首先看下效果展示：
动画.gif
Core Animation(核心动画)是一组功能强大、效果华丽的动画API，无论在iOS系统或者在你开发的App中，都有大量应用。
楼主简单的利用UIBezierPath绘画圆，然后利用CABasicAnimation的opacity调整视图的透明度，然后利用CABasicAnimation的transform.scale来实现圆的放大缩小，如果想要了解更多传送门：
http://www.imlifengfeng.com/blog/?p=548
废话不多所上代码
基本都是通过懒加载实现
创建CAShapeLayer
- (CAShapeLayer *)shapeLayer{
if (_shapeLayer==nil) {
_shapeLayer = [CAShapeLayer layer];
_shapeLayer.frame = CGRectMake(100, 100, 100, 100);
_shapeLayer.fillColor = [UIColor blueColor].CGColor;
_shapeLayer.strokeColor = [UIColor blackColor].CGColor;
//通过贝塞尔曲线绘制圆
CGFloat startAngle = 0.0;
CGFloat endAngle = M_PI *2;
UIBezierPath *bezierPath = [UIBezierPath bezierPathWithArcCenter:CGPointMake(50, 50) radius:50 startAngle:startAngle endAngle:endAngle clockwise:YES];
_shapeLayer.path = bezierPath.CGPath;
}
return _shapeLayer;
}
添加动画组这里用到CAAnimationGroup
- (CAAnimationGroup *)animaGroup{
if (_animaGroup == nil) {
CABasicAnimation * _opacityAnima = [CABasicAnimation animationWithKeyPath:@"opacity"];
_opacityAnima.fromValue = @(0.7);
_opacityAnima.toValue = @(0.3);
CABasicAnimation *expandAnimation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
expandAnimation.fromValue = [NSNumber numberWithFloat:1]; // 开始时的倍率
expandAnimation.toValue = [NSNumber numberWithFloat:1.5]; // 结束时的倍率
_animaGroup = [CAAnimationGroup animation];
_animaGroup.animations = @[ expandAnimation,_opacityAnima];
_animaGroup.duration = 3;
_animaGroup.repeatCount = HUGE;
_animaGroup.autoreverses = YES;
}
return _animaGroup;
}
具体里面的属性可以点击上文链接了解不多解释，只实现
动画开始、停止方法
/Start Animation
- (void)startAnimation{
[self.layer addSublayer:self.shapeLayer];
[self.shapeLayer addAnimation:self.animaGroup forKey:@"scaleGroup"];
}
//Stop Animation
- (void)stopAnimation{
if (_shapeLayer) {
[self.shapeLayer removeAllAnimations];
[self.shapeLayer removeFromSuperlayer];
}
}
代码地址：https://github.com/lanjiaoli/Animation
有不足的地方大家多多指出，谢谢
