Question

我已经开始在我的应用中使用MPVolumeView，但Air Play按钮根本不显示。即使我有多个Air Play设备可用于将AVPlayer音频发送到网络上。例如，如果从控制中心检查Air Play，可以看到这些。

这是我的代码：

myVolumeView = [MPVolumeView new];
[myVolumeView setShowsVolumeSlider:YES];
[myVolumeView setShowsRouteButton:YES];
myVolumeView.frame = _volumePanel.bounds;
[myVolumeView sizeToFit];
_myVolumeView.autoresizingMask = UIAutoresizingFlexibleWidth;
[_volumePanel addSubview:myVolumeView];

非常简单的东西。我有AVPlayer运行一些音乐，就是这样。有趣的是，如果我从控制中心选择另一个Air Play设备，它会强制Air Play按钮显示在我MPVolumeView的应用程序中，但这有点不好。

如果在Xcode中我单击控制台上方的Debug Hierarchy Mode按钮，我可以在我的UI中看到Air Play按钮，但它的Alpha是0。

Answer 1

它是一个完整而彻底的黑客但它有效

   MPVolumeView* airplayButton = [[MPVolumeView alloc] init];

   for (UIButton *button in airplayButton.subviews)
    {
        if ([button isKindOfClass:[UIButton class]])
        {
            [button addObserver:self forKeyPath:@"alpha" options:NSKeyValueObservingOptionNew context:nil];
        }
    }

然后在观察者中

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if ([object isKindOfClass:[UIButton class]] && [[change valueForKey:NSKeyValueChangeNewKey] intValue] != 1)
    {
        UIButton *airplay = (UIButton *)object;
        [airplay setAlpha:1.0];
    }
}

不要忘记在dealloc中关闭观察者

- (void)dealloc
{    
    for (UIButton *button in _airplayButton.subviews)
    {
        if ([button isKindOfClass:[UIButton class]])
        {
            [button removeObserver:self forKeyPath:@"alpha"];
            break;
        }
    }
}

Answer 2

[快速版本]

创建以下功能：

    func fixAirPlayButton() {
        guard let routeButton = airPlayButton.subviews.filter({$0 is UIButton}).first else { return }
        routeButton.addObserver(self, forKeyPath: "alpha", options: .new, context: nil)
    }

    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey: Any]?, context: UnsafeMutableRawPointer?) {
        guard let btnObject = object as? UIButton, let change = change else { return}
        guard let newChange = change[NSKeyValueChangeKey.newKey] as? Int, newChange != 1 else { return }
        btnObject.alpha = 1.0
    }

    func removeAirPlayButtonFix() {
        guard let routeButton = airPlayButton.subviews.filter({$0 is UIButton}).first else { return }
        routeButton.removeObserver(self, forKeyPath: "alpha")
    }

并在需要时使用它们，例如：

    let airPlayButton = MPVolumeView(frame: .zero)

    override func viewDidLoad() {
        super.viewDidLoad()
        fixAirPlayButton()
    }

    deinit {
        removeAirPlayButtonFix()
    }

MPVolumeView AirPlay按钮不可见

2 个答案: