第一步：创建一个View，将这个View添加到当前的控制器

如：

CGFloat timeW = self.view.bounds.size.width;timeAnimation * timean = [[timeAnimation alloc]initWithFrame:CGRectMake(0,0,timeW,timeW)];    　timean.center = CGPointMake(self.view.bounds.size.width*0.5, self.view.bounds.size.height *0.5);[self.view addSubview:timean];

第二步：在View的.m文件中添加如下代码

#define PI 3.14159265358979323846

#define kradius self.bounds.size.width*0.1

-(instancetype)initWithFrame:(CGRect)frame{    if (self = [super initWithFrame:frame]) {        self.frame = frame;        self.backgroundColor = [UIColor clearColor];    }    return self;}- (void)drawRect:(CGRect)rect {    CGContextRef context = UIGraphicsGetCurrentContext();        [self greenRound:context];    self.alpha = 0.5;    [self test];}-(void)test{    // 2.创建缩放动画对象    CABasicAnimation *scale = [CABasicAnimation animation];    scale.keyPath = @"transform.scale";    scale.fromValue =[NSNumber numberWithFloat:0.0];    scale.toValue =[NSNumber numberWithFloat:1.0];    CABasicAnimation *scale1 = [CABasicAnimation animation];    scale1.keyPath = @"opacity";    scale1.fromValue =[NSNumber numberWithFloat:1.0];    scale1.toValue =[NSNumber numberWithFloat:0.0];    // 4.将所有的动画添加到动画组中    CAAnimationGroup *group = [CAAnimationGroup animation];    group.animations = @[scale,scale1];    group.duration =.6;    group.repeatCount = HUGE_VALF;    group.removedOnCompletion = NO;    group.fillMode = kCAFillModeForwards;    [self.layer addAnimation:group forKey:nil];}/**画绿色的圆*/-(void)greenRound:(CGContextRef)context{    CGContextSetRGBStrokeColor(context, 33/255.0, 177/255.0, 75/255.0, 1);//画笔线的颜色    CGContextSetLineWidth(context, 4.0);//线的宽度    // x,y为圆点坐标，radius半径，startAngle为开始的弧度，endAngle为 结束的弧度，clockwise 0为顺时针，1为逆时针。    CGContextAddArc(context, self.bounds.size.width *0.5,self.bounds.size.height*0.5,self.bounds.size.width*0.21, 0, 2*PI, 0); //添加一个圆    CGContextDrawPath(context, kCGPathStroke); //绘制路径}