iOS动画-CAAnimation的说明与简单使用

CAAnimation是QuartzCore框架里面定义的

CAAnimation主要是遵循了 CAMediaTiming 协议，拥有了一些动画的属性

一些常用的animationWithKeyPath值的总结

核心动画Core Animation常用类的继承关系

CAMediaTiming只有这两个代理方法 顾名思义，一个开始一个结束，CAAnimation实现代理方法不同于其他，CAAnimation不用声明CAAnimationDelegate。直接重写方法即可

/* Delegate methods for CAAnimation. */

@protocol CAAnimationDelegate <NSObject>
@optional

/* Called when the animation begins its active duration. */
//动画的开始的回调
- (void)animationDidStart:(CAAnimation *)anim;

/* Called when the animation either completes its active duration or
 * is removed from the object it is attached to (i.e. the layer). 'flag'
 * is true if the animation reached the end of its active duration
 * without being removed. */
//动画结束的回调 。flag参数表明了动画是自然结束还是被打断的
- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag;

@end

1.CABasicAnimation
通过设定起始点，终点，时间，动画会沿着你这设定点进行移动。可以看做特殊的CAKeyFrameAnimation
2.CAKeyframeAnimation
Keyframe顾名思义就是关键点的frame，你可以通过设定CALayer的始点、中间关键点、终点的frame，时间，动画会沿你设定的轨迹进行移动
3.CAAnimationGroup
Group也就是组合的意思，就是把对这个Layer的所有动画都组合起来。PS：一个layer设定了很多动画，他们都会同时执行，
4.CATransition
这个就是苹果帮开发者封装好的一些动画，

KeyFrame的意思是关键帧，所谓“关键”就是改变物体运动趋势的帧，在该点处物体将发生运动状态，比如矩形的四个角，抛物线的顶点等。

values 指明整个动画过程中的关键帧点
path 与values属性一样，同样是用于指定整个动画所经过的路径的。需要注意的是，values与path是互斥的，当values与path同时指定时，path会覆盖values，即values属性将被忽略。
keyTimes 是一个数组，用以指定每个子路径(AB,BC,CD)的时间。如果你没有显式地对keyTimes进行设置，则系统会默认每条子路径的时间为：ti=duration/(5-1)，即每条子路径的duration相等，都为duration的1\4。当然，我们也可以传个数组让物体快慢结合。例如，你可以传入{0.0, 0.1,0.6,0.7,1.0}，其中首尾必须分别是0和1，因此tAB=0.1-0, tCB=0.6-0.1, tDC=0.7-0.6, tED=1-0.7.....
timeFunctions 这个属性用以指定时间函数，类似于运动的加速度，有以下几种类型。记住，这是一个数组，你有几个子路径就应该传入几个元素
/** Timing function names. **/

CA_EXTERN NSString * const kCAMediaTimingFunctionLinear
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0);//默认，匀速执行动画
CA_EXTERN NSString * const kCAMediaTimingFunctionEaseIn
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0);//浅入，先慢慢加速，后突然停止
CA_EXTERN NSString * const kCAMediaTimingFunctionEaseOut
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0);//先全速开始，再慢慢减速停止
CA_EXTERN NSString * const kCAMediaTimingFunctionEaseInEaseOut
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0);//浅入浅出，先慢慢加速，再慢慢减速
CA_EXTERN NSString * const kCAMediaTimingFunctionDefault
    CA_AVAILABLE_STARTING (10.6, 3.0, 9.0, 2.0);//效果同KCAMediaTimingFuncationEaseInEaseOut

calculationMode 该属性决定了物体在每个子路径下是跳着走还是匀速走，跟timeFunctions属性有点类似

/* `calculationMode' strings. */

CA_EXTERN CAAnimationCalculationMode const kCAAnimationLinear
    API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0));//线性，默认
CA_EXTERN CAAnimationCalculationMode const kCAAnimationDiscrete
    API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0));//离散，无中间过程，但keyTimes设置的时间依旧生效，物体跳跃的出现在各个关键帧上
CA_EXTERN CAAnimationCalculationMode const kCAAnimationPaced
    API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0));//平均，keyTimes和Timing functions设置失效
CA_EXTERN CAAnimationCalculationMode const kCAAnimationCubic
    API_AVAILABLE(macos(10.7), ios(4.0), watchos(2.0), tvos(9.0));//平均，同上
CA_EXTERN CAAnimationCalculationMode const kCAAnimationCubicPaced
    API_AVAILABLE(macos(10.7), ios(4.0), watchos(2.0), tvos(9.0));//平均，同上

/* `rotationMode' strings. */

CA_EXTERN CAAnimationRotationMode const kCAAnimationRotateAuto
    API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0));
CA_EXTERN CAAnimationRotationMode const kCAAnimationRotateAutoReverse
    API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0));

