經常寫動畫，好的動畫效果，可以使應用的level提升好幾個檔次，

下面有一個動畫顯得很舒服!個人表示很喜歡，在此做個記錄。

//貝塞爾曲線動畫
- (IBAction)clickAction:(UIButton *)sender {
    //把圖片加到view上
    UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(40, 310, 20, 20)];
    imageView.image = [UIImage imageNamed:@"cm_center_discount"];
    [self
 
.view addSubview:imageView];

    CALayer *layer = [[CALayer alloc] init];
    layer.contents = imageView.layer.contents;
    layer.frame = imageView.frame;
    layer.opacity = 1;
    [self.view.layer addSublayer:layer];

    //都以self.view為參考系
    UIBezierPath *path = [UIBezierPath bezierPath];

    //動畫起點
 

    CGPoint startPoint = CGPointMake(50, 320);
    [path moveToPoint:startPoint];

    //動畫終點
    CGPoint endpoint = CGPointMake(320, 568);

    //貝塞爾曲線中間點
    float sx = startPoint.x;
    float sy = startPoint.y;
    float ex = endpoint.x;
    float ey = endpoint.y;
    float x = sx+(ex-sx)/3;
    float y = sy+(ey-sy)*0.5
 
-400;
    CGPoint centerPoint = CGPointMake(x,y);
    [path addQuadCurveToPoint:endpoint controlPoint:centerPoint];

    CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
    animation.path = path.CGPath;
    animation.fillMode = kCAFillModeForwards;
    animation.duration = 0.7;
    animation.delegate = self;
    animation.autoreverses = YES;//是否自動退回
    animation.removedOnCompletion = NO;//完成後是否移除
    animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn];
    [layer addAnimation:animation forKey:@"buy"];
}