CollectionView 中的标签重叠

Question

我已经使用图像和标签实现了集合视图。图像工作正常，但标签重叠。我已经实现了所有必需的方法，但找不到标签重叠的问题。下面提供了我的代码

 - (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return 40;
}
//loading data
    - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:@"cellIdentifier" forIndexPath:indexPath];

   aProduct=[featuredProductsArray objectAtIndex:indexPath.row];
    UIImageView* imageView=[[UIImageView alloc]initWithFrame:CGRectMake(10, 10, cell.frame.size.width-20, cell.frame.size.width-20)];
    //imageView.image=[UIImage imageNamed:@"ad_share.png"];
    NSString* imageUrl=[aProduct.SmallImageLists firstObject];

    [imageView sd_setImageWithURL:[NSURL URLWithString:imageUrl]
             placeholderImage:[UIImage imageNamed:@"ad_share.png"]];

    [cell addSubview:imageView];

    UILabel *lblTitle=[[UILabel alloc]initWithFrame:CGRectMake(5, cell.frame.size.height-60, cell.frame.size.width, 30)];
    lblTitle.text=aProduct.DealTitle;
    lblTitle.font=[UIFont fontWithName:@"HelveticaNeue-Thin" size:12.0];
     lblTitle.textAlignment=NSTextAlignmentCenter;
    [cell addSubview:lblTitle];



    UILabel *lblPrice=[[UILabel alloc]initWithFrame:CGRectMake(5, cell.frame.size.height-30, cell.frame.size.width, 30)];
    lblPrice.text=aProduct.DealPrice;
    lblPrice.font=[UIFont fontWithName:@"HelveticaNeue-Bold" size:12.0];
     lblPrice.textAlignment=NSTextAlignmentCenter;
    [cell addSubview:lblPrice];


    cell.backgroundColor=[UIColor colorWithRed:228.0/255.0 green:228.0/255.0 blue:228.0/255.0 alpha:0.5];
    [cell.layer setCornerRadius:5.0f];
    [cell.layer setBorderColor:[UIColor lightGrayColor].CGColor];
    [cell.layer setBorderWidth:0.2f];
    [cell.layer setShadowColor:[UIColor colorWithRed:225.0/255.0 green:228.0/255.0 blue:228.0/255.0 alpha:1.0].CGColor];
    [cell.layer setShadowOpacity:1.0];
    [cell.layer setShadowRadius:5.0];
    [cell.layer setShadowOffset:CGSizeMake(5.0f, 5.0f)];

    return cell;
}

    - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    return CGSizeMake(self.view.frame.size.width/2-10, self.view.frame.size.width/2+30);
}

截图如下

Answer 1

问题在于细胞被重复使用。每次重复使用它们时，您都会在单元格上添加更多标签和图像。这就是为什么您会看到标签重叠的原因。

在我看来，有两种方法可以解决它：

• 创建UICollectionViewCell 的子类。在子类上初始化单元格时创建UIImages 和UILabels。在cellForItemAtIndexPath 上使用UIImages 和UILabels 而无需再次初始化它们。例如

  - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
  {
    UICollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:@"cellIdentifier" forIndexPath:indexPath];
  
    aProduct=[featuredProductsArray objectAtIndex:indexPath.row];
  
    NSString* imageUrl=[aProduct.SmallImageLists firstObject];
  
    [cell.imageView sd_setImageWithURL:[NSURL URLWithString:imageUrl]
      placeholderImage:[UIImage imageNamed:@"ad_share.png"]];
  
    cell.lblTitle.text=aProduct.DealTitle;
    cell.lblTitle.font=[UIFont fontWithName:@"HelveticaNeue-Thin" size:12.0];
    cell.lblTitle.textAlignment=NSTextAlignmentCenter;
  
  
    cell.lblPrice.text=aProduct.DealPrice;
    cell.lblPrice.font=[UIFont fontWithName:@"HelveticaNeue-Bold" size:12.0];
    cell.lblPrice.textAlignment=NSTextAlignmentCenter;
  
  
    cell.backgroundColor=[UIColor colorWithRed:228.0/255.0 green:228.0/255.0 blue:228.0/255.0 alpha:0.5];
    [cell.layer setCornerRadius:5.0f];
    [cell.layer setBorderColor:[UIColor lightGrayColor].CGColor];
    [cell.layer setBorderWidth:0.2f];
    [cell.layer setShadowColor:[UIColor colorWithRed:225.0/255.0 green:228.0/255.0 blue:228.0/255.0 alpha:1.0].CGColor];
    [cell.layer setShadowOpacity:1.0];
    [cell.layer setShadowRadius:5.0];
    [cell.layer setShadowOffset:CGSizeMake(5.0f, 5.0f)];
  
    return cell;
  }
  

• 另一种方法是在重用时删除单元格的子视图。

  - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
  {
    UICollectionViewCell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:@"cellIdentifier" forIndexPath:indexPath];
  
