UICollectionView - 图像是随机设置的

我在我的应用程序中使用collectionView。我正在 didSelect 委托中为单元格背景视图设置图像。但是当我选择一个单元格索引路径时，图像将设置为 3 个单元格索引路径。当我滚动 collectionView 时，图像会随机更改？请帮我。提前致谢。

- (void)viewDidLoad
{
    [super viewDidLoad];

    [collection registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:uio];
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:       (NSInteger)section
{
     return 50;
}

 - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{

    UICollectionViewCell *cell = [collection dequeueReusableCellWithReuseIdentifier:uio
 forIndexPath:indexPath];
    cell.backgroundColor = [UIColor whiteColor];
   return cell;
}

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
 {
    NSLog(@"index %@",indexPath);
    UICollectionViewCell *cell = [collection cellForItemAtIndexPath:indexPath];

    cell.backgroundView =[[UIImageView alloc]initWithImage:[UIImage imageNamed:@"download.jpg"]];

 }

那是因为你重复使用了你的细胞。一种选择是使用一个字典变量来表示您的单元格已被选择，如果尚未选择，则重置图像。

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
    NSLog(@"index %@",indexPath);
    UICollectionViewCell *cell = [collection cellForItemAtIndexPath:indexPath];

    cell.backgroundView =[[UIImageView alloc]initWithImage:[UIImage imageNamed:@"download.jpg"]];

    [selectedDictionary setObject:[NSNumber numberWithBool:YES] forKey:[NSNumber numberWithInteger:indexPath.row]];
}

然后在您的 cellForItemAtIndexPath 方法中您将检查该值

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{

    UICollectionViewCell *cell = [collection dequeueReusableCellWithReuseIdentifier:uio
 forIndexPath:indexPath];
    BOOL selected = [[selectedDictionary objectForKey:[NSNumber numberWithInteger:indexPath.row]] boolValue];

    if(selected){
        cell.backgroundView =[[UIImageView alloc]initWithImage:[UIImage imageNamed:@"download.jpg"]];
    }else{
        cell.backgroundView = nil;
    }

    cell.backgroundColor = [UIColor whiteColor];
   return cell;
}

当然，如果您使用某种对象作为模型，那么在这里有一个选定的变量是合适的，您将不再需要 nsdictionary 。