1 [[UIDevice currentDevice] setProximityMonitoringEnabled:YES]; //建议在播放之前设置yes，播放结束设置NO，这个功能是开启红外感应 2  3 //添加监听 4     [[NSNotificationCenter defaultCenter] addObserver:self 5                                              selector:@selector(sensorStateChange:) 6                                                  name:@"UIDeviceProximityStateDidChangeNotification" 7                                                object:nil]; 8  9 //处理监听触发事件10 -(void)sensorStateChange:(NSNotificationCenter *)notification;11 {12     //如果此时手机靠近面部放在耳朵旁，那么声音将通过听筒输出，并将屏幕变暗（省电啊）13     if ([[UIDevice currentDevice] proximityState] == YES)14     {15         NSLog(@"Device is close to user");16         [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];17        18     }19     else20     {21         NSLog(@"Device is not close to user");22         [[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];23     }24 }25 26 27 //初始化播放器的时候如下设置28  UInt32 sessionCategory = kAudioSessionCategory_MediaPlayback;29     AudioSessionSetProperty(kAudioSessionProperty_AudioCategory,30                             sizeof(sessionCategory),31                             &sessionCategory);   32    33     UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_Speaker;34     AudioSessionSetProperty (kAudioSessionProperty_OverrideAudioRoute,35                              sizeof (audioRouteOverride),36                              &audioRouteOverride);37    38     AVAudioSession *audioSession = [AVAudioSession sharedInstance];39     //默认情况下扬声器播放40     [audioSession setCategory:AVAudioSessionCategoryPlayback error:nil];41     [audioSession setActive:YES error:nil];