MPVolumeView AirPlay按钮未显示

Question

使用MPVolumeView，我想为应用程序的音频创建一个AirPlay输出按钮。

MPVolumeView *volumeView = [ [MPVolumeView alloc] initWithFrame:CGRectMake(20, 20, 220, 20)];
    [volumeView setShowsVolumeSlider:NO];
    [volumeView setShowsRouteButton:YES];
    [volumeView sizeToFit];
    [self.view addSubview:volumeView];
    [volumeView release];

Errors / issues none，但它没有显示，有什么想法吗？

谢谢!

Answer 1

不是初始化，而是发送initWithFrame:(CGRect)消息。似乎视图就在那里，它只有一个(0,0,0,0)的框架。

代码如下：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    ViewController *vc = [[ViewController alloc] init];
    [vc.view setBackgroundColor:[UIColor redColor]];
    MPVolumeView *volumeView = [[MPVolumeView alloc] initWithFrame:CGRectMake(20, 20, 200, 50)];
    [volumeView setShowsVolumeSlider:YES];
    [volumeView setShowsRouteButton:YES];
    [volumeView sizeToFit];
    [vc.view addSubview:volumeView];
    UILabel *testLabel = [[UILabel alloc] initWithFrame:CGRectMake(50, 50, 200, 50)];
    testLabel.text = @"TESTING";
    [vc.view addSubview:testLabel];
    [self.window setRootViewController:vc];
    [self.window makeKeyAndVisible];
    [vc viewDidLoad];
    return YES;
}

当在设备上测试时，它可以工作：

​

​

Answer 2

可能是你把你的VolumeView放在白色的背景上。Airplay路由按钮在使用之前是白色的(即:当它不是通过AirPlay路由时)，所以如果您将控件放在白色背景上，您将看不到它，但它会对轻击做出反应。将背景更改为类似于上面的红色，它就会显示出来。

Answer 3

当有多条可用路线时，会出现空中播放路线按钮。

我发现永久显示Airplay按钮的技巧是隐藏MPVolumeView路由按钮，删除用户MPVolumeView用户交互，并使用UIButton包装器定位路由按钮操作。

var airplayRouteButton: UIButton?

private func airPlayButton() -> UIButton {

    let wrapperView = UIButton(frame: CGRect(x: 0, y: 0, width: 44, height: 44))
    wrapperView.setImage(YOUR_AIRPLAY_IMAGE, for: UIControlState.normal)
    wrapperView.backgroundColor = .clear
    wrapperView.addTarget(self, action: #selector(PlayerView.replaceRouteButton), for: UIControlEvents.touchUpInside)

    let volumeView = MPVolumeView(frame: wrapperView.bounds)
    volumeView.showsVolumeSlider = false
    volumeView.showsRouteButton = false
    volumeView.isUserInteractionEnabled = false

    self.airplayRouteButton = volumeView.subviews.filter { $0 is UIButton }.first as? UIButton

    wrapperView.addSubview(volumeView)

    return wrapperView
}

@objc private func replaceRouteButton() {
    airplayRouteButton?.sendActions(for: .touchUpInside)
}