//处理监听触发事件 -(void)sensorStateChange:(NSNotificationCenter *)notification; { //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) if
([[UIDevice currentDevice] proximityState] == YES) { NSLog(@"Device
is close to user"); [[AVAudioSession
sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord
error:nil]; } else { NSLog(@"Device
is not close to user"); [[AVAudioSession
sharedInstance] setCategory:AVAudioSessionCategoryPlayback
error:nil]; } }