如何从 ipodlibrary 获取歌曲并使用 AVPlayer 播放

Question

我想从 ipod 库中选择歌曲并使用 avplayer 播放我希望音乐在应用程序进入后台后继续播放我是 iOS 编程新手，谁能帮帮我..

谢谢

Answer 1

要允许用户从他们的音乐库中挑选一首（或多首歌曲），请使用MPMediaPickerController 类。

-(void) pickSong {

    // Create picker view
    MPMediaPickerController* picker = [[MPMediaPickerController alloc] init];
    picker.delegate = self;

    // Check how to display
    if ([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPad) {

        // Show in popover
        [popover dismissPopoverAnimated:YES];
        popover = [[UIPopoverController alloc] initWithContentViewController:picker];
        [popover presentPopoverFromBarButtonItem:self.navigationItem.rightBarButtonItem permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];

    } else {

        // Present modally
        [self presentViewController:picker animated:YES completion:nil];

    }

}

如果您没有通过标题栏右侧的按钮显示 self.navigationItem.rightBarButtonItem，请更改它。

然后你需要通过实现委托来监听结果：

当用户取消选择时调用：

-(void) mediaPickerDidCancel:(MPMediaPickerController *)mediaPicker {

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

}

在用户选择某项时调用：

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

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

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

    // Create player item
    AVPlayerItem* playerItem = [AVPlayerItem playerItemWithAsset:asset];

    // Play it
    AVPlayer* myPlayer = [AVPlayer playerWithPlayerItem:playerItem];
    [myPlayer play]; 

}

您的类 .h 文件中需要 UIPopoverController* popover;。你也应该在某处保留myPlayer...

要让音乐在后台继续播放，请将 audio 字符串添加到 Info.plist 中 UIBackgroundModes 键下的数组中。