ios - CollectionView 中的标签重叠

Question

我已经用图像和标签实现了 Collection View 。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

问题是因为细胞被重复使用。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.创建 UIImage s 和 UILabel s 当单元格在子类上初始化时。安上cellForItemAtIndexPath使用 UIImage s 和 UILabel s 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 subview 。

- (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;
}