CABasicAnimation *animation=[CABasicAnimation animationWithKeyPath:@"transform.scale"];
animation.toValue = @2.0f; //放大倍数
animation.duration = 0.5f;//动画时间
animation.autoreverses = NO;
//不还原初始状态
animation.removedOnCompletion = NO;
animation.fillMode = kCAFillModeForwards;
[self.button.layer addAnimation:animation forKey:@"scale"];
