相关疑难解决方法(0)

选择单元格后,我想处理更改单元格外观.我想委托方法collectionView:didSelectItemAtIndexPath:&collectionView:didDeselectItemAtIndexPath:是我应该编辑细胞.

-(void)collectionView:(UICollectionView *)collectionView 
       didSelectItemAtIndexPath:(NSIndexPath *)indexPath {

    DatasetCell *datasetCell = 
      (DatasetCell *)[collectionView cellForItemAtIndexPath:indexPath];

    [datasetCell replaceHeaderGradientWith:[UIColor skyBlueHeaderGradient]];
    datasetCell.backgroundColor = [UIColor skyBlueColor];
}

和

-(void)collectionView:(UICollectionView *)collectionView 
       didDeselectItemAtIndexPath:(NSIndexPath *)indexPath {

    DatasetCell *datasetCell = 
      (DatasetCell *)[collectionView cellForItemAtIndexPath:indexPath];

    [datasetCell replaceHeaderGradientWith:[UIColor grayGradient]];
    datasetCell.backgroundColor = [UIColor myDarkGrayColor];
}

这种方法很好,除非重用单元格.如果我在索引(0,0)处选择单元格,它会更改外观,但是当我向下滚动时,会有另一个单元格处于选定状态.

我相信我应该使用这种UICollectionViewCell方法-(void)prepareForReuse来准备细胞以便重复使用(即,将细胞外观设置为非选择状态),但它给我带来了困难.

-(void)prepareForReuse {
    if ( self.selected ) {
        [self replaceHeaderGradientWith:[UIColor skyBlueHeaderGradient]];
        self.backgroundColor = [UIColor skyBlueColor];
    } else {
        [self replaceHeaderGradientWith:[UIColor grayGradient]];
        self.backgroundColor = [UIColor myDarkGrayColor];
    }
}

当我向后滚动到顶部时,索引(0,0)处的单元格处于取消选择状态.

当我刚刚使用cell.backgroundView属性时,为了防止这种情况发生在:

-(void)prepareForReuse { …