset URLAssetWithURL:assetUrl options:nil]; 
    AVPlayerItem* playerItem = [AVPlayerItem playerItemWithAsset:asset]; 
    myPlayer = [AVPlayer playerWithPlayerItem:playerItem]; 
    [myPlayer play]; 
} 

- (void)viewDidAppear:(BOOL)animated { 
    [super viewDidAppear:animated]; 
    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents]; 
    [self becomeFirstResponder]; 
} 

- (BOOL)canBecomeFirstResponder { 
    return YES; 
} 

- (void)viewWillDisappear:(BOOL)animated { 
    [super viewWillDisappear:animated]; 
    [[UIApplication sharedApplication] endReceivingRemoteControlEvents]; 
    [self resignFirstResponder]; 
} 

-(void)remoteControlReceivedWithEvent:(UIEvent *)event { 
    switch (event.subtype) { 
    case UIEventSubtypeRemoteControlTogglePlayPause: 
     if (myPlayer.rate == 0.0) { 
     [myPlayer play]; 
     } else { 
     [myPlayer pause]; 
     } 
     break; 
    case UIEventSubtypeRemoteControlPlay: 
     [myPlayer play]; 
     break; 
    case UIEventSubtypeRemoteControlPause: 
     [myPlayer pause]; 
     break; 
    default: 
     break; 
    } 
} 

Answer 1

我会看看苹果的示例代码"Add Music"，它清楚地演示了如何做你所描述的一切。

本示例应用程序通过填充UITableView的示例应用程序运行，其中包含从iPod库中选定歌曲的可变副本内容保存到MPMediaItemCollection。它还显示了如何使用MPMediaItems和MPMediaItemCollections您可以显示轨道特定属性作为单元格标题标签等

1. 用于填充表视图，您可以将其设置是这样的：

   MPMediaItem *mediaItem = (MPMediaItem *)[collectionMutableCopy objectAtIndex:row];

   MPMediaItemArtwork *artwork = [mediaItem valueForProperty:MPMediaItemPropertyArtwork];

   if (mediaItem) { 
       cell.textLabel.text = [mediaItem valueForProperty:MPMediaItemPropertyTitle]; 
       cell.detailTextLabel.text = [mediaItem valueForProperty:MPMediaItemPropertyArtist]; 
       if (artwork != nil) { 
        cell.imageView.image = [artwork imageWithSize:CGSizeMake (40, 40)]; 
       }else{ 
        cell.imageView.image = [UIImage imageNamed:@"no_artwork.png"]; 
       } 
   } 
   

2. 重命名按钮链接到播放按钮“选择音乐“并设置一个名为”播放“的新按钮，其动作设置为：

   - (IBAction)playMusic { [myPlayer play]; }

编辑：从MPMediaItemCollection内容创建阵列：

NSMutableArray *collectionMutableCopy = [[NSMutableArray alloc] initWithArray:myMediaItemCollection.items]; 

编辑2：取消注释项目中的下列行：

在- (void) registerForMediaPlayerNotifications

/* 
// This sample doesn't use libray change notifications; this code is here to show how 
//  it's done if you need it. 
[[NSNotificationCenter defaultCenter] removeObserver: self 
name: MPMediaLibraryDidChangeNotification 
object: musicPlayer]; 

[[MPMediaLibrary defaultMediaLibrary] endGeneratingLibraryChangeNotifications]; 

*/ 

在- (void)dealloc

/* 
// This sample doesn't use libray change notifications; this code is here to show how 
//  it's done if you need it. 
[notificationCenter addObserver: self 
selector: @selector (handle_iPodLibraryChanged:) 
name: MPMediaLibraryDidChangeNotification 
object: musicPlayer]; 

[[MPMediaLibrary defaultMediaLibrary] beginGeneratingLibraryChangeNotifications]; 
*/ 

替换此行：

[[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryAmbient error: nil]; 

有了这个

[[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryPlayback error: nil]; 

UInt32 doSetProperty = 0; 
AudioSessionSetProperty (
kAudioSessionProperty_OverrideCategoryMixWithOthers, 
sizeof (doSetProperty), 
&doSetProperty 
); 

然后添加以下到您的项目Info.plist文件

Answer 2

你的问题是，你的播放按钮正在做的不只是告诉音乐播放器玩。你需要一个只需拨打[myPlayer play];除了播放按钮之外，将所有设置都放在其他地方。

让你的播放按钮也选择歌曲并不是很好的编码习惯（最好保留一个按钮 - >一个功能）。所以，有一个按钮，不会在你的播放按钮，现在是什么，然后让你的播放按钮，只需要调用[myPlayer play]

至于你的其他问题，你应该看看这个：Play multiple audio files using AVAudioPlayer

只要你知道，你”实际上不应该在同一篇帖子中提出多个问题。这使得它更难以给出一个简洁有用的答案，并可以使网站更难找到的东西。

我不确定你是否问如何显示歌曲信息，但我想它是在你的标题。对于这一个，iPhone sdk - accessing current song information through an app。