iphone - 如何比较自定义 UITableViewCel 中的标签是否为空？

Question

我有一个带有 2 个日期标签的自定义 TableViewCell，当 coreData 未保存任何内容时，我的日期标签应该选择一个示例日期。但是当设置日期时，我想在我的标签中显示它。我用下面的代码尝试过，但无法正常工作。

你能帮我吗？

这是我的代码:

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


    ProduktTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {
        cell = [[ProduktTableViewCell alloc] initWithFrame:CGRectZero];
    }
    NSManagedObject *managedObject = [self.fetchedResultsController objectAtIndexPath:indexPath];


    cell.produktnameLabel.text = [managedObject valueForKey:@"produktname"]; 
    NSLog(@"%@",cell.vonDatumLabel.text);

    if ([cell.vonDatumLabel.text length] > 1){
        cell.vonDatumLabel.text = [managedObject valueForKey:@"vondatum"];
        cell.bisDatumLabel.text = [managedObject valueForKey:@"bisdatum"]; 

    }else {
        cell.vonDatumLabel.text = dateString;
        cell.bisDatumLabel.text = dateString1;
    }



        cell.datumButton.tag = indexPath.row;
    cell.warenkorbButton.tag = indexPath.row;
    cell.menge.tag = indexPath.row + 437812;
    cell.mengeLabel.text = [managedObject valueForKey:@"mengelabel"];




    NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
    NSLocale *german = [[NSLocale alloc] initWithLocaleIdentifier:@"de_DE"];
    [formatter setLocale:german];
    [formatter setNumberStyle:NSNumberFormatterCurrencyStyle];
    [formatter setMinimumFractionDigits:2];
    [formatter setMaximumFractionDigits:2];


    NSNumber *firstNumber = [managedObject valueForKey:@"preis"];

    cell.preisLabel.text = [formatter stringFromNumber:firstNumber];



    return cell;
}

Answer 1

Make if condition like this 

if ([[managedObject valueForKey:@"produktname"] length] > 1){
        cell.vonDatumLabel.text = [managedObject valueForKey:@"vondatum"];
        cell.bisDatumLabel.text = [managedObject valueForKey:@"bisdatum"]; 

    }else {
        cell.vonDatumLabel.text = dateString;
        cell.bisDatumLabel.text = dateString1;
    }

Surely this will help ful