Question

在cellForRowAtIndexPath我正在向UIImageView添加cell.contentView。问题是当单元格从屏幕滚动并重新打开时，它会在已经存在的图像上再次添加相同的图像。这种情况持续发生，直到我得到一个非常叠加的模糊图像。

您是否必须继续删除添加到cell.contentView的所有图片视图？如果是这样，你使用什么委托方法？

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

    static NSString *CellIdentifier = @"CellIdentifier";

    MyTableCell *cell = (MyTableCell*)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"MyTableCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];
    }
    cell.selectionStyle = UITableViewCellSelectionStyleNone;

    UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"image.jpg"]];

    imageView.center = CGPointMake(310, 48);
    [cell.contentView addSubview:imageView];
    [imageView release];
    return cell;
}

Answer 1

如果您不想继续将imageView放在单元格中，则必须在if(cell==nil)块内进行所有自定义，否则每次单元回收时都会添加一个。使用单元格回收时，您总是希望保留该块中所有单元格的一致性，以便它们只添加一次。

例如：

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

    static NSString *CellIdentifier = @"CellIdentifier";

    MyTableCell *cell = (MyTableCell*)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"MyTableCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];

        //Add custom objects to the cell in here!
        UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"image.jpg"]];

        imageView.center = CGPointMake(310, 48);
        [cell.contentView addSubview:imageView];
        [imageView release];
    }
    cell.selectionStyle = UITableViewCellSelectionStyleNone;


    return cell;
}

Answer 2

如果每个单元格需要不同的图像，您可以尝试这样的方法：

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

    static NSString *CellIdentifier = @"CellIdentifier";
    static const int ImageViewTag = 1234; //any integer constant

    MyTableCell *cell = (MyTableCell*)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    UIImageView *imageView;
    if (cell == nil)
    {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"MyTableCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];

        //Add custom objects to the cell in here!
        imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0,0, imgWidth, imgHeight)];

        imageView.center = CGPointMake(310, 48);
        imageView.tag = ImageViewTag;
        [cell.contentView addSubview:imageView];
        [imageView release];
        cell.selectionStyle = UITableViewCellSelectionStyleNone;
    }
    else
    {
        imageView = [cell viewWithTag:ImageViewTag];
    }
    imageView.image = yourUIImageForThisCell;

    return cell;
}

uitableview - 自定义图像继续在cell.contentView中加载

2 个答案: