刷新某些行后，为什么表视图单元格会被搞乱？

Question

我正在使用UITableView列出来自Internet的一些图像。所以我使用AFNetworking'ssetImageWithURLRequest:placeholderImage:success:failure:方法，当图像下载时，我需要做一些过程然后显示。为了刷新处理后的图像，我使用

[wTableView beginUpdates]; 
[wTableView reloadRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath, nil] withRowAnimation:UITableViewRowAnimationNone]; 
[wTableView endUpdates]; 

在成功块。看来这个工程时加载的第一次，但是当我滚动tableview中，该行被搞砸了，还一个行消失，它很容易在[wTableView endUpdates];方法崩溃。这种方法有什么问题？ 相关的代码片段如下：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{ 
    static NSString *tableIdentifier = @"cell"; 

    CouponTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:tableIdentifier]; 

    if (!cell) { 
     cell = [[CouponTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:tableIdentifier]; 
    } 
    [cell prepareForReuse]; 

    NSArray *coupons = [mCoupons objectAtIndex:indexPath.section]; 
    CouponDB *couponDB = [coupons objectAtIndex:indexPath.row]; 
    NSString *thumbLink; 
    if (couponDB) { 
     [cell.textLabel setText:couponDB.couponInfo.company]; 
     [cell.textLabel setFont:[UIFont boldSystemFontOfSize:CELL_LABEL_FONT_SIZE]]; 
     [cell.textLabel setTextColor:[UIColor grayColor]]; 
     [cell.textLabel setBackgroundColor:[UIColor clearColor]]; 
     [cell.detailTextLabel setText:[NSString stringWithFormat:@"Expires:%@",couponDB.couponInfo.deadline]]; 
     [cell.detailTextLabel setBackgroundColor:[UIColor clearColor]]; 
     thumbLink = [self thumbLink:couponDB.couponInfo.imgURL]; 
     [cell setNeedsLayout]; 

     if (couponDB.redeem_status) { 
      UIImageView * __weak imageView = cell.imageView; 
      CouponTableController * __weak table = self; 
      UITableView *__weak wTableView = mTableView; 
      [cell.imageView setImageWithURLRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:thumbLink]] placeholderImage:nil success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) { 
       imageView.image = [table crossedImage:image]; 
       @synchronized(wTableView){ 
        [wTableView beginUpdates]; 
        [wTableView reloadRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath, nil] withRowAnimation:UITableViewRowAnimationNone]; 
        [wTableView endUpdates]; 
       } 

      } failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) { 
       NSLog(@"cell imageview load error:%@",error); 
      }]; 
     } else { 
      [cell.imageView setImageWithURL:[NSURL URLWithString:thumbLink] placeholderImage:[UIImage imageNamed:@"default_cover.jpg"]]; 
     } 

    } 

    if (![cell.backgroundView isKindOfClass:[CouponTableCellBackgroud class]]) { 
     cell.backgroundView = [[CouponTableCellBackgroud alloc] init]; 
    } 

    return cell; 
} 

首次正装表（无滚动）是这样的：

当您滚动向下和向上的表行搞砸了，这是象下面这样：

任何建议都理解的。

Answer 1

到

UIImageView * __weak imageView = cell.imageView; 
CouponTableController * __weak table = self; 
[cell.imageView setImageWithURLRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:thumbLink]] placeholderImage:[UIImage imageNamed:@"default_cover.jpg"] success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) { 
       imageView.image = [table crossedImage:image]; 
    } failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) { 
       NSLog(@"cell imageview load error:%@",error); 
    }]; 

只有添加一个占位符图像和删除的tableview更新。那么它会自动刷新单元格。

Answer 2

你可以试试这个：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{ 
     static NSString *SimpleTableIdentifier = @"YourResuseIdentifier"; 

     CouponTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:tableIdentifier]; 

    if(cell == nil) 
    { 
     cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:SimpleTableIdentifier]; 
    } 
    else 
    { 
     for (UIView *subview in cell.contentView.subviews) 
      [subview removeFromSuperview]; 
    } 


    NSArray *coupons = [mCoupons objectAtIndex:indexPath.section]; 
    CouponDB *couponDB = [coupons objectAtIndex:indexPath.row]; 
    NSString *thumbLink; 
    if (couponDB) { 
     [cell.textLabel setText:couponDB.couponInfo.company]; 
     [cell.textLabel setFont:[UIFont boldSystemFontOfSize:CELL_LABEL_FONT_SIZE]]; 
     [cell.textLabel setTextColor:[UIColor grayColor]]; 
     [cell.textLabel setBackgroundColor:[UIColor clearColor]]; 
     [cell.detailTextLabel setText:[NSString stringWithFormat:@"Expires:%@",couponDB.couponInfo.deadline]]; 
     [cell.detailTextLabel setBackgroundColor:[UIColor clearColor]]; 
     thumbLink = [self thumbLink:couponDB.couponInfo.imgURL]; 

     if (couponDB.redeem_status) { 
      UIImageView * __weak imageView = cell.imageView; 
      CouponTableController * __weak table = self; 
      UITableView *__weak wTableView = mTableView; 
      [cell.imageView setImageWithURLRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:thumbLink]] placeholderImage:nil success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) { 
       imageView.image = [table crossedImage:image]; 

       [wTableView beginUpdates]; 
       [wTableView reloadRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath, nil] withRowAnimation:UITableViewRowAnimationNone]; 
       [wTableView endUpdates]; 


      } failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) { 
       NSLog(@"cell imageview load error:%@",error); 
      }]; 
     } else { 
      [cell.imageView setImageWithURL:[NSURL URLWithString:thumbLink] placeholderImage:[UIImage imageNamed:@"default_cover.jpg"]]; 
     } 

    } 

    if (![cell.backgroundView isKindOfClass:[CouponTableCellBackgroud class]]) { 
     cell.backgroundView = [[CouponTableCellBackgroud alloc] init]; 
    } 

    return cell; 
} 

Answer 3

试试这个，而不是重装电池。声明一个弱指针，以我改变负载图像代码的单元格

__weak UITableViewCell *weakCell = cell; 
[cell.imageView setImageWithURLRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:thumbLink]] placeholderImage:nil success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) { 
      weakCell.imageView.image = [table crossedImage:image]; 
      [weakCell setNeedsLayout];     

} failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) { 
      NSLog(@"cell imageview load error:%@",error); 
}];