ios - 带有 UITextfield 的 UIAlertController 不显示标题和消息

Question

请帮我解决以下问题。

UIAlertController *alertController = [UIAlertController  alertControllerWithTitle:@"Check"  message:@"What was the value collected?"  preferredStyle:UIAlertControllerStyleAlert];
[alertController addTextFieldWithConfigurationHandler:^(UITextField *textField)
{
    textField.keyboardType = UIKeyboardTypeNumberPad;
    textField.placeholder = @"What was the value collected?";
}];

[alertController addAction:[UIAlertAction actionWithTitle:@"Submit" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) 
{                  
    UITextField *txtValue = alertController.textFields.firstObject;                    
    toCollect = [txtValue.text floatValue];
}]];
[self presentViewController:alertController animated:YES completion:nil];

我使用了上面的代码，但它在下面的屏幕截图中显示了结果。无法显示标题和消息

提前致谢!

Answer 1

这是创建用于显示消息和标题的 UIAlertController 的代码。

UIAlertController *alertController = [UIAlertController
                                      alertControllerWithTitle:@"Alert Controller"
                                      message:@"Alert Message"
                                      preferredStyle:UIAlertControllerStyleAlert];

UIViewController *viewController = [[UIViewController alloc]init];
[viewController.view setBackgroundColor:[UIColor blueColor]];

UILabel *lbl = [[UILabel alloc]initWithFrame:CGRectMake(10, 8, 250, 30)];
lbl.text = @"This is a label";
lbl.textAlignment = NSTextAlignmentCenter;
lbl.textColor = [UIColor whiteColor];
[viewController.view addSubview:lbl];

UITextField *tf = [[UITextField alloc]initWithFrame:CGRectMake(10, 35, 250, 30)];
tf.borderStyle = UITextBorderStyleRoundedRect;
tf.placeholder = @"Enter your name";
[viewController.view addSubview:tf];

[alertController setValue:viewController forKey:@"contentViewController"];

UIAlertAction *cancelAction = [UIAlertAction
                               actionWithTitle:@"Cancel"
                               style:UIAlertActionStyleCancel
                               handler:^(UIAlertAction *action)
                               {
                                   NSLog(@"Cancel action");
                               }];

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

                               NSLog(@"Text Value : %@",tf.text);
                           }];

[alertController addAction:cancelAction];
[alertController addAction:okAction];

dispatch_async(dispatch_get_main_queue(), ^{
    [self presentViewController:alertController animated:YES completion:nil];
});

对于swift，你可以像下面的代码一样做同样的事情:

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


let cancelAction = UIAlertAction(
    title: "Cancel",
    style: UIAlertActionStyle.Destructive) { (action) in

}

let confirmAction = UIAlertAction(
    title: "OK", style: UIAlertActionStyle.Default) { (action) in

}

alert.addAction(confirmAction)
alert.addAction(cancelAction)

let VC = UIViewController()
VC.view.backgroundColor = UIColor.blackColor()


let lbl =  UILabel()
lbl.frame =  CGRectMake(10, 8, 250, 30)
lbl.text = "this is a label"
lbl.textAlignment = NSTextAlignment.Center
lbl.textColor = UIColor.whiteColor()
VC.view .addSubview(lbl)


let txt = UITextField()
txt.frame =  CGRectMake(10, 35, 250, 30)
txt.borderStyle = UITextBorderStyle.RoundedRect
txt.placeholder = "enter text"
VC.view .addSubview(txt)


alert.setValue(VC, forKey: "contentViewController")

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

从 Github 下载演示:https://github.com/nitingohel/NGAlertViewController-Swift2.0