设置单元格数据后如何更新 UICollectionView 中的单元格大小? [英] How to update size of cells in UICollectionView after cell data is set?

问题描述

所以我有一个 UICollectionView，每个单元格中都有不同大小的不同图像.当 cellForItemAtIndexPath: 被调用时，我使用一种方法更新 UICollectionViewCell，该方法在网络上异步获取图像并以全尺寸显示.

So I have a UICollectionView with a different image of different size in each cell. When cellForItemAtIndexPath: is called, I update the UICollectionViewCell with a method that fetches an image asynchronously on the web and displays it full size.

我的问题是我的单元格的大小已经预先设置了 sizeForItemAtIndexPath.我希望它被召回，以便单元格具有下载的图像大小.

My problem is the size of my cell is already set prior with sizeForItemAtIndexPath. I would like it to be recalled so the cell has the downloaded image size.

我该怎么做?

推荐答案

如果您已经设置了大小，请找到要刷新的单元格的索引:

If you have already set up your sizing, find the index of the cell you'd like to refresh:

NSIndexPath * indexPathOfCellToResize = // index path of cell to refresh
[myCollectionView reloadItemsAtIndexPaths:@[indexPathOfCellToResize]];

可能有更好的方法来做到这一点，但这里有一些有效的方法:

There's probably a better way to do this, but here's something that works:

在您的单元中创建委托协议

Create A Delegate Protocol In Your Cell

@protocol CellDelegate

- (void) imageIsReadyForCell:(id)cell;

@end

委托财产

@property (strong, nonatomic) id<CellDelegate>delegate;

在 Cell 中，当图像完成调用时:

In Cell, when image finished call:

[self.delegate imageIsReadyForCell:self];

然后在您的文件中托管接口中的 collectionView

Then in your file hosting the collectionView in interface

@interface SomeViewController : UIViewController <CellDelegate>

在.m

- (void) imageIsReadyForCell:(id)cell {
    NSIndexPath * indexOfReadyCell = [yourCollectionView indexPathForCell:cell];
    [myCollectionView reloadItemsAtIndexPaths:@[indexPathOfReadyCell]];
}

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