viewWithTag返回零在cellForRowAtIndexPath方法

Question

我有一个自定义原型单元格的UITableViewController。在原型单元格内有两个标签和一个图像。这些标签用100表示​​图像，101和102用于标签。我试图访问标签这种方法

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

    if ([indexPath row] == 0) { 
     static NSString *CellIdentifier = @"InfoCell"; 
     UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath]; 

     UIImageView *albumArtworkImageView = (UIImageView *)[cell viewWithTag:100]; 
     albumArtworkImageView.image = [self getAlbumArtworkWithSize:albumArtworkImageView.frame.size]; 

     UILabel *albumArtistLabel = (UILabel *)[cell viewWithTag:101]; 
     albumArtistLabel.text = [self getAlbumArtist]; 

     UILabel *albumInfoLabel = (UILabel *)[cell viewWithTag:102]; 
     albumInfoLabel.text = [self getAlbumInfo]; 

     return cell; 
    } else { 

     static NSString *CellIdentifier = @"Cell"; 
     UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath]; 


     MPMediaQuery *audiobookQuery = [MPMediaQuery audiobooksQuery]; 
     MPMediaPropertyPredicate *albumPredicate = [MPMediaPropertyPredicate predicateWithValue: audiobookTitle forProperty: MPMediaItemPropertyAlbumTitle]; 
     [audiobookQuery addFilterPredicate:albumPredicate]; 
     NSArray *albumTracks = [audiobookQuery items]; 

     NSUInteger trackNumber = [[[albumTracks objectAtIndex:(indexPath.row-1)] valueForProperty:MPMediaItemPropertyAlbumTrackNumber] unsignedIntegerValue]; 

     if (trackNumber) { 
      cell.textLabel.text = [NSString stringWithFormat:@"%i. %@", trackNumber, [[[albumTracks objectAtIndex:(indexPath.row-1)] representativeItem] valueForProperty:MPMediaItemPropertyTitle]]; 
     } else { 
      cell.textLabel.text = [[[albumTracks objectAtIndex:(indexPath.row-1)] representativeItem] valueForProperty:MPMediaItemPropertyTitle]; 
     } 


     if ([self sameArtists]) { 

      cell.detailTextLabel.text = @""; 

     } else { 

      if ([[[albumTracks objectAtIndex:(indexPath.row-1)] representativeItem] valueForProperty:MPMediaItemPropertyArtist]) { 
       cell.detailTextLabel.text = [[[albumTracks objectAtIndex:(indexPath.row-1)] representativeItem] valueForProperty:MPMediaItemPropertyArtist]; 
      } else { 
       cell.detailTextLabel.text = @""; 
      } 

     } 

     return cell; 
    } 
} 

继承人里面看看故事板

这个问题我有是我仰望的观点从标签的线返回零。我之前做过这种查找，但我无法弄清楚为什么他们返回零。任何帮助将非常感激。我甚至不确定调试的好方法。我是一名试图学习Objective-C/ios编程的C＃开发人员。谢谢！

Answer 1

我给你一个选择。为UITableViewCell定制课程并在那里宣布它的观点;然后将每个单元格的子视图与这些属性连接起来，并直接访问它们，而无需调用viewWithTag。

例如，在您的自定义单元格：

@interface MyCustomCell : UITableViewCell 

@property (strong, nonatomic) UIImageView *albumArtworkImageView; 
@property (strong, nonatomic) UILabel *albumArtistLabel; 
@property (strong, nonatomic) UILabel *albumInfoLabel; 

，并在您cellForRowAtIndexPath方法：

MyCustomCell *cell = (MyCustomCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath]; 
cell.albumArtworkImageView.image = [self getAlbumArtworkWithSize:albumArtworkImageView.frame.size]; 
cell.albumArtistLabel.text = [self getAlbumArtist]; 
cell.albumInfoLabel.text = [self getAlbumInfo]; 

记得设置MyCustomCell在故事板的细胞。

希望这会有所帮助！