CABasicAnimation当前经过的时间 [英] CABasicAnimation current elapsed time

问题描述

我只是从一个笨拙的while循环中重写了一个很大的动画（触发drawRect：x次），这是我无法弄清的最后一件事。

I just rewrote quite a big animation from a dumb while loop (firing drawRect: x times) and this is the last thing that I just can't figure out..

如何获取动画的当前经过时间？我知道如何获取当前的CFTimeInterval（是否可以暂停CABasicAnimation？）：

How can I get the current elapsed time of my animation? I know how to get the current CFTimeInterval (Is there a way to pause a CABasicAnimation?):

CFTimeInterval currentTime = [self.multiplierLayer convertTime:CACurrentMediaTime() fromLayer:nil];

但是从动画开始的那一刻起，我该如何使用它来计算当前经过的时间呢？似乎beginTime始终为0.0，我必须设置动画开始的那一刻，然后从beginTime中提取currentTime吗？

But how can I use this to calculate the current elapsed time from the moment my animation started? It seems that beginTime is always 0.0, do I have to set that the moment my animation starts and then extract the currentTime from the beginTime?

很抱歉，很容易被忽略，我昨天才开始使用Core Animation。 ：）

I'm sorry if it's something simple that I'm overlooking, I just started using Core Animation yesterday. :)

编辑：
设置beginTime不是不是的操作方式，实际上

Setting beginTime is not the way to do it, really at a loss here.

推荐答案

一种可能更简单的方法是，当您创建CABasicAnimation明确设置开始时间时，例如：

A possibly easier way to do what you want is when you create your CABasicAnimation explicitly set the starting time, like:

basicAnimation.beginTime = CACurrentMediaTime();

以后，您可以找出花费了多少时间：

Later on you can figure out how much time has elapsed with:

CFTimeInterval elapsedTime = CACurrentMediaTime() - basicAnimation.beginTime;

并通过以下方式获得百分比：

And get the percentage through with:

progress = elapsedTime / basicAnimation.duration;

（如果您有timeOffset或类似的东西，代码会稍微复杂一些。）

(The code will be slightly more complex if you have a timeOffset or something like that.)

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