如何以编程方式修复带有UIImageView Overlap的UICollectionViewCell

Question

我将以编程方式创建UICollectionView到uiview（我使用单个视图）。 像这样

UICollectionViewFlowLayout *CATLayout=[[UICollectionViewFlowLayout alloc]init];
CATLayout.minimumInteritemSpacing = 2.0f;
CATLayout.minimumLineSpacing = 2.0f;
CATLayout.scrollDirection = UICollectionViewScrollDirectionVertical;
CATLayout.sectionInset = UIEdgeInsetsMake(1.0f, 1.0f, 1.0f, 1.0f);

self.ColStickersListView=[[UICollectionView alloc]initWithFrame:CGRectMake(0, 0, StickersListView.frame.size.width, StickersListView.frame.size.height) collectionViewLayout:CATLayout];
self.ColStickersListView.delegate=self;
self.ColStickersListView.dataSource=self;
self.ColStickersListView.tag=2;
[self.ColStickersListView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"CollStickersList"];
[self.ColStickersListView setBackgroundColor:[UIColor clearColor]];
[StickersListView addSubview:ColStickersListView];

和

UICollectionViewCell *cell = [ColStickersListView dequeueReusableCellWithReuseIdentifier:@"CollStickersList" forIndexPath:indexPath];



    // for background selected
    NSString *imageName=anObject;
    NSString *filename=[NSString stringWithFormat:@"%@/Stickers/List/%@",[appDel DocsPath],imageName];

    NSLog(@"%@",filename);


    cell.backgroundColor=[UIColor clearColor];
    UIImage *image=[UIImage imageNamed:filename];



    UIImageView *photoView=[[UIImageView alloc]initWithFrame:CGRectMake(StickersListPadding,StickersListPadding,StickersListThumbSize-(StickersListPadding*2),StickersListThumbSize-(StickersListPadding*2))];

    photoView.image=image;
    photoView.contentMode=UIViewContentModeScaleAspectFit;
    photoView.userInteractionEnabled = YES;

    [cell.contentView addSubview:photoView];



    return cell;

非常适合将图像显示到单元格。

问题！

如果将页面滚动到底部，然后再次滚动回到顶部，则该单元格中的图像是重叠的。

如何解决。 （仅以编程方式使用单一视图）

Answer 1

我怀疑是因为您没有在UIImageView上设置框架，而是从其上设置的图像派生其大小。 因此，在某些情况下，它可能会溢出其父视图->单元格。

我建议您在UIImageView上设置一些约束，这可以通过编程来完成。 因此，尝试在UIIMageView上设置左，右，上和下约束，以使其停留在单元格的范围内

Answer 2

滚动期间

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath被重复调用。

这意味着您将UIImageView *photoView重复添加到cell.contentView

    UIImageView *photoView=[[UIImageView alloc]initWithFrame:CGRectMake(StickersListPadding,StickersListPadding,StickersListThumbSize-(StickersListPadding*2),StickersListThumbSize-(StickersListPadding*2))];

    //codes..

    [cell.contentView addSubview:photoView];

做这样的事情可以防止：

UICollectionViewCell *cell = [ColStickersListView dequeueReusableCellWithReuseIdentifier:@"CollStickersList" forIndexPath:indexPath];

if (cell == nil)
{
    UIImageView *photoView=[[UIImageView alloc]initWithFrame:CGRectMake(StickersListPadding,StickersListPadding,StickersListThumbSize-(StickersListPadding*2),StickersListThumbSize-(StickersListPadding*2))];

     // codes...

    [cell.contentView addSubview:photoView];
}

解决此问题的另一种方法是创建一个自定义收集单元：

// CustomCollectionCell.h
@interface YourCollectionCell : UICollectionViewCell

@property (nonatomic) UIImageView *photoView;

@end

// CustomCollectionCell.m

@implementation YourCollectionCell

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {

     // and setting up you imageview here
        self.photoView=[[UIImageView alloc]initWithFrame:YourRect];

        self.photoView.contentMode=UIViewContentModeScaleAspectFit;
        self.photoView.userInteractionEnabled = YES;

        [self.contentView addSubview:self.photoView];

    }
    return self;
}

并像这样使用它：

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
     CustomCollectionCell *cell = (CustomCollectionCell *)[ColStickersListView dequeueReusableCellWithReuseIdentifier:@"CollStickersList" forIndexPath:indexPath];

     cell.photoView.image=image;

     return cell;
}

希望我对您有所帮助，祝您编程愉快。