UITableViewCell显示滚动后第一个单元格。

Question

我创建了一个表，其中单元格的大小会根据填充它们的内容量而动态变化。 我遇到的问题是，当我向下滚动然后再次备份时，第一个单元格添加了不应该存在的内容。

这是一个显示我的问题的视频。

这是我用来尝试实现它的代码。

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


    static NSString *CellIdentifier = @"Cell";
    //NotificationCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];

    if (cell == nil)
    {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }

    noteBody = [Noifications objectAtIndex:indexPath.row];
    yPosition = 10;
    NSLog(@"noteBody: %@",noteBody);

    double titleHeight = 0;
    NSUInteger titleLenght = [noteBody objectForKey:@"title"];

    if (titleLenght < 30)titleHeight = 25;
    else if(titleLenght < 60)titleHeight = 50;
    else if(titleLenght < 90)titleHeight = 75;
    else if(titleLenght < 120)titleHeight = 100;
    else if(titleLenght < 150)titleHeight = 125;
    else if(titleLenght < 180)titleHeight = 150;
    else titleHeight = 200;


    UILabel *Title = [[UILabel alloc]initWithFrame:CGRectMake(10, yPosition, self.view.frame.size.width-30, titleHeight)];
    Title.text = [noteBody objectForKey:@"title"];
    Title.font = [UIFont boldSystemFontOfSize:20];
    Title.textAlignment = NSTextAlignmentCenter;
    Title.numberOfLines = 0;
    [Title sizeToFit];
    yPosition += Title.frame.size.height;
    [cell addSubview:Title];

    UILabel *Date = [[UILabel alloc]initWithFrame:CGRectMake(10, yPosition, self.view.frame.size.width-30, 25)];
    Date.text = [noteBody objectForKey:@"date"];
    Date.numberOfLines = 0;
    [Title sizeToFit];
    yPosition += Date.frame.size.height;
    [cell addSubview:Date];

    double bodyHeight = 0;
    NSUInteger bodyLenght = [noteBody objectForKey:@"title"];

    if (bodyLenght < 30)titleHeight = 25;
    else if(bodyHeight < 60)titleHeight = 50;
    else if(bodyHeight < 90)titleHeight = 75;
    else if(bodyHeight < 120)titleHeight = 100;
    else if(bodyHeight < 150)titleHeight = 125;
    else if(bodyHeight < 180)titleHeight = 150;
    else if(bodyHeight < 210)titleHeight = 175;
    else if(bodyHeight < 240)titleHeight = 200;
    else if(bodyHeight < 270)titleHeight = 225;
    else if(bodyHeight < 300)titleHeight = 250;
    else if(bodyHeight < 330)titleHeight = 275;
    else if(bodyHeight < 360)titleHeight = 300;
    else if(bodyHeight < 390)titleHeight = 325;
    else bodyHeight = 350;


    UILabel *Body = [[UILabel alloc]initWithFrame:CGRectMake(10, yPosition, self.view.frame.size.width-30, bodyHeight)];
    Body.text = [noteBody objectForKey:@"body"];
    Body.numberOfLines = 0;
    [Body sizeToFit];
    yPosition += Body.frame.size.height;
    [cell addSubview:Body];



    return cell;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    noteBodyCellHeight = [Noifications objectAtIndex:indexPath.row];

    NSLog(@"cellHeights: %@",cellHeights);

    NSString *title = [noteBodyCellHeight objectForKey:@"title"];
    NSString *date = [noteBodyCellHeight objectForKey:@"date"];
    NSString *body = [noteBodyCellHeight objectForKey:@"body"];

    CGRect frame = [UIScreen mainScreen].bounds;
    CGFloat width = frame.size.width;

    int section = indexPath.section;


    CGSize title_size = {0, 0};
    CGSize date_size = {0, 0};
    CGSize body_size = {0, 0};

    if (title && [title isEqualToString:@""] == NO ) {
        title_size = [title sizeWithFont:[UIFont systemFontOfSize:22.0]
                              constrainedToSize:CGSizeMake(width, 4000)
                                  lineBreakMode:UILineBreakModeWordWrap];
    }

    if (date && [date isEqualToString:@""] == NO ) {
        date_size = [date sizeWithFont:[UIFont systemFontOfSize:18.0]
                       constrainedToSize:CGSizeMake(width, 4000)
                           lineBreakMode:UILineBreakModeWordWrap];
    }

    if (body && [body isEqualToString:@""] == NO ) {
        body_size = [body sizeWithFont:[UIFont systemFontOfSize:18.0]
                                constrainedToSize:CGSizeMake(width, 4000)
                                    lineBreakMode:UILineBreakModeWordWrap];
    }

    CGFloat title_height = title_size.height;
    CGFloat date_height = date_size.height;
    CGFloat body_height = body_size.height;

    //CGFloat content_size = Body.frame.size.height + Title.frame.size.height + Date.frame.size.height;
    CGFloat content_size = title_height + date_height + body_height +20;
    NSLog(@"content_size: %f",content_size);
    CGFloat height;

    switch ( section ) {

        case 0:
            height = content_size;
            break;

            //Just in case
        default:
            height = 44.0;
            break;

    }

    return height;


}

谁能告诉我哪里出错了，并指出我如何解决这个问题？

Answer 1

尝试使用自定义单元格类或在重用时删除单元格现有子视图。

基本上每次调用cellForRow ..子视图都会被添加到单元格中，即使它正被重用。

 if (cell == nil)
    {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }

在上面添加之后

for(UIView *view in cell.contentView.subviews)
{
  [view removeFromSuperView];
}

还将cell addSubview更改为cell.contentView addSubview

Answer 2

您可能只想将三个子视图添加到单元格中一次，为每个子视图添加一个唯一标记，即在if块中初始化之后。 之后，您可以在单元格上使用-viewWithTag:来引用标签并设置其大小和内容。