如何檢查值是來自json是否爲空？

Question

我想檢查結果的JSON爲空或不是..我用這個代碼

- (NSString *)likesCount { 
    if ([facebook valueForKey:@"likes"] == [NSNull null]) { 

     return @""; 
    } 
    else { 

    return [facebook valueForKey:@"likes"]; 

    } 
} 

likes = 1;如果它存在並且爲空"like"在輸出中不可見但是如果它不存在那麼它將返回(null) ..我使用上面的代碼但它不起作用。

我打印喜歡的這個值的UITableViewCell

UILabel *commentLike = [[UILabel alloc] initWithFrame:CGRectMake(200, 70, 100, 20)]; 
commentLike.font = [UIFont fontWithName:@"Arial" size:10.0]; 

NSString *commentLikeString = [NSString stringWithFormat:@"%@ ",[(Facebook *)[tableArray objectAtIndex:indexPath.row]likesCount]]; 
    commentLike.text = [NSString stringWithFormat:@"%@ Person"]; 
    [cell.contentView addSubview:commentLike]; 

感謝

Answer 1

使用該類別上的NSDictionary，代碼就會乾淨得多：

TouchJSON, dealing with NSNull

Answer 2

試試這個代碼

- (NSString *)likesCount { 
    if ([[facebook valueForKey:@"likes"] isEqualToString:@"(null)"] || [facebook valueForKey:@"likes"] == nil) { 

     return @""; 
    } 
    else { 

    return [facebook valueForKey:@"likes"]; 

    } 
}