CABasicAnimation问题

Question

所以，我在文档中读过，使用像

这样的块

beginAnimation
commitAnimation

不鼓励os4.0

。

所以我试图通过使用CABasicAnimation来使我的代码工作。我希望实现一个图像的帧从其缩略图大小（在我的视图中的某个位置）调整到全宽度位置，例如（0,120,320,240） - 在我的iPhone上。

到目前为止我所拥有的：

[CATransaction begin];
[CATransaction setValue:[NSNumber numberWithFloat:1.0] forKey:kCATransactionAnimationDuration]; 

CABasicAnimation *scalingAnimation;
scalingAnimation = [CABasicAnimation animationWithKeyPath:@"transform"];
scalingAnimation.duration=1.0/2;
scalingAnimation.autoreverses=YES;
scalingAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
scalingAnimation.fromValue=[NSValue valueWithCATransform3D:CATransform3DMakeScale(1.0, 1.0, 1.0)];
scalingAnimation.toValue=[NSValue valueWithCATransform3D:CATransform3DMakeScale(4, 4, 1)];

[b.layer addAnimation:scalingAnimation forKey:@"scaling"];

[CATransaction commit];

我的nextstep将首先尝试将图像移动到居中位置，然后将其缩放到正确的大小。但是，我怀疑我是否正确行事。任何人都可以评论我的代码/方法....有更好的方法吗？

Answer 1

我相信你现在已经解决了这个问题，但无论如何。

你不应该需要[CATransaction begin];和[CATransaction commit]; 我发现做这种事情的最简单方法是使用CAAnimationGroup并逐个添加动画。

一个例子是

CABasicAnimation *scaleX = [CABasicAnimation animationWithKeyPath:@"transform.scale.x"];
//this is not used, as the group provides the duration
scaleX.duration = duration;
scaleX.autoreverses = NO;

scaleX.toValue = [NSNumber numberWithFloat:1.0];
scaleX.fromValue = [NSNumber numberWithFloat:scaleFrom]; 
scaleX.fillMode = kCAFillModeForwards;
scaleX.removedOnCompletion = NO;

CABasicAnimation *scaleY = [CABasicAnimation animationWithKeyPath:@"transform.scale.y"];
//this is not used, as the group provides the duration
scaleY.duration = duration;
scaleY.autoreverses = NO;

scaleY.toValue = [NSNumber numberWithFloat:1.0];
scaleY.fromValue = [NSNumber numberWithFloat:scaleFrom]; 
scaleY.fillMode = kCAFillModeForwards;
scaleY.removedOnCompletion = NO;

//add in the translation animations

NSMutableArray* animationsArray = [NSMutableArray arrayWithObjects:scaleX,
                                                                   scaleY, 
//and any other animations you want in the group
                                       nil];

CAAnimationGroup *animationGroup = [CAAnimationGroup animation];
animationGroup.duration = 1.0/2;
animationGroup.timingFunction = [CAMediaTimingFunctionfunctionWithName:kCAMediaTimingFunctionEaseIn];
animationGroup.animations = animationsArray;
animationGroup.delegate = self;
animationGroup.removedOnCompletion = YES;
animationGroup.fillMode = kCAFillModeForwards;
[animationGroup setValue:@"imageTransform" forKey:@"AnimationName"];
[b.layer addAnimation:animationGroup forKey:@"imageTransform"];

虽然有一些陷阱。动画纯粹是视觉效果，因此在运行动画之前，请设置最终的视图框架。

您会注意到比例结束于1，这是为了确保您不会以缩放的图像层结束。相反，我们开始缩放并使其恢复正常。

翻译应该以同样的方式完成。

希望这有帮助

Answer 2

//in Event Method Copy Below code to place the image to the center

    CABasicAnimation* positionAnimation;
    positionAnimation = [CABasicAnimation animationWithKeyPath:@"position"];
    positionAnimation.fromValue = [NSValue valueWithCGPoint:imageView.layer.position];
    positionAnimation.toValue = [NSValue valueWithCGPoint:centerPointofView];
    positionAnimation.duration = 2.0;
    positionAnimation.fillMode = kCAFillModeForwards;
    positionAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn];
    positionAnimation.removedOnCompletion = NO;
    positionAnimation.delegate = self;
    [imageView.layer addAnimation:positionAnimation forKey:@"positionAnimation"];

// For Scale After image is in center copy below code

    - (void)animationDidStop:(CAAnimation *)theAnimation finished:(BOOL)flag{
    CAAnimation *animation = [imageView.layer animationForKey:@"positionAnimation"];
    if (animation == theAnimation) 
    {
        CABasicAnimation* scaleAnimation;
        scaleAnimation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
        scaleAnimation.fromValue = [NSNumber numberWithFloat:1];
        scaleAnimation.toValue = [NSNumber numberWithFloat:4.0];
        scaleAnimation.duration = 2.2;
        scaleAnimation.fillMode = kCAFillModeForwards;
       scaleAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn];
        scaleAnimation.removedOnCompletion = NO;
        scaleAnimation.delegate = self;
        [imageView.layer addAnimation:scaleAnimation forKey:@"scaleAnimation"];
    }
    else 
    {
        //if you want changes to image should remain forever 
        //place your code for scale & transform here
        ....................
        //now simple remove animation from layer
        [imageView.layer removeAllAnimations];
    }
}

Answer 3

不能使用

[UIView animateWithDuration:2.0
                        animations:^{ 
                            //animations
                        } 
                        completion:^(BOOL finished){
                           // completion methods
                        }];