删除并将子视图添加到自定义UITableViewCell

Question

我有一个带有不同子视图的自定义单元格。 其中之一，UIImageView是可选的。 因此可能会出现单元格中不需要图像的情况。 我的问题是我不知道如何删除不需要它的单元格的图像，以及如何为需要它的单元格添加图像？ 我知道我只应该这样添加和删除子视图：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{

static NSString *CellIdentifier1 = @"NewsCell";

    GTNewsCustomCell *newsCell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier1];

    if(newsCell == nil){

        newsCell = [[GTNewsCustomCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier1];

       //Here i get the Image from my Array (self.newsList)
        NSString *boardImg = [[self.newsList objectAtIndex:indexPath.section] valueForKey:@"boardnoteImage"];

        //Here im checkin if an image exists
        if(boardImg == (NSString *)[NSNull null] || boardImg == nil || boardImg.length == 0){

            //If no Image exists remove the subview
            [newsCell.boardNoteImage removeFromSuperview];

        } else {

            //If an image exists, check if the subview is already added
            if(![newsCell.boardNoteImage isDescendantOfView:newsCell.contentView ]) {
                [newsCell.contentView addSubview:[newsCell.boardNoteImage];

        }
    }
}

但这不起作用，因为现在我在每个单元格上都得到了相同的图像……

编辑：

对不起，我忘了说我在使用Section，每个部分只有一行，这就是我使用indexPath.section的原因！

我从网络服务器获取所有数据，并将所有内容放入数组self.newsList！

EDIT2：使用此代码，我可以获得正确的单元格的正确图像，但是向下滚动并向上备份之后，一切都消失了：/

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{

static NSString *CellIdentifier1 = @"NewsCell";

    GTNewsCustomCell *newsCell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier1];

    if(newsCell == nil){

        newsCell = [[GTNewsCustomCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier1];

    }

    NSString *boardImg = [[self.newsList objectAtIndex:indexPath.section] valueForKey:@"boardnoteImage"];

    if(boardImg == (NSString *)[NSNull null] || boardImg == nil || boardImg.length == 0){

        [newsCell.boardNoteImage removeFromSuperview];
        newsCell.boardNoteImage.image = nil;
    } else {

        if(![newsCell.boardNoteImage isDescendantOfView:newsCell.contentView ]) {

            newsCell.boardNoteImage.frame = CGRectMake(newsCell.boardNoteImage.frame.origin.x, newsCell.boardNoteImage.frame.origin.y, newsCell.boardNoteImage.frame.size.width, newsCell.boardNoteImage.frame.size.height);

            [newsCell.contentView addSubview:newsCell.boardNoteImage];

        }
    }

Answer 1

尝试这种方法-在情节提要中添加UIImageView，只要您需要应用逻辑就可以隐藏和取消隐藏。

 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
   GTNewsCustomCell *cell = [tableView dequeueReusableCellWithIdentifier:@"SongCell"];
   if(cell == nil)
  {
     cell = [[CustomCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"SongCell"];
     //dont check the presence of image in this part becz it is called during creation only not on resuing
  }
  //check if image is present or not
  NSString *boardImg = [[self.newsList objectAtIndex:indexPath.row] valueForKey:@"boardnoteImage"];
   if(boardImg)
   {
      //image is present
     cell.boardNoteImage.hidden = NO;

      cell.boardNoteImage.image = boardImg;


   }
   else
   {
     cell.boardNoteImage.frame = CGRectZero;//which places a zero rect means no image
     cell.boardNoteImage.hidden = YES;

   }

 return cell;
}

Answer 2

请使用这个：

NSString *boardImg = [[self.newsList objectAtIndex:indexPath.row] valueForKey:@"boardnoteImage"];

您需要使用indexPath.row而不是indexPath.section

Answer 3

您正在添加图像的部分。 因此，请执行以下操作：

NSString *boardImg = [[self.newsList objectAtIndex:indexPath.row] valueForKey:@"boardnoteImage"];

  if(boardImg == (NSString *)[NSNull null] || boardImg == nil || boardImg.length == 0){
       //If no Image exists remove the subview
        [newsCell.boardNoteImage removeFromSuperview];
        newsCell.boardNoteImage = nil;

    } else {
            //set the frames here if required
            [newsCell addSubview:boardNoteImage];
    }

编辑1：

    if(boardImg == (NSString *)[NSNull null] || boardImg == nil || boardImg.length == 0){

        [newsCell.boardNoteImage removeFromSuperview];
        newsCell.boardNoteImage.image = nil;
    } else {

        if(![newsCell.boardNoteImage isDescendantOfView:newsCell.contentView ]) {

            newsCell.boardNoteImage = [[UIImageView alloc] init];

            // SET THE IMAGE HERE

            newsCell.boardNoteImage.frame = CGRectMake(newsCell.boardNoteImage.frame.origin.x, newsCell.boardNoteImage.frame.origin.y, newsCell.boardNoteImage.frame.size.width, newsCell.boardNoteImage.frame.size.height);

            [newsCell.contentView addSubview:newsCell.boardNoteImage];

        }

Answer 4

尝试这种方式，如果情况如下所示，请不要检查内部图像是否存在，希望对您有所帮助，将其更改为您的要求

 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
   GTNewsCustomCell *cell = [tableView dequeueReusableCellWithIdentifier:@"SongCell"];
   if(cell == nil)
  {
     cell = [[CustomCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"SongCell"];
     //dont check the presence of image in this part becz it is called during creation only not on resuing
  }
  //check if image is present or not
  NSString *boardImg = [[self.newsList objectAtIndex:indexPath.row] valueForKey:@"boardnoteImage"];
   if(boardImg)
   {
      //image is present
      cell.boardNoteImage.image = boardImg;


   }
   else
   {
     cell.boardNoteImage.frame = CGRectZero;//which places a zero rect means no image
     cell.boardNoteImage. hidden = YES;//place a nil in the image

   }

 return cell;
}

Answer 5

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{

    //static NSString *CellIdentifier1 = @"NewsCell";
    NSString *CellIdentifier1 = [NSString stringWithFormat:@"cell %d",indexPath.row];

    GTNewsCustomCell *newsCell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier1];

    newsCell = nil;
    if(newsCell == nil)
    {

        newsCell = [[GTNewsCustomCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier1];

        //Here i get the Image from my Array (self.newsList)
        NSString *boardImg = [[self.newsList objectAtIndex:indexPath.section] valueForKey:@"boardnoteImage"];

        //Here im checkin if an image exists
        if(boardImg == (NSString *)[NSNull null] || boardImg == nil || boardImg.length == 0){

            //If no Image exists remove the subview
            [newsCell.boardNoteImage removeFromSuperview];

        } else {

            //If an image exists, check if the subview is already added
            if(![newsCell.boardNoteImage isDescendantOfView:newsCell.contentView ]) {
                [newsCell.contentView addSubview:[newsCell.boardNoteImage];

                 }
                 }
                 }