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标题: ios - 如何在 CollectionView 中选择单个单元格并取消选择所有其他单元格 [打印本页]

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作者: 菜鸟教程小白    时间: 2022-12-13 00:03
标题: ios - 如何在 CollectionView 中选择单个单元格并取消选择所有其他单元格

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I have horizontal CollectionView in which selected cell have orange gradient color and all other deselected cells gray color i m using only didselect delegate method but i am getting problem of multiple cells selected and i have problem with same concept in table view while scrolling and i have searched a lot but i have not get proper answer of cell reusability

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- (UICollectionViewCell *)collectionViewUICollectionView *)collectionView cellForItemAtIndexPathNSIndexPath *)indexPath
{


    DateTimeCell * cell = [self.collectionView dequeueReusableCellWithReuseIdentifier"DateTimeCellID" forIndexPath:indexPath];



    if (self.selectedIndexPath != nil && indexPath == self.selectedIndexPath)
    {

        CAGradientLayer *gradient = [CAGradientLayer layer];
        gradient.frame = cell.mainView.bounds;
        gradient.startPoint = CGPointZero;

        gradient.endPoint = CGPointMake(1, 1);
        gradient.colors = [NSArray arrayWithObjectsid)[[UIColor colorWithRed:238.0/255.0 green:42.0/255.0 blue:123/255.0 alpha:1.0] CGColor],(id)[[UIColor colorWithRed:241.0/255.0 green:90.0/255.0 blue:41.0/255.0 alpha:1.0] CGColor], nil];
        [gradient setMasksToBounds:NO];
        cell.mainView.backgroundColor = [UIColor clearColor];
        [cell.mainView.layer insertSublayer:gradient atIndex:0];

        [indexPaths addObject:self.selectedIndexPath];

    }
     else
     {
         [cell.mainView setBackgroundColor:[self colorWithHexString"383F4A"]];
      }

    return cell;
}

-(void)collectionViewUICollectionView *)collectionView didSelectItemAtIndexPathNSIndexPath *)indexPath
{


    indexPaths = [NSMutableArray arrayWithObjects:indexPath, nil];

    if (self.selectedIndexPath)
    {
        // if we had a previously selected cell

        if ([indexPath compare:self.selectedIndexPath] == NSOrderedSame)
        {
            // if it's the same as the one we just tapped on, then we're unselecting it

            NSLog(@"Selected");

        }
        else
        {
            // if it's different, then add that old one to our list of cells to reload, and
            // save the currently selected indexPath

            [indexPaths addObject:self.selectedIndexPath];
            self.selectedIndexPath = indexPath;
        }
    }
    else
    {
        // else, we didn't have previously selected cell, so we only need to save this indexPath for future reference

        self.selectedIndexPath = indexPath;

    }



    dispatch_async(dispatch_get_main_queue(), ^{
         [collectionView reloadItemsAtIndexPaths:indexPaths];
    });


}

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Best Answer-推荐答案

像下面这样全局获取一个全局 selectedIndexPath

NSIndexPath *selectedIndexPath = [[NSIndexPath alloc] indexPathForRow:0 inSection:0];

在委托(delegate)方法中编写下面的代码

- (UICollectionViewCell *)collectionViewUICollectionView *)collectionView cellForItemAtIndexPathNSIndexPath *)indexPath
{


DateTimeCell * cell = [self.collectionView dequeueReusableCellWithReuseIdentifier"DateTimeCellID" forIndexPath:indexPath];

if self.selectedIndexPath == indexPath
{
  // do what you want to do with your selected cell
}
else
{
    // do what you want to do with your deselected cell
}


return cell;
}

 -(void)collectionViewUICollectionView *)collectionView didSelectItemAtIndexPathNSIndexPath *)indexPath
{

self.selectedIndexPath = indexPath
[self.collectionView reloadData];


 }

关于ios - 如何在 CollectionView 中选择单个单元格并取消选择所有其他单元格，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/42592767/

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