检测iOS中静音模式的状态

Question

我有一个应用程序使用 AudioServicesPlaySystemSound(1104) 方法在某些点击事件上播放声音。它响应静音模式和非静音模式的状态，并相应地静音。

但是，无论振动开关处于什么状态，AudioServicesPlaySystemSound(1150) 都会播放。

如何检查振动模式的状态，以便在用户期望的时候静音？

谢谢

Answer 1

似乎有一个开源项目可以做到这一点。见here for the code and a sample project。 RBDMuteSwitch 是这里的关键类。您使用它（作为单例），并将您的班级设置为RDBMuteSwitch 的代表，以获取有关开关状态的通知。您会在切换更改或第一次致电[[RBDMuteSwitch sharedInstance] detectMuteSwitch] 时收到通知。在 iOS 9 上测试。

这是 RBDMuteSwitch.m 的重要内容，以防 github 链接失效：

- (void)playbackComplete {
    if ([(id)self.delegate respondsToSelector:@selector(isMuted:)]) {
        // If playback is far less than 100ms then we know the device is muted
        if (soundDuration < 0.010) {
            [delegate isMuted:YES];
        }
        else {
            [delegate isMuted:NO];
        }
    }
    [playbackTimer invalidate];
}

static void soundCompletionCallback (SystemSoundID mySSID, void* myself) {
    AudioServicesRemoveSystemSoundCompletion (mySSID);
    [[RBDMuteSwitch sharedInstance] playbackComplete];
}

- (void)incrementTimer {
    soundDuration = soundDuration + 0.001;
}

- (void)detectMuteSwitch {
#if TARGET_IPHONE_SIMULATOR
    // The simulator doesn't support detection and can cause a crash so always return muted
    if ([(id)self.delegate respondsToSelector:@selector(isMuted:)]) {
        [self.delegate isMuted:YES];
    }
    return;
#endif

#if __IPHONE_5_0 <= __IPHONE_OS_VERSION_MAX_ALLOWED
    // iOS 5+ doesn't allow mute switch detection using state length detection
    // So we need to play a blank 100ms file and detect the playback length
    soundDuration = 0.0;
    CFURLRef        soundFileURLRef;
    SystemSoundID   soundFileObject;

    // Get the main bundle for the app
    CFBundleRef mainBundle = CFBundleGetMainBundle();

    // Get the URL to the sound file to play
    soundFileURLRef  =  CFBundleCopyResourceURL(mainBundle,
                                                CFSTR ("detection"),
                                                CFSTR ("aiff"),
                                                NULL);

    // Create a system sound object representing the sound file
    AudioServicesCreateSystemSoundID (soundFileURLRef,
                                      &soundFileObject);

    AudioServicesAddSystemSoundCompletion (soundFileObject,NULL,NULL,
                                           soundCompletionCallback,
                                           (void*) self);

    // Start the playback timer
    playbackTimer = [NSTimer scheduledTimerWithTimeInterval:0.001 target:self selector:@selector(incrementTimer) userInfo:nil repeats:YES];
    // Play the sound
    AudioServicesPlaySystemSound(soundFileObject);
    return;
#else
    // This method doesn't work under iOS 5+
    CFStringRef state;
    UInt32 propertySize = sizeof(CFStringRef);
    AudioSessionInitialize(NULL, NULL, NULL, NULL);
    AudioSessionGetProperty(kAudioSessionProperty_AudioRoute, &propertySize, &state);
    if(CFStringGetLength(state) > 0) {
        if ([(id)self.delegate respondsToSelector:@selector(isMuted:)]) {
            [self.delegate isMuted:NO];
        }
    }
    if ([(id)self.delegate respondsToSelector:@selector(isMuted:)]) {
        [self.delegate isMuted:YES];
    }
    return;
#endif
}

本质上，代码所做的是调用AudioServicesPlaySystemSound() 获取已知持续时间的无声声音片段，并测试播放需要多长时间。如果播放持续时间小于预期时间，则表示静音开关已打开。