    // Remove subviews
    for (UIView *v in cell.contentView.subviews) {
      [v removeFromSuperview];
    }
  
    aProduct=[featuredProductsArray objectAtIndex:indexPath.row];
    UIImageView* imageView=[[UIImageView alloc]initWithFrame:CGRectMake(10, 10, cell.frame.size.width-20, cell.frame.size.width-20)];
    //imageView.image=[UIImage imageNamed:@"ad_share.png"];
    NSString* imageUrl=[aProduct.SmallImageLists firstObject];
  
    [imageView sd_setImageWithURL:[NSURL URLWithString:imageUrl]
      placeholderImage:[UIImage imageNamed:@"ad_share.png"]];
  
    [cell addSubview:imageView];
  
    UILabel *lblTitle=[[UILabel alloc]initWithFrame:CGRectMake(5, cell.frame.size.height-60, cell.frame.size.width, 30)];
    lblTitle.text=aProduct.DealTitle;
    lblTitle.font=[UIFont fontWithName:@"HelveticaNeue-Thin" size:12.0];
    lblTitle.textAlignment=NSTextAlignmentCenter;
    [cell addSubview:lblTitle];
  
  
  
    UILabel *lblPrice=[[UILabel alloc]initWithFrame:CGRectMake(5, cell.frame.size.height-30, cell.frame.size.width, 30)];
    lblPrice.text=aProduct.DealPrice;
    lblPrice.font=[UIFont fontWithName:@"HelveticaNeue-Bold" size:12.0];
    lblPrice.textAlignment=NSTextAlignmentCenter;
    [cell addSubview:lblPrice];
  
  
    cell.backgroundColor=[UIColor colorWithRed:228.0/255.0 green:228.0/255.0 blue:228.0/255.0 alpha:0.5];
    [cell.layer setCornerRadius:5.0f];
    [cell.layer setBorderColor:[UIColor lightGrayColor].CGColor];
    [cell.layer setBorderWidth:0.2f];
    [cell.layer setShadowColor:[UIColor colorWithRed:225.0/255.0 green:228.0/255.0 blue:228.0/255.0 alpha:1.0].CGColor];
    [cell.layer setShadowOpacity:1.0];
    [cell.layer setShadowRadius:5.0];
    [cell.layer setShadowOffset:CGSizeMake(5.0f, 5.0f)];
  
    return cell;
  }
  

Answer 2

你已经得到了答案。但是另一种解决方案是，因为每次您创建 UILabel 的新实例并将其添加到可重用单元格时，这就是问题的原因。使用 viewwithtag 也应该适用于您的情况。例如。

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

aProduct=[featuredProductsArray objectAtIndex:indexPath.row];

UIImageView* imageView = [cell viewWithTag:10];
if (imageView == nil) {
    imageView = [[UIImageView alloc]initWithFrame:CGRectMake(10, 10, cell.frame.size.width-20, cell.frame.size.width-20)];
    imageView.tag = 10;
    [cell addSubview:imageView];

}
imageView.image=[UIImage imageNamed:@"ad_share.png"];
NSString* imageUrl=[aProduct.SmallImageLists firstObject];

[imageView sd_setImageWithURL:[NSURL URLWithString:imageUrl]
             placeholderImage:[UIImage imageNamed:@"ad_share.png"]];



UILabel *lblTitle = [cell viewWithTag:20];

if (lblTitle == nil) {
    lblTitle=[[UILabel alloc]initWithFrame:CGRectMake(5, cell.frame.size.height-60, cell.frame.size.width, 30)];
    lblTitle.tag = 20;
    [cell addSubview:lblTitle];

}

lblTitle.text= aProduct.DealTitle;
lblTitle.font=[UIFont fontWithName:@"HelveticaNeue-Thin" size:12.0];
lblTitle.textAlignment=NSTextAlignmentCenter;



UILabel *lblPrice = [cell viewWithTag:30];

if (lblPrice == nil) {
    lblPrice=[[UILabel alloc]initWithFrame:CGRectMake(5, cell.frame.size.height-30, cell.frame.size.width, 30)];
    lblPrice.tag = 30;
    [cell addSubview:lblPrice];

}

lblPrice.text= aProduct.DealPrice;
lblPrice.font=[UIFont fontWithName:@"HelveticaNeue-Bold" size:12.0];
lblPrice.textAlignment=NSTextAlignmentCenter;


cell.backgroundColor=[UIColor colorWithRed:228.0/255.0 green:228.0/255.0 blue:228.0/255.0 alpha:0.5];
[cell.layer setCornerRadius:5.0f];
[cell.layer setBorderColor:[UIColor lightGrayColor].CGColor];
[cell.layer setBorderWidth:0.2f];
[cell.layer setShadowColor:[UIColor colorWithRed:225.0/255.0 green:228.0/255.0 blue:228.0/255.0 alpha:1.0].CGColor];
[cell.layer setShadowOpacity:1.0];
[cell.layer setShadowRadius:5.0];
[cell.layer setShadowOffset:CGSizeMake(5.0f, 5.0f)];

return cell;



}