为什么sizeToFit删除我的整个标签？

我想使用函数sizeToFit。它在整个应用程序中都能正常工作，但它在下面的代码中不起作用。除此之外，如果不能像我这样做，请告知。为什么sizeToFit删除我的整个标签？

  self.label = [[UILabel alloc] initWithFrame:CGRectMake(10.0, 67.0, 290, 50)]; 
     self.label.font= [UIFont fontWithName:@"Helvetica-Bold" size:20]; 
     self.label.textColor = [UIColor colorWithRed:33.0f/255.0f green:74.0f/255.0f blue:146.0f/255.0f alpha:1.0f]; 
     self.label.numberOfLines = 0; 
     self.label.lineBreakMode = NSLineBreakByWordWrapping; 
     self.label.backgroundColor = [UIColor whiteColor]; 
     [self.contentView addSubview:self.label]; 

     self.description = [[UILabel alloc] initWithFrame:CGRectMake(10.0, 380.0, 300, 400)]; 
     self.description.font= [UIFont fontWithName:@"Helvetica-Light" size:15]; 
     self.description.textColor = [UIColor blackColor]; 
     self.description.textAlignment = NSTextAlignmentJustified; 
     self.description.numberOfLines = 0; 
     self.description.lineBreakMode = NSLineBreakByWordWrapping; 
     self.description.backgroundColor = [UIColor whiteColor]; 
     [self.description sizeToFit]; 
     [self.contentView addSubview:self.description]; 


     self.image = [[UIImageView alloc] initWithFrame:CGRectMake(20, 130, 280, 228)]; 
     self.image.clipsToBounds = YES; 
     //[scrollView addSubview:self.image]; 
     [self.contentView addSubview:self.image]; 



     self.backgroundColor = [UIColor whiteColor];

我从不同的控制器通过使用该方法的数据

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath 
{ 
    Cell *cell=[collectionView dequeueReusableCellWithReuseIdentifier:@"Cell" forIndexPath:indexPath]; 
    NSDictionary *item = [_articleListmain objectAtIndex:indexPath.item]; 
    // set the article image 
    [cell.image setImageWithURL:[item objectForKey:@"image"]]; 
    [cell.label setText:[item objectForKey:@"title"]]; 
    [cell.description setText:[item objectForKey:@"description"]]; 



     return cell; 
}

来源

2013-10-09 Robert Farr