iOS检测静音开关是否开启

使用AudioServicesPlaySystemSound播放一段0.2s的空白音频，并监听音频播放完成事件，如果从开始播放到回调完成方法的间隔时间小于0.1s，则意味当前静音开关为开启状态。

void SoundMuteNotificationCompletionProc(SystemSoundID  ssID,void* clientData){
    MMSoundSwitchDetector* detecotr = (__bridge MMSoundSwitchDetector*)clientData;
    [detecotr complete];
}
 
- (instancetype)init {
    self = [super init];   
     if (self) {
        NSURL *pathURL = [[NSBundle mainBundle] URLForResource:@"mute" withExtension:@"caf"];     
        if (AudioServicesCreateSystemSoundID((__bridge CFURLRef)pathURL, &_soundId) == kAudioServicesNoError){
            AudioServicesAddSystemSoundCompletion(self.soundId, CFRunLoopGetMain(), kCFRunLoopDefaultMode, SoundMuteNotificationCompletionProc,(__bridge void *)(self));
            UInt32 yes = 1;
            AudioServicesSetProperty(kAudioServicesPropertyIsUISound, sizeof(_soundId),&_soundId,sizeof(yes), &yes);
        } else {
            MMErrorWithModule(LOGMODULE, @"Create Sound Error.");
            _soundId = 0;
        }
    }    return self;
}
 
- (void)checkSoundSwitchStatus:(CheckSwitchStatusCompleteBlk)completHandler {   
         if (self.soundId == 0) {
        completHandler(YES);      
        return;
    }
    self.completeHandler = completHandler;
    self.beginTime = CACurrentMediaTime();
    AudioServicesPlaySystemSound(self.soundId);
}
 
- (void)complete {
    CFTimeInterval elapsed = CACurrentMediaTime() - self.beginTime;
    BOOL isSwitchOn = elapsed > 0.1;   
     if (self.completeHandler) {
        self.completeHandler(isSwitchOn);
    }
}