什么是动画UICollectionViewCell时bounds.size和frame.size之间的相关性 [英] What is the correlation between bounds.size and frame.size when animating UICollectionViewCell

问题描述

我读过的几个职位（如 http://stackoverflow.com/a/5340339/1084822 并 http://stackoverflow.com/a/15582466/1084822 ），要调整动画一个UIView，我们不能动画框架，我们必须bounds.size，bounds.origin和位置的混合做。

I've read on several posts (like http://stackoverflow.com/a/5340339/1084822 and http://stackoverflow.com/a/15582466/1084822) that to resize a UIView with animation, we can't animate the frame and we must do it with a mix of bounds.size, bounds.origin and position.

不过，我找不到什么这些属性和那些帧之间的相关性。

However, I can't find what is the correlation between those properties and those of the frame.

我有一个自定义布局的UICollectionView。当细胞被删除，布局被刷新，每一个细胞通过 prepareLayout 和 layoutAttributesForElementsInRect获得其新的框架：方法。然后， finalizeCollectionViewUpdates 方法（在这里我们可以编辑动画）被调用，最后细胞，并开​​始调整。

I have a UICollectionView with a custom layout. When a cell is deleted, the layout is refreshed and every cell gets its new frame through the prepareLayout and layoutAttributesForElementsInRect: methods. Then, the finalizeCollectionViewUpdates method (where we can edit animations) gets called and finally the cells move and get resized.

我已经通过试错与细胞动画做了很多的探索，这里是我发现了什么：

I've done a lot of exploration by trial and error with the cells animation and here is what I found :

• 3动画默认设置为我这是位置，bounds.origin和bounds.size
可见单元格

• 当我改变了从/到这些动画的值，只有单元格的位置受到影响，从来没有它的大小

当我坚持到动画的默认值，并检查它们的值与这些日志，

When I stick to the default values of the animations and check their values with these logs,

- (void)finalizeCollectionViewUpdates {
    for(UICollectionViewCell* cell in [self.collectionView visibleCells]) {
        NSLog(@"cell: %@", cell);
        for(NSString* key in cell.layer.animationKeys) {
            CABasicAnimation* animation = (CABasicAnimation*)[cell.layer animationForKey:key];
            NSLog(@"animation %@: from %@ to %@", key, animation.fromValue, animation.toValue);
        }
    }
}

我得到这个为在缩小细胞（其框架重新present最终状态）：

I get this for the shrinking cell (its frame represent its final state):

cell: <PlayQueueSongCell: 0x7fbf1bc8ebe0; baseClass = UICollectionViewCell; frame = (53.3333 80; 480 480); opaque = NO; animations = { position=<CABasicAnimation: 0x7fbf1bf54e20>; bounds.origin=<CABasicAnimation: 0x7fbf1bf556b0>; bounds.size=<CABasicAnimation: 0x7fbf1bf557a0>; }; layer = <CALayer: 0x7fbf1bc8e9f0>>
animation position: from NSPoint: {666.66666666666674, 0} to NSPoint: {0, 0}
animation bounds.origin: from NSPoint: {0, 0} to NSPoint: {0, 0}
animation bounds.size: from NSSize: {160, 160} to NSSize: {0, 0}

和本作的花费细胞（其框架重新present最终状态）：

and this for the expending cell (its frame represent its final state):

cell: <PlayQueueSongCell: 0x7fbf1bd6cd00; baseClass = UICollectionViewCell; frame = (640 0; 640 640); opaque = NO; animations = { position=<CABasicAnimation: 0x7fbf1bf55b70>; bounds.origin=<CABasicAnimation: 0x7fbf1bf55e20>; bounds.size=<CABasicAnimation: 0x7fbf1bf55f10>; }; layer = <CALayer: 0x7fbf1bd73200>>
animation position: from NSPoint: {666.66666666666652, 0} to NSPoint: {0, 0}
animation bounds.origin: from NSPoint: {0, 0} to NSPoint: {0, 0}
animation bounds.size: from NSSize: {-160, -160} to NSSize: {0, 0}

中看到结果慢动作：

当我删除bounds.size动画与code的此块，

When I remove the bounds.size animation with this block of code,

- (void)finalizeCollectionViewUpdates {
    for(UICollectionViewCell* cell in [self.collectionView visibleCells]) {
        for(NSString* key in cell.layer.animationKeys) {
            [cell.layer removeAnimationForKey:@"bounds.size"];
        }
    }
}

我可以看到，只有单元格的位置会受到影响......

而当我改变bounds.size的值（0,0） - 与code此块>（1000,1000）：

And when I change the values of bounds.size to (0,0) -> (1000,1000) with this block of code:

- (void)finalizeCollectionViewUpdates {
    for(UICollectionViewCell* cell in [self.collectionView visibleCells]) {
        for(NSString* key in cell.layer.animationKeys) {
            [cell.layer removeAnimationForKey:@"bounds.size"];
            CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"bounds.size"];
            [animation setFromValue:[NSValue valueWithCGSize:CGSizeZero]];
            [animation setToValue:[NSValue valueWithCGSize:CGSizeMake(1000, 1000)]];
            [animation setDuration:0.3];
            [cell.layer addAnimation:animation forKey:@"bounds.size"];
        }
    }
}

我仍然可以看到，只有单元格的位置会受到影响......

由于细胞中获取新的帧就在动画开始前和bounds.size不影响细胞的大小，我无法找到一个方法来平滑地改变它的大小。

Since the cell gets its new frame just before the animation starts and the bounds.size does not affect the cell's size, I can't find a way to change its size smoothly.

什么是bounds.size和frame.size之间的关系，每个人都在谈论和一个如何动画单元格的大小？

What is the correlation between the bounds.size and the frame.size that everyone is talking about and how can one animate the size of the cell?

推荐答案

我发现是因为它把细胞以意外方式先删除bounds.size动画解决方案。然后，我创建与将要模拟其previous大小和值1停止值启动transform.scale动画。

The solution I found is to first remove the bounds.size animation since it moves the cell in an unwanted way. Then, I create a transform.scale animation that starts with a value that will simulate its previous size and stops with a value of 1.

if([cell.layer animationForKey:@"bounds.size"]) {
    [cell.layer removeAnimationForKey:@"bounds.size"];

    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"transform.scale"];
    animation.duration = 0.3;
    if(CGSizeEqualToSize(cell.frame.size, self.itemSize)) { //shrinking cell
        animation.fromValue = @1.333;
        animation.toValue = @1;
    } else {                                                //expending cell
        animation.fromValue = @0.75;
        animation.toValue = @1;
    }
    [cell.layer addAnimation:animation forKey:@"transform.scale"];
}

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