示例

实现水波动画

- (void)drawRect:(CGRect)rect {
     //新建动画数组
    CALayer *animationLayer = [CALayer layer];
    CAAnimationGroup *animationGroup = [self animationGroupAnimations:[self animationArray]];
    CALayer *pulsingLayer = [self pulsingLayer:rect animationGroup:animationGroup];
    //将动画 Layer 添加到 animationLayer
    [animationLayer addSublayer:pulsingLayer];
    
    // 新建缩放动画
    CABasicAnimation *animationTwo = [self oppositeScaleAnimation];
    // 新建一个动画 Layer，将动画添加上去
    CALayer *pulsingLayerTwo = [self pulsingLayer:rect animation:animationTwo];
    //将动画 Layer 添加到 animationLayer
    [animationLayer addSublayer:pulsingLayerTwo];
    [self.layer addSublayer:animationLayer];
}

- (CALayer *)pulsingLayer:(CGRect)rect animation:(CABasicAnimation *)animation {
    CALayer *pulsingLayer = [CALayer layer];
    pulsingLayer.borderWidth = 0.5;
    pulsingLayer.borderColor = [[UIColor whiteColor]colorWithAlphaComponent:0.4].CGColor;
    pulsingLayer.frame = CGRectMake(0, 0, rect.size.width, rect.size.height);
    pulsingLayer.cornerRadius = rect.size.height / 2;
    [pulsingLayer addAnimation:animation forKey:@"plulsing"];
    return pulsingLayer;
}

- (CALayer *)pulsingLayer:(CGRect)rect animationGroup:(CAAnimationGroup *)animationGroup {
    CALayer *pulsingLayer = [CALayer layer];
    pulsingLayer.borderWidth = 1;
    pulsingLayer.borderColor = [[UIColor whiteColor]colorWithAlphaComponent:0.4].CGColor;
    pulsingLayer.frame = CGRectMake(0, 0, rect.size.width, rect.size.height);
    pulsingLayer.cornerRadius = rect.size.height / 2;
    [pulsingLayer addAnimation:animationGroup forKey:@"plulsing"];

    return pulsingLayer;
}

- (CAAnimationGroup *)animationGroupAnimations:(NSArray *)array {
    CAAnimationGroup *animationGroup = [CAAnimationGroup animation];
    animationGroup.beginTime = CACurrentMediaTime();
    animationGroup.duration = 2;
    animationGroup.repeatCount = 2;
    animationGroup.autoreverses = YES;//动画结束时是否执行逆动画
    animationGroup.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionDefault];//设置动画的速度变化:淡出
    animationGroup.removedOnCompletion
    return animationGroup;
}


- (NSArray *)animationArray {
    NSArray *animationArray = nil;
    CABasicAnimation *scaleAnimation = [self scaleAnimation];
    CAKeyframeAnimation *borderColorAnimation = [self borderColorAnimation];
    animationArray = @[scaleAnimation, borderColorAnimation];
    return animationArray;
}

- (CABasicAnimation *)scaleAnimation {
    CABasicAnimation *scaleAnimation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
     
    scaleAnimation.fromValue = @1;
    scaleAnimation.toValue = @3;
    return scaleAnimation;
} 

- (CABasicAnimation *)oppositeScaleAnimation {
    CABasicAnimation *scaleAnimation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
    scaleAnimation.fromValue = @1;
    scaleAnimation.toValue = @0.7;
    scaleAnimation.beginTime = CACurrentMediaTime();
    scaleAnimation.duration = 2;
    scaleAnimation.repeatCount = 2;
    scaleAnimation.autoreverses = YES;//动画结束时是否执行逆动画
    scaleAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];//设置动画的速度变化:淡出
    return scaleAnimation;
}

- (CAKeyframeAnimation *)borderColorAnimation {
    CAKeyframeAnimation *borderColorAnimation = [CAKeyframeAnimation animation];
    borderColorAnimation.keyPath = @"borderColor";
    borderColorAnimation.values = @[
        (__bridge id)[[UIColor whiteColor]colorWithAlphaComponent:0.4].CGColor,
        (__bridge id)[[UIColor whiteColor]colorWithAlphaComponent:0.3].CGColor,
        (__bridge id)[[UIColor whiteColor]colorWithAlphaComponent:0.2].CGColor,
        (__bridge id)[[UIColor whiteColor]colorWithAlphaComponent:0.1].CGColor,
        (__bridge id)[[UIColor whiteColor]colorWithAlphaComponent:0.0].CGColor];
    borderColorAnimation.keyTimes = @[@0.2,@0.4,@0.6,@0.8,@1
    ];
    return borderColorAnimation;
}

引用、借鉴

iOS动画-CAAnimation使用详解https://www.jianshu.com/p/c22918a5e7ca
简书发表文章格式（MakrDwon使用）https://www.jianshu.com/p/0e63982d7a98