UITableViewCell图像在滚动时发生变化 [英] UITableViewCell image changes when scrolling

问题描述

我有一个带有标题和每个单元格上的图像的UITableView.一些单元格将具有默认图像，而其他单元格则没有.当我滚动表格时，某些行的图像不是预期的，而是显示另一行的图像，而不是预期的图像.如果我不使用dequeuereuseidentifier，那么一切都会很好，但是我想使用它，因为我有很多单元格.

有什么建议吗?

 <代码>-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{UITableViewCell * cell = [tableView dequeueReusableCellWithIdentifier:@"MyCell"]；if(cell == nil){单元格= [[UITableViewCell分配] initWithStyle:UITableViewCellStyleDefault重用标识符:@"MyCell"]；CGRect titleRect = CGRectMake(60，6，200，24);UILabel * title = [[UILabel alloc] initWithFrame:titleRect];title.tag = 1;title.backgroundColor = [UIColor clearColor];title.font = [UIFont fontWithName:@"AdelleBasic-Bold" size:15.5];[cell.contentView addSubview:title];UIImageView * defaultCellImage = [[UIImageView分配] initWithFrame:CGRectMake(8，10，42，42)];defaultCellImage.tag = 2;[defaultCellImage setImage:[UIImage imageNamed:@"Default_Row_Image"]]];[cell.contentView addSubview:defaultCellImage];}NSUInteger行= [indexPath行];电影*电影= [_movies objectAtIndex:row];UILabel * titleRowLabel =(UILabel *)[cell.contentView viewWithTag:1];titleRowLabel.text = [电影标题];UIImageView * cellImage =(UIImageView *)[cell.contentView viewWithTag:2];如果(！[movie.imageName isEqualToString:@"])[cellImage setImage:[UIImage imageNamed:[电影imageName]]]];返回单元} 

解决方案

将正确加载表视图中要使用的第一个单元格.由于没有要出队的单元格，因此 if(cell == nil)将返回 YES ，并且您的单元格将其图像设置为默认图像.然后，如果稍后在该方法中满足您设置其他图像的条件，则将显示其他图像.到目前为止，一切都很好.

但是，当可重复使用的单元格出队时，它已经设置了映像，这可能不是默认设置.由于 cell == nil 现在将返回 NO ，因此即使应显示该图像，该单元也永远不会将其图像重置为默认图像.

I have a UITableView with a title and an image on each cell. Some cells will have a default image and others will not. When I scroll the table, the image of some rows is not the expected and the image of another row gets displayed instead of the expected one. If I don't use dequeuereuseidentifier everything works fine, but I want to use it because I have lots of cells.

Any suggestion?

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

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"MyCell"];

    if (cell == nil) {
        cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"MyCell"];

        CGRect titleRect = CGRectMake(60, 6, 200, 24);
        UILabel *title = [[UILabel alloc] initWithFrame: titleRect];
        title.tag = 1;
        title.backgroundColor = [UIColor clearColor];
        title.font = [UIFont fontWithName:@"AdelleBasic-Bold" size:15.5];
        [cell.contentView addSubview:title];

        UIImageView *defaultCellImage = [[UIImageView alloc] initWithFrame:CGRectMake(8, 10, 42, 42)];
        defaultCellImage.tag = 2;
        [defaultCellImage setImage:[UIImage imageNamed: @"Default_Row_Image"]];
        [cell.contentView addSubview:defaultCellImage];
    }

    NSUInteger row = [indexPath row];
    Movie *movie = [_movies objectAtIndex: row];

    UILabel *titleRowLabel = (UILabel *) [cell.contentView viewWithTag:1];
    titleRowLabel.text = [movie title];

    UIImageView *cellImage = (UIImageView *) [cell.contentView viewWithTag:2];
    if (![movie.imageName isEqualToString:@""])
        [cellImage setImage:[UIImage imageNamed: [movie imageName]]];

    return cell;
}

解决方案

The first cells to be used in your table view will be properly loaded. Since there is no cell to dequeue, the if (cell == nil) will return YES and your cell will have its image set to be the default. Then, if your condition for setting a different image is satisfied later in the method, a different image will be shown. So far, so good.

However, when a reusable cell is dequeued, it already has an image set, which might not be the default. Since cell == nil will now return NO, this cell will never have its image reset to the default one, even if it is the image that should be shown.

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