如何获得 UICollectionViewCell 的正确信息？

怎么样

-(CGRect)rectForCellatIndexPath:(NSIndexPath *)indexPath {


UICollectionViewCell *cell = [self cellForItemAtIndexPath:indexPath];


if (!cell) {
return CGRectZero;
}


return cell.frame;


}

作为 UICollectionView的一个分类？

#import <UIKit/UIKit.h>


@interface UICollectionView (CellFrame)


-(CGRect)rectForCellatIndexPath:(NSIndexPath *)indexPath;


@end




#import "UICollectionView+CellFrame.h"


@implementation UICollectionView (CellFrame)


-(CGRect)rectForCellatIndexPath:(NSIndexPath *)indexPath {


UICollectionViewCell *cell = [self cellForItemAtIndexPath:indexPath];


if (!cell) {
return CGRectZero;
}


return cell.frame;


}


@end

我发现最好的方法是这样做:

目标 C

UICollectionViewLayoutAttributes *attributes = [self.collectionView layoutAttributesForItemAtIndexPath:indexPath];

斯威夫特

let attributes = collectionView.layoutAttributesForItem(at: indexPath)

然后您可以通过 attributes.frame或 attributes.center访问该位置

你可以迅速地做:

//for any cell in collectionView
let rect = self.collectionViewLayout.layoutAttributesForItemAtIndexPath(clIndexPath).frame


//if you only need for visible cells
let rect = cellForItemAtIndexPath(indexPath)?.frame

只需要两行代码就可以得到完美的帧:

目标-C

UICollectionViewLayoutAttributes * theAttributes = [collectionView layoutAttributesForItemAtIndexPath:indexPath];


CGRect cellFrameInSuperview = [collectionView convertRect:theAttributes.frame toView:[collectionView superview]];

let theAttributes = collectionView.layoutAttributesForItem(at: indexPath)
let cellFrameInSuperview = collectionView.convert(theAttributes.frame, to: collectionView.superview)