呈现一个透明的模态 UIViewController [英] Present a transparent modal UIViewController

问题描述

我正在尝试自己制作一个自定义的 alertView(适用于 iOS7+)，但我在使用 alertView 演示文稿时遇到了困难.

I'm trying to make a custom alertView (for iOS7+) on my own but I struggle with the alertView presentation.

我有一个黑色背景的 UIViewController(alpha 设置为 0.25f)，以及一个作为子视图的 alertView.

I have a UIViewController with a black background (alpha set to 0.25f), and a alertView as subview.

当我想显示 alertView 时，我以模态呈现 viewController:

When I want to show the alertView, I present modally the viewController:

-(void) show 
{
    UIWindow* window = [[UIApplication sharedApplication] keyWindow];
    self.modalTransitionStyle = UIModalPresentationCustom;
    self.transitioningDelegate = self;
    [window.rootViewController presentViewController:self animated:YES completion:nil];
}

这是我的动画对象:

-(NSTimeInterval) transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext
{
    NSLog(@"%s",__PRETTY_FUNCTION__);
    return 2;
}

-(void) animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
    NSLog(@"%s",__PRETTY_FUNCTION__);

    UIView* toView = [transitionContext viewForKey:UITransitionContextToViewKey];
    toView.alpha = 0;

    UIView* container = [transitionContext containerView];
    [container addSubview:toView];

    [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
        toView.alpha = 0.5;
    } completion:^(BOOL finished) {
        [transitionContext completeTransition:YES];
    }];
}

问题是:模态 VC 正像它应该做的那样随着背景中的呈现 VC 逐渐消失，但是当动画结束时，呈现的 VC 会从背景中移除.

The thing is: the modal VC is fading with the presenting VC in background as its supposed to do, but when the animation ends the presenting VC is removed from the background.

如果我调用 [transitionContext completeTransition:YES]; 代替，呈现的 VC 在后台但模态 VC 在动画结束时被删除，所以我猜如果我们发送 '不'.

If I call [transitionContext completeTransition:YES]; instead, the presenting VC is in background but the modal VC is removed at animation end, so I guess the context cancels the presentation if we send 'NO'.

有没有办法让展示的 VC 保持在后台，而不必对其进行快照并将其设置为模态 VC 视图的背景?

Is there a way to keep the presenting VC in background without having to make a snapshot of it and set it as background of the modal VC's view?

推荐答案

供您参考，我终于让我的自定义 alertView 成为弹出部分"的 UIView 的子类.为了显示它，我只是将 alertView 添加为 keyWindow 的子视图，并带有将其居中的约束，并在其后面放置一个透明的黑色背景视图.

For your information, I finally made my custom alertView a subclass of UIView for the "popUp part". To show it, I just add the alertView as subview of the keyWindow with the constraints to center it, and put a transparent black background view behind it.

由于它不是控制器，我必须自己管理 UI 旋转(仅适用于 iOS 7，它与 iOS 8 中的 UI 旋转良好).

As it's not a controller, I have to manage UI rotation by myself (only for iOS 7, it rotates well with the UI in iOS 8).

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