为何 cell 无法高亮和选中？

- (BOOL )collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath {

    return YES;
}

- (void )collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
    UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
    cell.selectedBackgroundView.backgroundColor = [UIColor purpleColor];
}

这样点选以后颜色没有变化

indexpath

collectionview

cell

colo

5 条回复 • 2015-09-12 16:18:59 +08:00

PopeyeLau

2015-09-11 17:08:03 +08:00

应该是在 cellForItemAtIndexPath 方法设置 cell 的 selectedBackgroundView 跟 backgroundColor 吧.
如果前面没设置, didSelectItemAtIndexPath 里面取 selectedBackgroundView 应该是 nil.

l12ab

2015-09-11 22:13:26 +08:00

我怎么记得默认带选中效果？

kobe1941

2015-09-11 22:55:54 +08:00

一般子类化 cell ，然后自行设置高亮和选中的效果

strom001

2015-09-12 15:23:03 +08:00

```objc
- (void )collectionView:(UICollectionView *)colView didHighlightItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell* cell = [colView cellForItemAtIndexPath:indexPath];
cell.contentView.backgroundColor = [UIColor blueColor];
}

- (void )collectionView:(UICollectionView *)colView didUnhighlightItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell* cell = [colView cellForItemAtIndexPath:indexPath];
cell.contentView.backgroundColor = nil;
}
```
这段是 xcode 文档里的

strom001

2015-09-12 16:18:59 +08:00

@PopeyeLau selectedBackgroundView 在 cellForItem 那里设置了也是 nil 啊……另外我在 IB 里设置了 cell 颜色，后来改为默认，结果代码设置颜色就不管用了……