iphone - 我有一个在后台播放音频的 iPad 应用程序，但应用程序图标没有出现在 ipod 控件中

Question

我的问题是 - 当我的 iPad 在后台播放音频时，“我的应用程序图标”没有出现。我正在使用 iPodMusicPlayer。为了在后台播放音频，我编写了这些代码..

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

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

- (BOOL)canBecomeFirstResponder {
        return YES;
}

//当应用程序处于后台时，iPod 控件将发送这些事件

- (void) remoteControlReceivedWithEvent: (UIEvent *) receivedEvent {
       if (receivedEvent.type == UIEventTypeRemoteControl) {
           switch (receivedEvent.subtype) {

           case UIEventSubtypeRemoteControlTogglePlayPause:
               [self performSelector:@selector(playPause:)];
               break;

           case UIEventSubtypeRemoteControlPreviousTrack:
            //[self previousSong:nil];
            //[self performSelector:@selector(previousSong:)];
            break;

           case UIEventSubtypeRemoteControlNextTrack:
               //[self performSelector:@selector(nextSong:)];
               break;
          default:
              break;
         }
     }
}

和 info.plist 我也设置了“所需的背景模式”

Answer 1

您还必须将 UIBackgroundModes 添加到您的 Info.plist 并将其值设置为 audio。

请查看 iOS 应用程序编程指南，特别是 App States and Multitasking section有关如何在后台执行任务的详细信息。

[更新]

同时将这两行添加到 application:didFinishLaunchingWithOptions: 中的 AppDelegate.m:

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

当您开始播放音频时，这段代码:

UIBackgroundTaskIdentifier newTaskId = UIBackgroundTaskInvalid;
[_player play];
newTaskId = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:NULL];

这应该可以做到。在模拟器和设备上进行了测试。