2

如何使用 AVPlayer 立即开始下一首歌曲？我有从 MPMediaItemCollection 中的 iPod 库中选择的歌曲集合，显示在我的 UITableView [myPlaylistTable]中。我知道我必须使用 NSNotification 来检查歌曲是否已经完成，但我不知道如何在当前歌曲播放完毕后立即播放第二首或下一首歌曲。我在下面发布了我的代码

如果有人可以帮助我解决问题，将不胜感激。谢谢

   in viewDidLoad i have initialized 

- (void)viewDidLoad
{
    [super viewDidLoad];

    //[[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
    [self.myPlaylistTable deselectRowAtIndexPath:[self.myPlaylistTable indexPathForSelectedRow] animated:NO];

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

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

    [self becomeFirstResponder];

    myPlaylistTable.hidden=YES;

    playlistSongsArray =[[NSMutableArray alloc]init];

[[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(nextSongPlaying:)
                                                     name:AVPlayerItemDidPlayToEndTimeNotification
                                                   object:[myPlayer currentItem]];

}      



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

    // Dismiss selection view
    [self dismissViewControllerAnimated:YES completion:nil];


    // Get AVAsset
    NSURL* assetUrl = [mediaItemCollection.representativeItem valueForProperty:MPMediaItemPropertyAssetURL];
    AVURLAsset* asset = [AVURLAsset URLAssetWithURL:assetUrl options:nil];


    AVPlayerItem* playerItem = [AVPlayerItem playerItemWithAsset:asset];


    myPlayer = [AVPlayer playerWithPlayerItem:playerItem];

    [playlistSongsArray addObjectsFromArray:mediaItemCollection.items];

    NSLog(@" Playlist songs  %@",playlistSongsArray);

    [self.myPlaylistTable reloadData];

    [myPlayer play];

}

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];

    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];
    [self becomeFirstResponder];
}

- (BOOL)canBecomeFirstResponder 
{
    return YES;
}

- (UITableViewCell *) tableView: (UITableView *)tableView cellForRowAtIndexPath: (NSIndexPath *) indexPath {

    NSInteger row = [indexPath row];
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier: kCellIdentifier];


    if (cell == nil) {

        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:kCellIdentifier];


            UILabel *playbackDurationLabel =[[UILabel alloc]initWithFrame:CGRectMake(205, 88, 103, 18)];
            playbackDurationLabel.tag = 100;
            playbackDurationLabel.backgroundColor = [UIColor clearColor];
            playbackDurationLabel.textColor = [UIColor orangeColor];

            playbackDurationLabel.font = [UIFont fontWithName:@"Helvetica" size:14];

            [cell.contentView addSubview:playbackDurationLabel];

    }   

    if (tableView == myPlaylistTable)
    {
        MPMediaItem *mediaItem = (MPMediaItem *)[playlistSongsArray objectAtIndex:row]; 
        MPMediaItemArtwork *artwork = [mediaItem valueForProperty:MPMediaItemPropertyArtwork];


        if (mediaItem) 
        {
            cell.textLabel.text = [mediaItem valueForProperty:MPMediaItemPropertyTitle];
            cell.textLabel.textColor = [UIColor redColor];
            cell.textLabel.font = [UIFont fontWithName:@"Helvetica" size:15];
            cell.textLabel.numberOfLines=0;

            cell.detailTextLabel.text = [mediaItem valueForProperty:MPMediaItemPropertyArtist];
            cell.detailTextLabel.textColor = [UIColor blueColor];
            cell.detailTextLabel.font = [UIFont fontWithName:@"Helvetica" size:14];
            cell.detailTextLabel.numberOfLines=0;

            UILabel *songDurationLabel = (UILabel *) [cell.contentView viewWithTag:100];
            songDurationLabel.text=[self secondsFormatted:[[mediaItem valueForProperty:MPMediaItemPropertyPlaybackDuration] intValue]];

            NSLog(@"song duration - %@",[[mediaItem valueForProperty:MPMediaItemPropertyPlaybackDuration] stringValue]);

            if (artwork != nil) 
            {
                cell.imageView.image = [artwork imageWithSize:CGSizeMake(60, 60)];
            }
            else
            {
                cell.imageView.image = [UIImage imageNamed:@"noArtworkImage.png"];
            }
        }   

        [tableView deselectRowAtIndexPath: indexPath animated: YES];
    }

    return cell;
}



    -(void)nextSongPlaying:(NSNotification *)notification
    {
         //What stuff to do 
    }
4

2 回答 2

1

DShah我是这样做的..你能在我的viewDidLoad中检查它是否正确..

     [[NSNotificationCenter defaultCenter] addObserver:self 
selector:@selector(nextSongPlaying:) 
name:AVPlayerItemDidPlayToEndTimeNotification 
object:[myPlayer currentItem]];

- (void)nextSongPlaying:(NSNotification *)notification 
{ 

AVPlayerItem *playerItem = [notification object];
[playerItem seekToTime:kCMTimeZero];
[myPlayer play];
}
于 2012-08-08T11:58:05.990 回答
0

请参阅 Apple 的链接以获取帮助：http: //developer.apple.com/library/ios/#documentation/AudioVideo/Conceptual/AVFoundationPG/Articles/02_Playback.html

这个链接解释了Playing Multiple Items。您可以使用AVQueuePlayerwhich 的子类来AVPlayer对多首歌曲进行排队。

编辑

请查看 GitHub 链接：https ://github.com/crocodella/AVPlayerSample 解释：http ://www.crocodella.com.br/2011/01/using-avplayer-to-play-background-music-from-图书馆/

此链接具有您想要的相同内容。

于 2012-08-04T18:07:40.370 回答