iPhone:向单元格内容 View 添加 subview 会覆盖滚动时的单元格文本

Question

我在实现中使用了 Cell.ContentView 来自定义单元格内容。它工作正常，但唯一的问题是，当我有很多单元格并且我上下滚动它们时，单元格内容会被覆盖到单元格中，这些单元格变得隐藏，然后变得可见。假设我向上滚动第一个单元格，然后再次将其向下滚动，最后一个单元格的内容将被覆盖在第一个单元格上!!

我对此进行了足够的调试，但找不到确切的解决方案。我尝试检查 Cell.ContentView.SubViews 计数，如果为 0，则仅添加其他 subview 。在我上下滚动它们之前，它不会显示任何单元格内容，但是一旦内容出现，它就不会覆盖..有点奇怪..!我还确保我正确地重复使用了电池。以下是我的代码，它将 subview 添加到单元格的内容 View 中。请让我知道如何解决这个问题。

P.S:不要担心我所做的变量和计算。假设它返回正确的值。 :)

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

    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

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

    NSInteger totalAvailableSpace = IPHONE_DISPLAY_WIDTH - iconSize - accesorySize - 10;
    NSInteger lableHeight = [[cellDetails objectForKey:@"TableItemTextFontSize"] intValue] * 2 + 10;

    UILabel *textLabel = nil;
    textLabel = [[[UILabel alloc] initWithFrame:CGRectMake(iconSize+12, self.tableCellHeight/2 - lableHeight/2, totalAvailableSpace * 0.8, lableHeight)] autorelease];
    textLabel.numberOfLines = 2;
    textLabel.lineBreakMode = UILineBreakModeWordWrap;
    textLabel.textAlignment = UITextAlignmentLeft;
    textLabel.text = [cellDetails objectForKey:@"TableItemMainText"];
    if ([textLableColor scanHexInt:&hex]) {
        textLabel.textColor = UIColorFromRGB(hex);
    }
    textLabel.font = [UIFont fontWithName:[cellDetails objectForKey:@"TableItemTextFontName"] size:[[cellDetails objectForKey:@"TableItemTextFontSize"] intValue]]; 
    [cell.contentView addSubview:textLabel];
    textLabel.backgroundColor = [UIColor clearColor];

    lableHeight = [[cellDetails objectForKey:@"TableItemDetailTextFontSize"] intValue] * 2 + 10;
    UILabel *detailTextLabel = nil;
    detailTextLabel = [[[UILabel alloc] initWithFrame:CGRectMake(iconSize+10+totalAvailableSpace * 0.8+5, self.tableCellHeight/2 - lableHeight/2, totalAvailableSpace * 0.2 - 10, lableHeight)] autorelease];
    detailTextLabel.numberOfLines = 2;
    detailTextLabel.lineBreakMode = UILineBreakModeWordWrap;
    detailTextLabel.textAlignment = UITextAlignmentLeft;
    detailTextLabel.text = [cellDetails objectForKey:@"TableItemDetailText"];
    if ([detailTextLableColor scanHexInt:&hex]) {
        detailTextLabel.textColor = UIColorFromRGB(hex);
    }
    detailTextLabel.font = [UIFont fontWithName:[cellDetails objectForKey:@"TableItemDetailTextFontName"] size:[[cellDetails objectForKey:@"TableItemDetailTextFontSize"] intValue]];
    [cell.contentView addSubview:detailTextLabel];
    detailTextLabel.backgroundColor = [UIColor clearColor];

    return cell;
}

谢谢。

Answer 1

这是因为玩具会一遍又一遍地将 View 添加到您的单元格中。

您应该仅在创建单元格时添加它们，并在重用单元格时设置标签。

您可以为标签设置标签，以便之后可以设置它的文本。下面的代码就可以解决问题

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

    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {
        if(style == UITableViewCellStyleValue1)
            cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
        else
            cell = [[[UITableViewCell alloc] initWithStyle:style reuseIdentifier:CellIdentifier] autorelease];


        NSInteger totalAvailableSpace = IPHONE_DISPLAY_WIDTH - iconSize - accesorySize - 10;
        NSInteger lableHeight = [[cellDetails objectForKey:@"TableItemTextFontSize"] intValue] * 2 + 10;

        UILabel *textLabel = nil;
        textLabel.tag = 1;
        textLabel = [[[UILabel alloc] initWithFrame:CGRectMake(iconSize+12, self.tableCellHeight/2 - lableHeight/2, totalAvailableSpace * 0.8, lableHeight)] autorelease];
        textLabel.numberOfLines = 2;
        textLabel.lineBreakMode = UILineBreakModeWordWrap;
        textLabel.textAlignment = UITextAlignmentLeft;
        textLabel.text = [cellDetails objectForKey:@"TableItemMainText"];
        if ([textLableColor scanHexInt:&hex]) {
            textLabel.textColor = UIColorFromRGB(hex);
        }
        textLabel.font = [UIFont fontWithName:[cellDetails objectForKey:@"TableItemTextFontName"] size:[[cellDetails objectForKey:@"TableItemTextFontSize"] intValue]]; 
        [cell.contentView addSubview:textLabel];
        textLabel.backgroundColor = [UIColor clearColor];

        lableHeight = [[cellDetails objectForKey:@"TableItemDetailTextFontSize"] intValue] * 2 + 10;
        UILabel *detailTextLabel = nil;
        detailTextLabel.tag = 2;
        detailTextLabel = [[[UILabel alloc] initWithFrame:CGRectMake(iconSize+10+totalAvailableSpace * 0.8+5, self.tableCellHeight/2 - lableHeight/2, totalAvailableSpace * 0.2 - 10, lableHeight)] autorelease];
        detailTextLabel.numberOfLines = 2;
        detailTextLabel.lineBreakMode = UILineBreakModeWordWrap;
        detailTextLabel.textAlignment = UITextAlignmentLeft;
        detailTextLabel.text = [cellDetails objectForKey:@"TableItemDetailText"];
        if ([detailTextLableColor scanHexInt:&hex]) {
            detailTextLabel.textColor = UIColorFromRGB(hex);
        }
        detailTextLabel.font = [UIFont fontWithName:[cellDetails objectForKey:@"TableItemDetailTextFontName"] size:[[cellDetails objectForKey:@"TableItemDetailTextFontSize"] intValue]];
        [cell.contentView addSubview:detailTextLabel];
        detailTextLabel.backgroundColor = [UIColor clearColor];

    } else {

        UILabel *textLabel = (UILabel *)[cell viewWithTag:1];
        textLabel.text = [cellDetails objectForKey:@"TableItemMainText"];

        UILabel *detailTextLabel = (UILabel *)[cell viewWithTag:2];
        detailTextLabel.text = [cellDetails objectForKey:@"TableItemDetailText"];

    }

    return cell;
}