捕获透明UIView上的触摸

Question

I have an app that has a series of custom modal dialog views. Being modal I need to prevent users from interacting with items that are to the side of the dialogs (eg when the pause dialog appears I don't want users to be able to touch the buttons to navigate through the app). To make them modal I have a transparent UIView "behind" each of the dialog views to trap touches. This works fine except that there's a UIView animation that fades the dialogs up and while they're fading up the dialog views ignore touches.

As far as I can tell the problem is that if a UIView 's alpha is not equal to 1.0 then it ignores touches. Is there any way to have UIView with some alpha blending respond to touches?

Answer 1

如果要为对话框视图的Alpha设置动画，并且希望对话框视图在动画过程中支持交互，则在创建动画时需要使用UIViewAnimationOptionAllowUserInteraction选项。

Answer 2

The UIView doesn't ignore touches unless its alpha is 0.0, or if its 'hidden' property is set to YES. Both of these settings make the UIView invisible.

I'd suggest using a modal view controller - unless there's some reason you want the other buttons to show. You would set a separate view controller for each modal view, rather than a transparent view. Then, use the view controller's 'presentModalViewController:animated:' method to control it.

Note that modal view controllers can be nested (one can call another), so you can have more than one chained together, as needed.