按钮出现的时候有动画效果

代码：

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    UIButton *button=[UIButton buttonWithType:UIButtonTypeRoundedRect];
    button.frame=CGRectMake(10, 100, 100, 200);
    button.backgroundColor=[UIColor redColor];
    [button setTitle:@"按钮" forState:UIControlStateNormal];
    [self.view addSubview:button];

    //按钮的动画效果
    [self buttonAnimation:button];

}

//按钮出现的时候有一个动画效果
- (void)buttonAnimation:(UIButton *)sender
{
    CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"transform"];

    CATransform3D scale1 = CATransform3DMakeScale(0.5, 0.5, 1);
    CATransform3D scale2 = CATransform3DMakeScale(1.2, 1.2, 1);
    CATransform3D scale3 = CATransform3DMakeScale(0.9, 0.9, 1);
    CATransform3D scale4 = CATransform3DMakeScale(1.0, 1.0, 1);

    NSArray *frameValues = [NSArray arrayWithObjects:
                            [NSValue valueWithCATransform3D:scale1],
                            [NSValue valueWithCATransform3D:scale2],
                            [NSValue valueWithCATransform3D:scale3],
                            [NSValue valueWithCATransform3D:scale4],
                            nil];

    [animation setValues:frameValues];

    NSArray *frameTimes = [NSArray arrayWithObjects:
                           [NSNumber numberWithFloat:0.0],
                           [NSNumber numberWithFloat:0.5],
                           [NSNumber numberWithFloat:0.9],
                           [NSNumber numberWithFloat:1.0],
                           nil];
    [animation setKeyTimes:frameTimes];

    animation.fillMode = kCAFillModeForwards;
    animation.duration = 0.3f;

    [sender.layer addAnimation:animation forKey:@"DSPopUpAnimation"];
}