计算机网络自顶向下第三章传输层二TCP

[[UIDevice currentDevice] setProximityMonitoringEnabled:YES];

AVAudioSession *audioSession = [AVAudioSession sharedInstance];

//默认情况下扬声器播放

[audioSession setCategory:AVAudioSessionCategoryPlayback withOptions:AVAudioSessionCategoryOptionMixWithOthers error:nil];

[audioSession setActive:YES error:nil];