iphone - 如何在 AVPlayer 中播放完第一首歌曲后继续播放第二首歌曲

Question

如何使用 AVPlayer 立即开始下一首歌曲？我从 MPMediaItemCollection 中的 iPod 库中选择了歌曲集，显示在我的 UITableView [myPlaylistTable] 中。我知道我必须使用 NSNotification 来检查歌曲是否播放完毕，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

如果有人能帮助我解决问题，我将不胜感激。 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 
    }

Answer 1

DShah 我是这样做的..你能检查它在我的 viewDidLoad 中是否正确吗..

     [[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];
}