具有非矩形范围的UIDynamicItem [英] UIDynamicItem with non-rectangular bounds

问题描述

所以我正在研究UIKit Dynamics，我遇到的一个问题是，如果我想使用自定义的drawRect:创建一个UIView(例如，假设我要绘制一个三角形)，似乎有无法指定要用于UICollisionBehavior的UIView(或UIDynamicItem)的路径.

So I'm looking into UIKit Dynamics and the one problem I have run into is if I want to create a UIView with a custom drawRect: (for instance let's say I want to draw a triangle), there seems to be no way to specify the path of the UIView (or rather the UIDynamicItem) to be used for a UICollisionBehavior.

我的目标确实是使屏幕上的多边形彼此碰撞，而碰撞的方式恰恰是人们所期望的.

My goal really is to have polygons on the screen that collide with one another exactly how one would expect.

我想出了一种将多个视图拼接在一起的解决方案，但这似乎对我想要的东西来说是过大了.

I came up with a solution of stitching multiple views together but this seems like overkill for what I want.

是否有一些简单的方法可以做到这一点，或者我真的必须将视图拼接在一起吗?

Is there some easy way to do this, or do I really have to stitch views together?

丹

推荐答案

观看有关此主题的WWDC 2013视频.它们非常清楚:为了提高效率和速度，在碰撞期间仅视域的(矩形)边界很重要.

Watch the WWDC 2013 videos on this topic. They are very clear: for the sake of efficiency and speed, only the (rectangular) bounds of the view matter during collisions.

编辑，在iOS 9中，动态项目可以具有自定义的碰撞边界.您可以具有由框架决定的矩形，由框架决定的椭圆或自定义形状-逆时针凸的简单封闭UIBezierPath.相关属性collisionBoundsType和(对于自定义形状)collisionBoundingPath是只读的，因此您必须子类化才能设置它们.

EDIT In iOS 9, a dynamic item can have a customized collision boundary. You can have a rectangle dictated by the frame, an ellipse dictated by the frame, or a custom shape — a convex counterclockwise simple closed UIBezierPath. The relevant properties, collisionBoundsType and (for a custom shape) collisionBoundingPath, are read-only, so you will have to subclass in order to set them.

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