UIAlertView动画模拟

CAKeyframeAnimation * animation; 
    animation = [CAKeyframeAnimation animationWithKeyPath:@"transform"]; 
    animation.duration = 0.5; 
    animation.delegate = self;
    animation.removedOnCompletion = YES;
    animation.fillMode = kCAFillModeForwards;
    
    NSMutableArray *values = [NSMutableArray array];
    [values addObject:[NSValue valueWithCATransform3D:CATransform3DMakeScale(0.1, 0.1, 1.0)]];
    [values addObject:[NSValue valueWithCATransform3D:CATransform3DMakeScale(1.2, 1.2, 1.0)]]; 
    [values addObject:[NSValue valueWithCATransform3D:CATransform3DMakeScale(0.9, 0.9, 0.9)]]; 
    [values addObject:[NSValue valueWithCATransform3D:CATransform3DMakeScale(1.0, 1.0, 1.0)]]; 
    
    animation.values = values;
    animation.timingFunction = kCAMediaTimingFunctionEaseIn;;
    [self.layer addAnimation:animation forKey:nil];