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删除子视图并将其添加到自定义UITableViewCell

custom-cell uitableview objective-c ios

Davis · 技术社区 · 11 年前

我有一个自定义单元格,上面有不同的子视图。其中一个UIImageView是可选的。因此可能存在单元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的单元格的图像,以及如何为需要的单元格添加图像?我知道我只应该像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:

我忘了说我使用每个节只有一行的节,这就是我使用indexPath.Section的原因!

我从Web服务器获取所有数据,并将所有数据放入阵列self.newsList!

编辑2: 使用此代码,我可以获得正确单元格的正确图像,但在向下滚动和向上滚动后,所有内容都消失了:/

- (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];

        }
    }

5 回复 | 直到 11 年前

bhavya kothari 11 年前

尝试这种方法-在故事板中添加UIImageView,您可以在应用程序逻辑需要时隐藏和取消隐藏。

 - (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;
}

Bhumeshwer katre 11 年前

请使用此选项:

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

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

Samkit Jain 11 年前

您正在为节添加图像。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];

        }

Shankar BS 11 年前

通过这种方式尝试,如果条件符合以下要求,不要检查内部是否存在图像。希望这对您有所帮助,请根据您的要求进行更改

 - (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;
}

Bhavesh Nayi 11 年前

- (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];

                 }
                 }
                 }