ios - View 更改后TableView不显示数据

Question

我有一个问题。目前我正在完善我的应用程序并对其进行调试等等。奇怪的事情发生了。它的工作原理如下:用户输入数据并访问 TableView，然后显示数据。简单的。但一旦他切换到另一个 View ，然后再回到TableView，数据就消失了!奇怪的是，以前没有发生过这种情况。 (我重做了一些代码行，也许我在不知不觉中改变了一些东西)。我预感到它可能是什么，但这会很奇怪，因为它以前有效。我认为问题出在buttonTag行:

      - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

if (cell == nil) {
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}

  // cell.image = selectedImage;
cell.textLabel.font = [UIFont fontWithName:@"Georgia" size:14.0];

if (buttonTag == 9001) {    
cell.textLabel.text = [NSString stringWithFormat:@"%@  %@ %@,  %@.", [self.userData objectAtIndex:0], [self.userData objectAtIndex:1], [self.userData objectAtIndex:2], [self.userData objectAtIndex:3]];
    }
if (buttonTag == 9002) {    
    cell.textLabel.text = [NSString stringWithFormat:@"%@ %@ %@, %@.", [self.userData objectAtIndex:0], [self.userData objectAtIndex:1], [self.userData objectAtIndex:2], [self.userData objectAtIndex:3]];
}
if (buttonTag == 9003) {    
    cell.textLabel.text = [NSString stringWithFormat:@"%@  %@ %@,%@.", [self.userData objectAtIndex:0], [self.userData objectAtIndex:1], [self.userData objectAtIndex:2], [self.userData objectAtIndex:3]];
}


return cell;

}

因为他只是在按下特定按钮时显示数据。如果您在未按这些按钮之一(例如从选项卡栏)的情况下更改为 TableView，则它不会显示任何内容。我现在的问题是:如何告诉 TableView 维护最后按下的按钮中的数据？ (我在想 NSUserDefaults？)

这是另一个 ViewController，您可以从其中访问 TableView:

  - (IBAction)savePressed:(id)sender

{
if (buttonTag == 9001) {
     button.tag = 9001;
NSUserDefaults *savetext = [NSUserDefaults standardUserDefaults];
[savetext setObject:Antwort.text forKey:@"hallo"];
[savetext setObject:Antwort2.text forKey:@"hallo2"];
[savetext setObject:Antwort3.text forKey:@"hallo3"];
UIButton *buttonPressed = (UIButton *)sender;
TV *second =[[TV alloc] initWithNibName:nil bundle:nil];
second.buttonTag  = buttonPressed.tag; 
    [self.navigationController pushViewController:second animated:YES];

}
if (buttonTag == 9002) {
     button.tag = 9002;
    NSUserDefaults *savetext = [NSUserDefaults standardUserDefaults];
    [savetext setObject:Antwort.text forKey:@"hallo"];
    [savetext setObject:Antwort2.text forKey:@"hallo2"];
    [savetext setObject:Antwort3.text forKey:@"hallo3"];
    UIButton *buttonPressed = (UIButton *)sender;
    TV *second =[[TV alloc] initWithNibName:nil bundle:nil];
    second.buttonTag  = buttonPressed.tag; 
  [self.navigationController pushViewController:second animated:YES];

}
if (buttonTag == 9003) {
    button.tag = 9003;
    NSUserDefaults *savetext = [NSUserDefaults standardUserDefaults];
    [savetext setObject:Antwort.text forKey:@"hallo"];
    [savetext setObject:Antwort2.text forKey:@"hallo2"];
    [savetext setObject:Antwort3.text forKey:@"hallo3"];
    UIButton *buttonPressed = (UIButton *)sender;
    TV *second =[[TV alloc] initWithNibName:nil bundle:nil];
    second.buttonTag  = buttonPressed.tag; 
[self.navigationController pushViewController:second animated:YES];

}

}

Answer 1

如果数据被读取并保存在 NSUSerDefaults 中，请尝试

[savetext synchronize] 

在推送到新 View 之前。