ios - UIAlertViewController 添加文本字段委托(delegate)

Question

I have implemented textfield in UIAlertViewController but I want implement delegate methods to that textfields.

`UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Total Value"  message:@""  preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* ok = [UIAlertAction actionWithTitle:@"YES" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action)
{
     [alert dismissViewControllerAnimated:YES completion:nil];
}];
[ok setEnabled:NO];
[alert addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField)
 {
     textField.placeholder = @"TotalValue";
     textField.enabled = YES;
     [[alert textFields][0] delegate];
     [NSNotificationCenter.defaultCenter addObserverForName:UITextFieldTextDidChangeNotification object:textField queue:NSOperationQueue.mainQueue usingBlock:^(NSNotification * _Nonnull note)
      {
          textField.text.length >0 ? [ok setEnabled:YES]: [ok setEnabled:NO];
      }];
     [NSNotificationCenter.defaultCenter addObserverForName:UITextFieldTextDidEndEditingNotification object:textField queue:NSOperationQueue.mainQueue usingBlock:^(NSNotification * _Nonnull note)
      {
          [self updateTotalValue:textField.text];
      }];
 }];
[alert addAction:ok];
UIAlertAction* cancel = [UIAlertAction actionWithTitle:@"NO" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action)
                         {
                             [alert dismissViewControllerAnimated:YES completion:nil];
                         }];
[alert addAction:cancel];
[self.navigationController presentViewController:alert animated:YES completion:nil];`UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Total Value"  message:@""  preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* ok = [UIAlertAction actionWithTitle:@"YES" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action)
{
     [alert dismissViewControllerAnimated:YES completion:nil];
}];
[ok setEnabled:NO];
[alert addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField)
 {
     textField.placeholder = @"TotalValue";
     textField.enabled = YES;
     [[alert textFields][0] delegate];
     [NSNotificationCenter.defaultCenter addObserverForName:UITextFieldTextDidChangeNotification object:textField queue:NSOperationQueue.mainQueue usingBlock:^(NSNotification * _Nonnull note)
      {
          textField.text.length >0 ? [ok setEnabled:YES]: [ok setEnabled:NO];
      }];
     [NSNotificationCenter.defaultCenter addObserverForName:UITextFieldTextDidEndEditingNotification object:textField queue:NSOperationQueue.mainQueue usingBlock:^(NSNotification * _Nonnull note)
      {
          [self updateTotalValue:textField.text];
      }];
 }];
[alert addAction:ok];
UIAlertAction* cancel = [UIAlertAction actionWithTitle:@"NO" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action)
                         {
                             [alert dismissViewControllerAnimated:YES completion:nil];
                         }];
[alert addAction:cancel];
[self.navigationController presentViewController:alert animated:YES completion:nil];

ERoor : Assigning to 'id _Nullable' from incompatible type 'ApprovalDetailsViewController *const __strong'

在 addtextfieldconfiguration 中，我想执行我的委托(delegate)方法，但它会出现一些错误 请谁能举个例子。

Answer 1

你可以像下面这样实现-

-(void)showAlert {

    UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Total Value"  message:@""  preferredStyle:UIAlertControllerStyleAlert];
    UIAlertAction* ok = [UIAlertAction actionWithTitle:@"YES" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action)
                         {
                             [alert dismissViewControllerAnimated:YES completion:nil];
                         }];
    [ok setEnabled:NO];

    __weak typeof(self) weakSelf = self;

    [alert addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField)
     {
         __strong typeof(self) strongSelf = weakSelf;

         textField.placeholder = @"TotalValue";
         textField.enabled = YES;
         textField.delegate = strongSelf;
         [NSNotificationCenter.defaultCenter addObserverForName:UITextFieldTextDidChangeNotification object:textField queue:NSOperationQueue.mainQueue usingBlock:^(NSNotification * _Nonnull note)
          {
              textField.text.length >0 ? [ok setEnabled:YES]: [ok setEnabled:NO];
          }];
         [NSNotificationCenter.defaultCenter addObserverForName:UITextFieldTextDidEndEditingNotification object:textField queue:NSOperationQueue.mainQueue usingBlock:^(NSNotification * _Nonnull note)
          {
              [strongSelf upadteTotalValue:textField.text];
          }];
     }];
    [alert addAction:ok];




    UIAlertAction* cancel = [UIAlertAction actionWithTitle:@"NO" style:UIAlertActionStyleDefault handler:^(UIAlertAction * action)
                             {
                                 [alert dismissViewControllerAnimated:YES completion:nil];
                             }];
    [alert addAction:cancel];


    [self.navigationController presentViewController:alert animated:YES completion:nil];
}
-(void)upadteTotalValue:(NSString *)text {
    NSLog(@"%s",__FUNCTION__);
}

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    NSLog(@"%s",__FUNCTION__);
    return YES;
}

-(void)textFieldDidEndEditing:(UITextField *)textField {
    NSLog(@"%s",__FUNCTION__);

}