UIAlertController获取文本

Question

我正在尝试从UIAlertController文本字段中获取文本。谁能告诉我我做错了什么，因为它不工作。我得到的回报是零。

- (IBAction)btnMakeRec {

        UIAlertController *alert= [UIAlertController
                                   alertControllerWithTitle:@"Recipe Name?"
                                   message:@""
                                   preferredStyle:UIAlertControllerStyleAlert];

        UIAlertAction* ok = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault
                                                   handler:^(UIAlertAction * action){


                                               UITextField *temp = alert.textFields.firstObject;

                                               RecipeDesc.text = temp.text;
                                               // HERE temp is Nil


                                               RDescription = [[NSString alloc ] initWithFormat:@"%@", RecipeDesc.text];


                                                   }];

        UIAlertAction* cancel = [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleDefault
                                                       handler:^(UIAlertAction * action) {

                                                         //  NSLog(@"cancel btn");

                                                           [alert dismissViewControllerAnimated:YES completion:nil];

                                                       }];

        [alert addAction:ok];
        [alert addAction:cancel];

        [alert addTextFieldWithConfigurationHandler:^(UITextField *textField) {
            textField.placeholder = @"Enter the name of the recipe";
            textField.keyboardType = UIKeyboardTypeDefault;
        }];

        [self presentViewController:alert animated:YES completion:nil];

    }

}

Answer 1

这是“干净复制/粘贴”的版本：

Swift 3+:

let alert = UIAlertController(title: "Alert Title",
                              message: "Alert message",
                              preferredStyle: .alert)

let ok = UIAlertAction(title: "OK",
                       style: .default) { (action: UIAlertAction) in
                        
                        if let text = alert.textFields?.first?.text {
                            
                            print("And the text is... \(text)")
                            
                        }
                        
                        
}

let cancel = UIAlertAction(title: "Cancel",
                           style: .cancel,
                           handler: nil)

alert.addTextField { (textField: UITextField) in
    
    textField.placeholder = "Text here"
    
}

alert.addAction(ok)
alert.addAction(cancel)

self.present(alert, animated: true, completion: nil)

Swift 2:

let alert = UIAlertController(title: "Alert Title",
                              message: "Alert message",
                              preferredStyle: UIAlertControllerStyle.Alert)

let ok = UIAlertAction(title: "OK",
                       style: UIAlertActionStyle.Default) { (action: UIAlertAction) in
                        
                        if let alertTextField = alert.textFields?.first where alertTextField.text != nil {
                            
                            print("And the text is... \(alertTextField.text!)!")
                            
                        }
                        
                        
}

let cancel = UIAlertAction(title: "Cancel",
                           style: UIAlertActionStyle.Cancel,
                           handler: nil)

alert.addTextFieldWithConfigurationHandler { (textField: UITextField) in
    
    textField.placeholder = "Text here"
    
}

alert.addAction(ok)
alert.addAction(cancel)

self.presentViewController(alert, animated: true, completion: nil)

目标C:

UIAlertController *alert = [UIAlertController
                           alertControllerWithTitle: @"Alert Title"
                           message: @"Alert message"
                           preferredStyle:UIAlertControllerStyleAlert];

UIAlertAction *ok = [UIAlertAction actionWithTitle: @"OK" style: UIAlertActionStyleDefault
                                           handler:^(UIAlertAction *action){
                                               
                                               
                                               UITextField *alertTextField = alert.textFields.firstObject;
                                               
                                               NSLog(@"And the text is... %@!", alertTextField.text);
                                               
                                           }];

UIAlertAction *cancel = [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel
                                               handler: nil];


[alert addTextFieldWithConfigurationHandler:^(UITextField *textField) {

    textField.placeholder = @"Text here";

}];

[alert addAction:ok];
[alert addAction:cancel];

[self presentViewController:alert animated:YES completion:nil];

上一个答案：

编辑：-请注意:目前，原始问题似乎是按原样工作。

澄清一下：

UIAlertController实例应该在调用textField之后将textFields保存在它的addTextFieldWithConfigurationHandler数组中。

UIAlertController *alertController = ...// Create alert

// Assuming you called 'addTextFieldWithConfigurationHandler' on 'alertController'

UIAlertAction *action = [UIAlertAction actionWithTitle: ... handler:^(UIAlertAction * action) {
    
    // alertController.textFields should hold the alert's text fields.
}

如果由于某种原因不是，请提供更多的信息(因为这个问题仍然受到关注)。它似乎(通过一些评论)，一些人对此有一些问题，但没有提供信息，除了‘它不工作’。

原始答案：

您的代码看起来很好，应该可以工作。

另一种方法是在UIAlertController *alert=...之前定义UITextField

UITextField *myTf;

从addTextFieldWithConfigurationHandler传递textField

[alert addTextFieldWithConfigurationHandler:^(UITextField *textField) {
            textField.placeholder = @"Enter the name of the recipe";
            textField.keyboardType = UIKeyboardTypeDefault;

            myTf = textField;
        }];

然后，在：

UIAlertAction* ok = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault
                                               handler:^(UIAlertAction * action){...
//UITextField *temp = alert.textFields.firstObject;

// Get the text from your textField
NSString *temp = myTf.text;

-- 编辑

原始poster的代码现在可以像一样工作(在Xcode7，iOS 9下测试)。可能是以前版本中的错误。可能是因为在以前的版本中，textField是由弱引用持有的，除非另一个强指针持有它，否则会被释放。