iOS 購物車動畫

weixin_33727510發表於2017-02-25
iOS動畫

動畫效果：


610137-ac971dc56bad0ddf.gif
效果圖

Demo

一、計算動畫開始結束位置

方法：- (CGPoint)convertPoint:(CGPoint)point toView:(nullable UIView *)view;

1） 動畫開始位置fromCenter

CGPoint fromCenter =  [animationView convertPoint:CGPointMake(animationView.frame.size.width * 0.5f, animationView.frame.size.height * 0.5f) toView:keyWindow];

2）動畫結束位置endCenter

CGPoint endCenter = [endView convertPoint:CGPointMake(endView.frame.size.width * 0.5f, endView.frame.size.height * 0.5f) toView:keyWindow];

二、計算貝塞爾曲線（拋物線）的兩個控制點

610137-4aabdd001af0bc6d.png
圖1
  • controlPoint1是控制點1
  • controlPoint2是控制點2
  • A是controlPoint1和controlPoint2的中點
  • controlPointC是fromCenter和B的中點

1）先設定控制點距最高點（fromCenter或endCenter）的水平距離controlPointEY，本篇預設controlPointEY = 100，即圖1中點controlPointC到點A的距離。

2）計算控制點相對於點A的距離controlPointEX，即controlPoint1到A距離或controlPoint2到A距離，本篇設定為fromCenter.x到endCenter.x的1/4，即controlPointEX = (endCenter.x - fromCenter.x) * 0.25f;

3）計算兩個控制點

CGPoint controlPoint1 = CGPointMake(controlPointCX - controlPointEX, controlPointCY - controlPointEY);
CGPoint controlPoint2 = CGPointMake(controlPointCX + controlPointEX, controlPointCY - controlPointEY);

三、複製動畫的layer

NSString *str = ((UIButton *)animationView).titleLabel.text;
_animationLayer = [CATextLayer layer];
_animationLayer.bounds = animationView.bounds;
_animationLayer.position = fromCenter;
_animationLayer.alignmentMode = kCAAlignmentCenter;//文字對齊方式
_animationLayer.wrapped = YES;
_animationLayer.contentsScale = [UIScreen mainScreen].scale;
_animationLayer.string = str;
_animationLayer.backgroundColor = [UIColor redColor].CGColor;
[keyWindow.layer addSublayer:_animationLayer];

四、動畫組合

1）運動軌跡（拋物線）

UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:fromCenter];
[path addCurveToPoint:endCenter controlPoint1:controlPoint1 controlPoint2:controlPoint2];
CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
pathAnimation.path = path.CGPath;

2）旋轉起來

CABasicAnimation *rotateAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];
rotateAnimation.removedOnCompletion = YES;
rotateAnimation.fromValue = [NSNumber numberWithFloat:0];
rotateAnimation.toValue = [NSNumber numberWithFloat:10 * M_PI];
rotateAnimation.timingFunction=[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn]

3）縮放動畫

CABasicAnimation *scaleAnimation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
scaleAnimation.removedOnCompletion = NO;
scaleAnimation.fromValue = [NSNumber numberWithFloat:1.0];
scaleAnimation.toValue = [NSNumber numberWithFloat:0.2];

4）透明度動畫

CABasicAnimation *alphaAnimation = [CABasicAnimation animationWithKeyPath:@"opacity"];
alphaAnimation.removedOnCompletion = NO;
alphaAnimation.fromValue = [NSNumber numberWithFloat:1.0];
alphaAnimation.toValue = [NSNumber numberWithFloat:0.1];

5）動畫組合

CAAnimationGroup *groups = [CAAnimationGroup animation];
groups.animations = @[pathAnimation,rotateAnimation, scaleAnimation, alphaAnimation];
groups.duration = kShoppingCartDuration;
groups.removedOnCompletion=NO;
groups.fillMode=kCAFillModeForwards;
groups.delegate = self;
[_animationLayer addAnimation:groups forKey:@"group"];

五、其他

模擬貝塞爾曲線

參考：iOS 一分鐘搞定加入購物車的互動動畫

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