方法一：在控制器里面進行修改：

代理方法：
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    
    DiscoverRechangeCenterCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"DiscoverRechangeCenterCell" forIndexPath:indexPath];
    
    cell.discoverRechangeCenterModel = self.sourceArr[indexPath.row];
    
    
    //默認選中效果
    if (indexPath == self.selectIndexPath) {

        cell.backgroundImgV.hidden = NO;

    } else {

        cell.backgroundImgV.hidden = YES;
    }
    
    return cell;
}
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
    
    DiscoverRechangeCenterCell *cell = (DiscoverRechangeCenterCell *)[collectionView cellForItemAtIndexPath:indexPath];
    
    //選中之后的cell變顏色
    [self updateCellStatus:cell selected:NO];
    
    self.selectIndexPath = indexPath;
    [collectionView reloadData];
    
}

//取消選中操作
- (void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath
{
    DiscoverRechangeCenterCell *cell = (DiscoverRechangeCenterCell *)[collectionView cellForItemAtIndexPath:indexPath];
    [self updateCellStatus:cell selected:YES];
}
// 改變cell的背景圖片
-(void)updateCellStatus:(DiscoverRechangeCenterCell *)cell selected:(BOOL)selected{
    
    cell.backgroundImgV.hidden = selected;
    
}

方法二：在UICollectionViewCell中重寫select方法實現

UICollectionViewCell中:
- (void)setSelected:(BOOL)selected {
    
    [super setSelected:selected];
    
    if (selected) {
        
        self.backgroundImgV.hidden = NO;
        
    } else {
        
        self.backgroundImgV.hidden = YES;
        
    }
    
}
控制器中：
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    
    DiscoverRechangeCenterCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"DiscoverRechangeCenterCell" forIndexPath:indexPath];
    
    cell.discoverRechangeCenterModel = self.sourceArr[indexPath.row];
    
    
    //默認選中效果
    if (indexPath == self.selectIndexPath) {

        cell.backgroundImgV.hidden = NO;

    } else {

        cell.backgroundImgV.hidden = YES;
    }
    
    return cell;
}

-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
    
    DiscoverRechangeCenterCell *cell = (DiscoverRechangeCenterCell *)[collectionView cellForItemAtIndexPath:indexPath];

    self.selectIndexPath = indexPath;

    [cell setSelected:YES];
    [collectionView reloadData];
    
}