Question

我正在以这种方式为UIView子类设置 border 宽度和颜色：

- (void) setViewBorder
{
    self.layer.borderColor = [UIColor greenColor].CGColor;
    self.layer.borderWidth = 3.0f;
}

我的问题是：我该如何设置动画？感谢。

Answer 1

borderColor和borderWidth都是可动画的属性，但由于您是在UIView动画块之外的视图子类中执行此操作，因此隐式动画（更改值时自动发生的动画）将被禁用。

如果要为这些属性设置动画，则可以使用CABasicAnimation执行显式动画。由于您在同一图层上设置了两个属性的动画，因此可以将它们添加到动画组中，并仅配置一次持续时间，时间等。请注意，显式动画纯粹是可视化的，添加它们时模型值（实际属性）不会更改。这就是您配置动画和设置模型值的原因。

CABasicAnimation *color = [CABasicAnimation animationWithKeyPath:@"borderColor"];
// animate from red to blue border ...
color.fromValue = (id)[UIColor redColor].CGColor;
color.toValue   = (id)[UIColor blueColor].CGColor;
// ... and change the model value
self.layer.borderColor = [UIColor blueColor].CGColor;

CABasicAnimation *width = [CABasicAnimation animationWithKeyPath:@"borderWidth"];
// animate from 2pt to 4pt wide border ...
width.fromValue = @2;
width.toValue   = @4;
// ... and change the model value
self.layer.borderWidth = 4;

CAAnimationGroup *both = [CAAnimationGroup animation];
// animate both as a group with the duration of 0.5 seconds
both.duration   = 0.5;
both.animations = @[color, width];
// optionally add other configuration (that applies to both animations)
both.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];

[self.layer addAnimation:both forKey:@"color and width"];

如果您在“设置插值”部分下查看the documentation for CABasicAnimation，您将看到没有必要像我一样指定toValue和fromValue，因此可以稍微缩短代码。但是，为了清晰和可读性（特别是当您开始使用Core Animation时）更明确可以帮助您（和您的同事）理解代码。

Answer 2

这是@David回答的快速解决方案：

let colorAnimation = CABasicAnimation(keyPath: "borderColor")
colorAnimation.fromValue = UIColor.red.cgColor
colorAnimation.toValue = UIColor.blue.cgColor
view.layer.borderColor = UIColor.blue.cgColor

let widthAnimation = CABasicAnimation(keyPath: "borderWidth")
widthAnimation.fromValue = 2
widthAnimation.toValue = 4
widthAnimation.duration = 4
view.layer.borderWidth = 4

let bothAnimations = CAAnimationGroup()
bothAnimations.duration = 0.5
bothAnimations.animations = [colorAnimation, widthAnimation]
bothAnimations.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)

view.layer.add(bothAnimations, forKey: "color and width")

Answer 3

如果你只想淡出边框，你也可以这样做：

UIView.transition(with: self, duration: 0.3, options: .transitionCrossDissolve, animations: {

        self.layer.borderColor = UIColor.green.cgColor
        self.layer.borderWidth = 3

}, completion: nil)

Answer 4

您可以创建关键帧动画，将其添加到视图中。

//Create animation
        CAKeyframeAnimation *colorsAnimation = [CAKeyframeAnimation animationWithKeyPath:@"borderColor"];
        colorsAnimation.values = [NSArray arrayWithObjects: (id)[UIColor greenColor].CGColor,
                                  (id)[UIColor yellowColor].CGColor, nil];
        colorsAnimation.keyTimes = [NSArray arrayWithObjects:[NSNumber numberWithFloat:0.25],[NSNumber numberWithFloat:1.0], nil];
        colorsAnimation.calculationMode = kCAAnimationLinear;
        colorsAnimation.removedOnCompletion = NO;
        colorsAnimation.fillMode = kCAFillModeForwards;
        colorsAnimation.duration = 3.0f;

    //Create animation
    CAKeyframeAnimation *sizeAnimation = [CAKeyframeAnimation animationWithKeyPath:@"borderWidth"];
    sizeAnimation.values = [NSArray arrayWithObjects:[NSNumber numberWithFloat:0.0],
                             [NSNumber numberWithFloat:5.0], nil];
    sizeAnimation.keyTimes = [NSArray arrayWithObjects:[NSNumber numberWithFloat:0.0],[NSNumber numberWithFloat:3.0], nil];
    sizeAnimation.calculationMode = kCAAnimationLinear;
    sizeAnimation.removedOnCompletion = NO;
    sizeAnimation.fillMode = kCAFillModeForwards;
    sizeAnimation.duration = 3.0f;

    //Add animation
    [yoursubview.layer   addAnimation:colorsAnimation forKey:nil];
    [yoursubview.layer   addAnimation:sizeAnimation forKey:nil];

动画CALayer边框更改

4 个答案: