今天遇到一个ios播放声音中断后台音乐的问题，在我的app中如果调用AVAudioSession 播放完声音，后台的qq音乐偶尔不能恢复，而网易云音乐一次都不能恢复播放，研究了一下AVAudioSession ，我之前调用[audioSession setActive:NO error:&err];还有一个方法
/* Set the session active or inactive. Note that activating an audio session is a synchronous (blocking) operation.
Therefore, we recommend that applications not activate their session from a thread where a long blocking operation will be problematic.
Note that this method will throw an exception in apps linked on or after iOS 8 if the session is set inactive while it has running or
paused I/O (e.g. audio queues, players, recorders, converters, remote I/Os, etc.).
*/
- (BOOL)setActive:(BOOL)active error:(NSError **)outError;
- (BOOL)setActive:(BOOL)active withOptions:(AVAudioSessionSetActiveOptions)options error:(NSError **)outError NS_AVAILABLE_IOS(6_0);
而AVAudioSessionSetActiveOptions这个枚举
/* options for use when calling setActive:withOptions:error:
AVAudioSessionSetActiveOptionNotifyOthersOnDeactivation --
Notify an interrupted app that the interruption has ended and it may resume playback. Only valid on
session deactivation. */
typedef NS_OPTIONS(NSUInteger, AVAudioSessionSetActiveOptions)
{
AVAudioSessionSetActiveOptionNotifyOthersOnDeactivation = 1
} NS_AVAILABLE_IOS(6_0);
注释的意思是：“通知中断程序中断已经结束，可以恢复播放。。。。“，
看来这里应该是造成播放声音导致后台的qq音乐偶尔不能恢复，而网易云音乐一次都不能恢复播放的地方
之后改成调用 [[AVAudioSession sharedInstance] setActive:NO withOptions:AVAudioSessionSetActiveOptionNotifyOthersOnDeactivation error:nil];果然网易云音乐也可以恢复了，看了苹果官方的文章，上面有张图