图像在 UITableView 中混淆 - XML 解析 [英] Images getting mixed up in a UITableView - XML parsing

问题描述

实际上图像看起来不错，只是当我滚动时它们被混淆了......

我正在解析一个 XML 文件，其中包含指向我放入 UITable 的图像的链接.出于某种原因，图片变得完全混乱，当我向下滚动表格时，其中一些甚至开始发生变化！这是我用于 UITable 的代码:

I'm parsing an XML file with links to images which I'm putting into a UITable. For some reason the pictures are getting completely mixed up and when I scroll down the table some of them even start to change! Here's the code I'm using for my UITable:

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

    static NSString *CellIdentifier = @"Cell";
    Tweet *currentTweet = [[xmlParser tweets] objectAtIndex:indexPath.row];

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil)
    {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];

        CGRect imageFrame = CGRectMake(2, 8, 40, 40);
        customImage = [[UIImageView alloc] initWithFrame:imageFrame];
        [cell.contentView addSubview:customImage];

    }

    NSString *picURL = [currentTweet pic];
    if (![picURL hasPrefix:@"http:"]) {
        picURL = [@"http:" stringByAppendingString:picURL];
    }

    customImage.image = [UIImage imageWithData:[NSData dataWithContentsOfURL: [NSURL URLWithString:picURL]]];

    return cell;
}

知道我做错了什么吗?任何帮助都受到严重赞赏.谢谢！

Any idea what I'm doing wrong? Any help is seriously appreciated. Thx!

推荐答案

你的问题是如果单元格不是 nil (即你已经成功重用了一个已经滚出屏幕的单元格)，您没有正确设置 customImage 指针(因为它是一个类实例变量，它具有它创建的最后一个单元格的值).因此，为 kCustomImageTag 定义一些非零常量，然后将 cellForRowAtIndexPath 中的 if 语句修改为:

Your problem is that if the cell is not nil (i.e. you've successfully reused a cell that has scrolled off the screen), you're not setting the customImage pointer properly (since it is a class instance variable, it has the value from the last cell it created). So, define some non-zero constant for kCustomImageTag and then modify the if statement in cellForRowAtIndexPath to be:

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

    CGRect imageFrame = CGRectMake(2, 8, 40, 40);
    customImage = [[UIImageView alloc] initWithFrame:imageFrame];
    [cell.contentView addSubview:customImage];
    customImage.tag = kCustomImageTag;
}
else
{
    customImage = [cell.contentView viewWithTag:kCustomImageTag];
}

在创建 customImage 时设置 tag 并使用该 tag 检索重用的现有 customImageUITableViewCell.

Set the tag when you create customImage and use that tag to retrieve an existing customImage in the reused UITableViewCell.

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