使用 CAKeyframeAnimation 移动图层 - 图层回到第一个位置

Question

首先，我使用该代码将我的图层从一个点移动到另一个点：

        CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:@"position"];
        anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
        anim.fromValue = [NSValue valueWithCGPoint:startPt];
        anim.toValue = [NSValue valueWithCGPoint:endPt];
        anim.repeatCount = 0;
        anim.duration = 1.0;
       [self.firstBall.ballLayer addAnimation:anim forKey:@"position"];

这在动画清除第一层并在其他地方重绘之后。

    NSInteger firstBallIndex = [self.fieldsArray indexOfObject:self.firstBall];
           NSInteger secondBallIndex = [self.fieldsArray indexOfObject:self.secondBall];
           Field* ballFrom = [self.fieldsArray objectAtIndex:firstBallIndex];
           Field* ballTo = [self.fieldsArray objectAtIndex:secondBallIndex];
           ballTo.ballLayer = ballFrom.ballLayer;
           CGPoint startPt = CGPointMake(self.firstBall.ballCoordinates.x,self.firstBall.ballCoordinates.y);
    CGPoint endPt = CGPointMake(self.secondBall.ballCoordinates.x,self.secondBall.ballCoordinates.y);
    ballTo.ballLayer.frame = CGRectMake(endPt.x, endPt.y, self.ballSize, self.ballSize);
             ballFrom.ballLayer = nil;
             [self.fieldsArray replaceObjectAtIndex:firstBallIndex withObject:ballFrom];
             [self.fieldsArray replaceObjectAtIndex:secondBallIndex withObject:ballTo];

但接下来我尝试为我的图层设置动画以移动几次。所以我使用那个代码：

    CGMutablePathRef path = CGPathCreateMutable();
    NSMutableArray * pathArray = [algorithm CreatePath];
  CGPathMoveToPoint(path, NULL, self.firstBall.ballCoordinates.x, self.firstBall.ballCoordinates.y);
        for (NSValue * pointValue in pathArray) {
            CGPoint point = [pointValue CGPointValue];
            Field* field = [self FindFieldWithPoint:point];
            CGPathAddLineToPoint(path, NULL, field.ballCoordinates.x, field.ballCoordinates.y);
        }
 CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
pathAnimation.duration = 2.0;
pathAnimation.path = path;
[UIView animateWithDuration:5
                      delay:5
                    options:UIViewAnimationOptionAllowUserInteraction
                 animations:^{
                     [self.firstBall.ballLayer addAnimation:pathAnimation forKey:@"position"];
                 }
                 completion:^ (BOOL finished)
 {
     if (finished) {


         ballTo.ballLayer.frame = CGRectMake(endPt.x, endPt.y, self.ballSize, self.ballSize);
         ballFrom.ballLayer = nil;
         [self.fieldsArray replaceObjectAtIndex:firstBallIndex withObject:ballFrom];
         [self.fieldsArray replaceObjectAtIndex:secondBallIndex withObject:ballTo];
     }
 }];

现在：

1. 当我在“完成”中注释代码时： 我的图层动画正常，从一个点移动到另一个点，但最后它回到第一个坐标

2. 当我取消注释“完成”中的代码时： 我的图层从第一个坐标移动到最后一个坐标，就像它不知道之间的位置：/

Answer 1

这是错误的：

[UIView animateWithDuration:5 // and so on

不要尝试以这种方式将图层动画与视图动画结合起来。只需将动画添加到图层并退后即可。 :)

CAKeyframeAnimation *pathAnimation = 
    [CAKeyframeAnimation animationWithKeyPath:@"position"];
pathAnimation.duration = 2.0;
pathAnimation.path = path;
[self.firstBall.ballLayer addAnimation:pathAnimation forKey:@"position"];

并立即设置你的最终位置，以防止以后跳回：

ballTo.ballLayer.frame = 
    CGRectMake(endPt.x, endPt.y, self.ballSize, self.ballSize);

如果您仍需要了解动画何时结束，请在您的 pathAnimation 上设置一个委托。