春节后经过数天的努力上架了公司一个项目后，暂时又进入了空闲期，于是就着手整理一下项目中遇到的一些有意思的需求。废话不多说，先上效果图：
首先我们先创建一个工程，然后创建一个文件继承UIView,命名为Water。
在ViewController.h的viewDidLoad方法里面添加如下代码：
self.centerRadarView = [[Water alloc] initWithFrame:CGRectMake(0.25*[UIScreen mainScreen].bounds.size.width, 0.17*[UIScreen mainScreen].bounds.size.height, 0.48*[UIScreen mainScreen].bounds.size.width, 0.26*[UIScreen mainScreen].bounds.size.height)];
[self.view addSubview:_centerRadarView];
这里是为了在视图里面添加一个中心视图，在Water文件里创建的波纹动画可以以该视图为中心点做动画。然后我们可以在这个子视图上根据具体需求添加我们想要的东西，例如效果图里的倒计时。
然后在Water的.m文件里添加以下代码就行啦~
- (void) drawRect : (CGRect) rect {
[super drawRect:rect];
[[UIColor magentaColor] setFill];//中间部位的背景颜色
UIRectFill(rect);
NSInteger pulsingCount = 10;
double animationDuration = 8;
CALayer * animationLayer = [CALayer layer];
for (int i = 0; i < pulsingCount; i++) {
CALayer * pulsingLayer = [CALayer layer];
pulsingLayer.frame = CGRectMake(0, 0, rect.size.width, rect.size.height);
pulsingLayer.borderColor = [UIColor colorWithRed:0.96 green:0.65 blue:0.05 alpha:1].CGColor;
pulsingLayer.borderWidth = 18;
pulsingLayer.cornerRadius = rect.size.height / 2;
CAMediaTimingFunction * defaultCurve = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionDefault];
CAAnimationGroup * animationGroup = [CAAnimationGroup animation];
animationGroup.fillMode = kCAFillModeBackwards;
animationGroup.beginTime = CACurrentMediaTime() + (double)i * animationDuration / (double)pulsingCount;
animationGroup.duration = animationDuration;
animationGroup.repeatCount = HUGE;
animationGroup.timingFunction = defaultCurve;
CABasicAnimation * scaleAnimation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
scaleAnimation.fromValue = @1;
scaleAnimation.toValue = @3.2;
CAKeyframeAnimation * opacityAnimation = [CAKeyframeAnimation animationWithKeyPath:@"opacity"];
opacityAnimation.values= @[@0, @0.1, @0.2, @0.3, @0.4, @0.5, @0.6, @0.7, @0.8, @0.9, @1];
animationGroup.animations = @[scaleAnimation, opacityAnimation];
[pulsingLayer addAnimation:animationGroup forKey:@"plulsing"];
[animationLayer addSublayer:pulsingLayer];
}
[self.layer addSublayer:animationLayer];
}
到此就大功告成了！（此处应有“啪啪啪...”）
放上我的效果图（自我感觉和美工MM需求的差不多，逃~~~）：
谢谢阅读
好了，我要去“修仙”了~~哈哈
