Question

我正在尝试为图层的位置设置动画。它动画，但它的帧属性在动画结束时不会更新，似乎只有它的presentationLayer。这就是我正在做的事情：

CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint   (path, NULL, layer.frame.origin.x, layer.frame.origin.y);
CGPathAddLineToPoint(path, NULL, 20,  20);
CGPathAddLineToPoint(path, NULL, 20,  460);
CGPathAddLineToPoint(path, NULL, 300, 460);

CAKeyframeAnimation* animation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
animation.path = path;
animation.calculationMode = kCAAnimationPaced;
animation.repeatCount = 0;
animation.autoreverses = NO;

CAAnimationGroup *theGroup = [CAAnimationGroup animation];
theGroup.animations = [NSArray arrayWithObject:animation];
theGroup.timingFunction=[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
theGroup.duration = 2;
theGroup.removedOnCompletion = NO;
theGroup.fillMode = kCAFillModeForwards;
CFRelease(path);

[layer addAnimation:theGroup forKey:@"animatePosition"];

动画完成后，图层位于正确的目的地，但是当我查询其帧值时，它表示它仍处于原始位置！何时/何地/如何使frame属性与图层的presentationLayer框架属性同步？

由于

Answer 1

动画实际上不会更改底层的任何值。要在最后一行之后立即更新实际帧值，只需将帧设置为新值即可。然后你可以摆脱removedOnCompletion = NO;

只要动画不是附加的，动画就会根据您输入的数据运行，在动画完成之前，设置实际的帧对显示没有任何影响。

在CAKeyframeAnimation之后，Layer.frame没有更新？

1 个答案: