Question

IOS-编码！

此代码用于动画小红方以绘制大符号＆＃34; 8＆＃34;在UIView上。首先是上环（animSequence1 = 5秒），然后是下环（animSequence2 =另外5秒）。
不需要延迟！
但我坚持两个连续动画之间的奇怪延迟（约1秒）。这种延迟是从哪里来的？！？

代码：

- (void)drawRect:(CGRect)drawRect {
   CGContextRef context = UIGraphicsGetCurrentContext();
   drawRect = CGRectMake(0, 0, 320, 320);
   CGContextSetFillColorWithColor(context, [UIColor blueColor].CGColor;);
   CGContextFillRect(context, drawRect);

   // Little red square
   CALayer *layerTest;
   layerTest = [CALayer layer];
   layerTest.bounds = CGRectMake(0, 0, 20, 20);
   layerTest.anchorPoint = CGPointMake(0, 0);
   layerTest.backgroundColor = [UIColor redColor].CGColor;
   [[self layer] addSublayer:layerTest];

   // Upper ring
   CAKeyframeAnimation *animSequence1;
   animSequence1 = [CAKeyframeAnimation animationWithKeyPath:@"position"];
   animSequence1.fillMode = kCAFillModeForwards;
   animSequence1.removedOnCompletion = NO;
   animSequence1.autoreverses = NO;
   animSequence1.repeatCount = 0;
   animSequence1.duration = 5.0;
   animSequence1.beginTime = 0.0;
   animSequence1.path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(200, 120) radius:80 startAngle:DEG_TO_RAD(90) endAngle:DEG_TO_RAD(450) clockwise:YES].CGPath;
   animSequence1.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];

   // Lower ring
   CAKeyframeAnimation *animSequence2;
   animSequence2 = [CAKeyframeAnimation animationWithKeyPath:@"position"];
   animSequence2.fillMode = kCAFillModeForwards;
   animSequence2.removedOnCompletion = NO;
   animSequence2.autoreverses = NO;
   animSequence2.repeatCount = 0;
   animSequence2.duration = 5.0;
   animSequence2.beginTime = 5.0;
   animSequence2.path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(200, 280) radius:80 startAngle:DEG_TO_RAD(-90) endAngle:DEG_TO_RAD(-450) clockwise:NO].CGPath;
   animSequence2.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];

   // A sequence of animations
   CAAnimationGroup *animGroup;
   layerTest.position = CGPointMake(200, 200);
   animGroup = [CAAnimationGroup animation];
   animGroup.duration = 10.0;
   animGroup.animations = [NSArray arrayWithObjects:animSequence1, animSequence2, nil];

   [layerTest addAnimation:animGroup forKey:nil];
}

我也试过没有CAAnimationGroup 为第一个[animSequence1 setDelegate:self];（CAKeyframeAnimation）设置animSequence1，然后按CAKeyframeAnimation开始第二个animSequence2（(void)animationDidStop）。
它工作原理相同，但两个动画之间的这种奇怪的延迟（大约1秒）没有消失！

问题：如何消除两个连续CAKeyframeAnimation动画之间的奇怪延迟？ 不需要延迟！

Answer 1

不要在-drawRect:中创建图层或动画 - 您无法控制何时调用它们，因此您最终会添加多个layerTest s在你看来，所有人都试图单独制作动画。在初始化程序中创建图层/动画，或者响应某些用户交互。

我还建议您删除fillMode上的removedOnCompletion和animSequence1设置;一旦animSequence2启动，您就会有效地要求CA在同一属性上运行两次非加法动画。不确定这种行为是否定义明确，但它是另一个可能来自古怪的地方。

如何消除两个连续的CAKeyframeAnimation动画之间的奇怪延迟？

1 个答案: