swift - 透明度(alpha)从 swift 的第二次运行中被删除

Question

我通过以下代码加载 subview :

HideView.backgroundColor = UIColor.clearColor()
var loadingView = UIView (frame: CGRectMake(120, 190, 90, 90));
loadingView.center = HideView.center
loadingView.backgroundColor = UIColor(red:0.76, green:0.76, blue:0.76, alpha:0.9)
loadingView.clipsToBounds = true;
loadingView.layer.cornerRadius = 10.0
loadingView.layer.shouldRasterize = true
HideView.addSubview(loadingView)

上面的代码运行正常，我们可以看到背景如下:

但是当此屏幕 subview 再次出现时(从第二次开始)透明度消失，如下所示:

Answer 1

您将“loadingView”两次添加到“HiddenView”中。这就是为什么它在第二次运行时看起来被阻止了。

相反，请确保只添加一次。

HideView.backgroundColor = UIColor.clearColor()
if (!addedLoadingView) { // Or anything alike...
    addedLoadingView = YES
    var loadingView = UIView (frame: CGRectMake(120, 190, 90, 90));
    loadingView.center = HideView.center
    loadingView.backgroundColor = UIColor(red:0.76, green:0.76, blue:0.76, alpha:0.9)
    loadingView.clipsToBounds = true;
    loadingView.layer.cornerRadius = 10.0
    loadingView.layer.shouldRasterize = true
    HideView.addSubview(loadingView)
}