Question

我第一次使用UIAlertController。我需要提示用户输入。无论如何，以下就是我所拥有的。

- (void)showAlert {
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Hello!" message:@"Type something.") preferredStyle:UIAlertControllerStyleAlert];
    UIAlertAction *noButton = [UIAlertAction actionWithTitle:@"Cancel") style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {

    }];
    UIAlertAction *yesButton = [UIAlertAction actionWithTitle:@"Enter") style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
        //NSString *input = alert.textFields[0].text;
        //NSLog(@"input was '%@'", input);
        UITextField *textField = alert.textFields[0];
        NSLog(@"%@",textField.text); // <====== It's not returned

    }];
    [alert addTextFieldWithConfigurationHandler:^(UITextField *textField) {
        [textField addTarget:self action:@selector(alertTextFieldDidChange:) forControlEvents:UIControlEventEditingChanged];
        [yesButton setEnabled:NO];
    }];
    [alert addAction:noButton];
    [alert addAction:yesButton];
    [self presentViewController:alert animated:YES completion:nil];
}

- (void)alertTextFieldDidChange:(UITextField *)sender {
    UIAlertController *alertController = (UIAlertController *)self.presentedViewController;
    if (alertController) {
        UITextField *textfield = alertController.textFields.firstObject;
        UIAlertAction *okAction = alertController.actions.lastObject;
        okAction.enabled = [self validateName2:textfield.text:5]; // function for validating user input
    }
}

出于某种原因，当用户点击“是”时，应用程序不会返回用户输入。事实上，Xcode破坏了'NSString * input = alert.textFields [0] .text中的'text'。奇怪的是UIAlertView没有返回用户输入。这就是为什么我切换到UIAlertController。

- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex {
    if ([alertView tag] == 101) {
        if (buttonIndex == 1) {
            NSString *username = [[alertView textFieldAtIndex:0] text];
            NSLog(@"%@",username); // <====== It's never returned.
        }
    }
}

无论如何，我想知道我对UIAlertController做错了什么？

Muchos thankos

P.S。我正在使用Xcode 6.4（6E35b）。此问题可能是由Xcode引起的。如果我使用iPad2模拟器调试代码，它实际上将返回用户输入，而如果我使用iPhone4S模拟器则不会。

Answer 1

将此用于alertcontroller中的textField

__block typeof(self) weakSelf = self;
UIAlertController *alertController;

alertController = [UIAlertController alertControllerWithTitle:title
                                     message:message
                                     preferredStyle:UIAlertControllerStyleAlert];


[alertController addTextFieldWithConfigurationHandler:^(UITextField *textField)
 {
     textField.tag = 1001;
     textField.delegate = weakSelf;
     textField.placeholder = @"";

     [textField addTarget:weakSelf action:@selector(alertTextFieldDidChange:)
         forControlEvents:UIControlEventEditingChanged];
 }];


//OK Button
UIAlertAction *okAction = [UIAlertAction
                           actionWithTitle:@"OK"
                           style:UIAlertActionStyleDefault
                           handler:^(UIAlertAction *action)
                           {
                               UITextField *textField = alertController.textFields.firstObject;

                               // Do stuff here
                           }];



[alertController addAction:okAction];
[self presentViewController:alertController animated:YES completion:nil];

- (void)alertTextFieldDidChange:(UITextField *)sender
 {
   alertController = (UIAlertController *)self.presentedViewController;
   if (alertController)
   {
     UITextField *textField = alertController.textFields.firstObject;
     UIAlertAction *okAction = alertController.actions.lastObject;

     okAction.enabled = textField.text.length > 0; // condition to enable button
   }
}

 #pragma mark - UITextField delegate methods

-(BOOL)textFieldShouldReturn:(UITextField *)textField{

    [textField resignFirstResponder];
    return YES;
 }

Answer 2

我建议使用UITextFieldDelegate来处理textField！

如果textField.delegate = self的长度为＆gt;，请设置- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string，然后使用alertTextFieldDidChange方法执行replacementString中的操作0

您为UITextField提供了委托方法，因此您不必自己创建选择器，我建议您充分利用它们！

如果您想了解更多信息，请参阅以下文档！ https://developer.apple.com/library/ios/documentation/UIKit/Reference/UITextFieldDelegate_Protocol/

UIAlertController不返回用户输入

2 个答案: