最终效果
实现思路
动画的表现形式是颜色以及大小的变化，整体效果可以看做多个单独的波纹效果的叠加。因此我们可以创建多个CALayer，分别赋予CABasicAnimation动画，组成最终的动画效果。
因此我们先从单个波纹扩散效果来尝试，然后根据时间差将效果叠加起来。
代码
1.新建动画 View RippleAnimationView，动画效果在animationLayer上实现。
新建RippleAnimationView类，继承自UIView，设置扩散倍数，然后重写- (void)drawRect:(CGRect)rect方法，在方法内部新建承载动画的animationLayer。
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | # import @ interface RippleAnimationView : UIView /** 设置扩散倍数。默认1.423倍 */ @property (nonatomic, assign) CGFloat multiple; - (instancetype)initWithFrame:(CGRect)frame; @end @implementation RippleAnimationView - (instancetype)initWithFrame:(CGRect)frame { self = [ super initWithFrame:frame]; if (self) { self.backgroundColor = [UIColor clearColor]; _multiple = 1.423 ; } return self; } - ( void )drawRect:(CGRect)rect { CALayer *animationLayer = [CALayer layer]; // 加入动画 [self.layer addSublayer:animationLayer]; } |
2.创建单个扩散的动画承载CALayer，实现扩散效果。
首先实现缩放动画
| 1 2 3 4 5 6 7 8 9 10 | - (CABasicAnimation *)scaleAnimation { CABasicAnimation *scaleAnimation = [CABasicAnimation animationWithKeyPath:@ "transform.scale" ]; scaleAnimation.fromValue = @ 1 ; scaleAnimation.toValue = @(_multiple); scaleAnimation.beginTime = CACurrentMediaTime(); scaleAnimation.duration = 3 ; scaleAnimation.repeatCount = HUGE; // 重复次数设置为无限 return scaleAnimation; } |
新建CALayer，并在layer上加载动画。然后将这个Layer放在animationLayer上。
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | - ( void )drawRect:(CGRect)rect { CALayer *animationLayer = [CALayer layer]; // 新建缩放动画 CABasicAnimation *animation = [self scaleAnimation]; // 新建一个动画 Layer，将动画添加上去 CALayer *pulsingLayer = [self pulsingLayer:rect animation:animation]; //将动画 Layer 添加到 animationLayer [animationLayer addSublayer:pulsingLayer]; [self.layer addSublayer:animationLayer]; } - (CALayer *)pulsingLayer:(CGRect)rect animation:(CABasicAnimation *)animation { CALayer *pulsingLayer = [CALayer layer]; pulsingLayer.borderWidth = 0.5 ; pulsingLayer.borderColor = [UIColor blackColor].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; } |
可以看看现在的效果是这样的
3. 加入背景色以及边框色的渐变效果，将单一的缩放动画合并为动画组CAAnimationGroup。
（ps: 除了改变背景色，还要设置并改变边框色的更主要原因是去除锯齿）
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 | // 设置一个初始化颜色的宏 #define ColorWithAlpha(r,g,b,a) [UIColor colorWithRed:r/ 255.0 green:g/ 255.0 blue:b/ 255.0 alpha:a] - ( void )drawRect:(CGRect)rect { CALayer *animationLayer = [CALayer layer]; // 这里同时创建[缩放动画、背景色渐变、边框色渐变]三个简单动画 NSArray *animationArray = [self animationArray]; // 将三个动画合并为一个动画组 CAAnimationGroup *animationGroup = [self animationGroupAnimations:animationArray]; //修改方法，将原先添加的动画由“简单动画”改为“动画组” CALayer *pulsingLayer = [self pulsingLayer:rect animation:animationGroup]; //将动画 Layer 添加到 animationLayer [animationLayer addSublayer:pulsingLayer]; [self.layer addSublayer:animationLayer]; } - (NSArray *)animationArray { NSArray *animationArray = nil; CABasicAnimation *scaleAnimation = [self scaleAnimation]; CAKeyframeAnimation *borderColorAnimation = [self borderColorAnimation]; CAKeyframeAnimation *backgroundColorAnimation = [self backgroundColorAnimation]; animationArray = @[scaleAnimation, backgroundColorAnimation, borderColorAnimation]; return animationArray; } - (CAAnimationGroup *)animationGroupAnimations:(NSArray *)array { CAAnimationGroup *animationGroup = [CAAnimationGroup animation]; animationGroup.beginTime = CACurrentMediaTime(); animationGroup.duration = 3 ; animationGroup.repeatCount = HUGE; animationGroup.animations = array; animationGroup.removedOnCompletion = NO; return animationGroup; } - (CABasicAnimation *)scaleAnimation { CABasicAnimation *scaleAnimation = [CABasicAnimation animationWithKeyPath:@ "transform.scale" ]; scaleAnimation.fromValue = @ 1 ; scaleAnimation.toValue = @(_multiple); return scaleAnimation; } // 使用关键帧动画，使得颜色动画不要那么的线性变化 - (CAKeyframeAnimation *)backgroundColorAnimation { CAKeyframeAnimation *backgroundColorAnimation = [CAKeyframeAnimation animation]; backgroundColorAnimation.keyPath = @ "backgroundColor" ; backgroundColorAnimation.values = @[(__bridge id)ColorWithAlpha( 255 , 216 , 87 , 0.5 ).CGColor, (__bridge id)ColorWithAlpha( 255 , 231 , 152 , 0.5 ).CGColor, (__bridge id)ColorWithAlpha( 255 , 241 , 197 , 0.5 ).CGColor, (__bridge id)ColorWithAlpha( 255 , 241 , 197 , 0 ).CGColor]; backgroundColorAnimation.keyTimes = @[@ 0.3 ,@ 0.6 ,@ 0.9 ,@ 1 ]; return backgroundColorAnimation; } - (CAKeyframeAnimation *)borderColorAnimation { CAKeyframeAnimation *borderColorAnimation = [CAKeyframeAnimation animation]; borderColorAnimation.keyPath = @ "borderColor" ; borderColorAnimation.values = @[(__bridge id)ColorWithAlpha( 255 , 216 , 87 , 0.5 ).CGColor, (__bridge id)ColorWithAlpha( 255 , 231 , 152 , 0.5 ).CGColor, (__bridge id)ColorWithAlpha( 255 , 241 , 197 , 0.5 ).CGColor, (__bridge id)ColorWithAlpha( 255 , 241 , 197 , 0 ).CGColor]; borderColorAnimation.keyTimes = @[@ 0.3 ,@ 0.6 ,@ 0.9 ,@ 1 ]; return borderColorAnimation; } - (CALayer *)pulsingLayer:(CGRect)rect animation:(CAAnimationGroup *)animationGroup { CALayer *pulsingLayer = [CALayer layer]; pulsingLayer.borderWidth = 0.5 ; pulsingLayer.borderColor = ColorWithAlpha( 255 , 216 , 87 , 0.5 ).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; } |
现在就有种渐变的感觉了
4. 同时创建三个扩散动画的CALyer，将开始动画的时间错开，同时添加到animationLayer上。
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | // 设置静态常量 pulsingCount ，表示 Layer 的数量 static NSInteger const pulsingCount = 3 ; // 设置静态常量 animationDuration ，表示动画时间 static double const animationDuration = 3 ; - ( void )drawRect:(CGRect)rect { CALayer *animationLayer = [CALayer layer]; // 利用 for 循环创建三个动画 Layer for ( int i = 0 ; i < pulsingCount; i++) { NSArray *animationArray = [self animationArray]; // 通过传入参数 i 计算，错开动画时间 CAAnimationGroup *animationGroup = [self animationGroupAnimations:animationArray index:i]; CALayer *pulsingLayer = [self pulsingLayer:rect animation:animationGroup]; [animationLayer addSublayer:pulsingLayer]; } [self.layer addSublayer:animationLayer]; } ... ... - (CAAnimationGroup *)animationGroupAnimations:(NSArray *)array index:( int )index { CAAnimationGroup *animationGroup = [CAAnimationGroup animation]; animationGroup.beginTime = CACurrentMediaTime() + (double)(index * animationDuration) / (double)pulsingCount; animationGroup.duration = animationDuration; animationGroup.repeatCount = HUGE; animationGroup.animations = array; animationGroup.removedOnCompletion = NO; return animationGroup; } ... ... |
然后效果有点……一言难尽……
真是很有纪律性的变化啊~~好吧，只需要加入动画曲线就好了
5. 最后加入动画速度曲线
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | ... ... - (CAAnimationGroup *)animationGroupAnimations:(NSArray *)array index:( int )index { CAAnimationGroup *animationGroup = [CAAnimationGroup animation]; animationGroup.beginTime = CACurrentMediaTime() + (double)(index * animationDuration) / (double)pulsingCount; animationGroup.duration = animationDuration; animationGroup.repeatCount = HUGE; animationGroup.animations = array; animationGroup.removedOnCompletion = NO; // 添加动画曲线。关于其他的动画曲线，也可以自行尝试 animationGroup.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionDefault]; return animationGroup; } ... ... |
如果需要点扩散，那就设置 frame 极小，同时扩散倍数增大即可。
将动画View垫在另一个圆形View之下即可实现最上方的效果。关闭背景色，重调边框色和边框宽度即可实现第二种效果。