iPhone - 沿触摸和拖动路径移动对象 [英] iPhone - Move object along touch and drag path

问题描述

我正在开发一个简单的动画，其中 UIImageView 沿 UIBezierPath 移动，现在我想提供用户交互移动 UIImageView ，以便用户可以通过触摸 UIImageView UIImageView c $ c>并在屏幕上拖动 UIImageview 。

I am developing a simple animation where an UIImageView moves along a UIBezierPath, now I want to provide user interation to the moving UIImageView so that user can guide the UIImageView by touching the UIImageView and drag the UIImageview around the screen.

推荐答案

因此，您希望用户能够沿着弯曲路径触摸关键帧动画中间的图像，并将其拖动到其他位置？你想在那个时候想要发生什么？

So you want the user to be able to touch an image in the middle of a keyframe animation along a curved path, and drag it to a different location? What do you want to happen to the animation at that point?

你有多重挑战。

首先是在关键帧动画处于飞行中时检测对象上的触摸。

First is detecting the touch on the object while a keyframe animation is "in flight".

为此，您需要使用父视图的图层的表示层的hitTest方法。

To do that, you want to use the parent view's layer's presentation layer's hitTest method.

图层的表示层表示任何给定时刻图层的状态，包括动画。

A layer's presentation layer represents the state of the layer at any given instant, including animations.

一旦检测到触摸在您的视图中，您需要从表示层获取图像的当前位置，停止动画，并使用基于touchesMoved / touchesDragged的动画接管。

Once you detect touches on your view, you will need to get the image's current location from the presentation layer, stop the animation, and take over with a touchesMoved/touchesDragged based animation.

我写的一个演示应用程序，演示如何检测沿路径设置动画的对象的触摸。这将是一个很好的起点。

I wrote a demo application that shows how to detect touches on an object that's being animated along a path. That would be a good starting point.

看看这里：

核心动画演示，包括在动画飞行中时检测视图上的触摸。

这篇关于iPhone - 沿触摸和拖动路径移动对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！