UIAlertController Does Not Return User Input - ios

Question

I'm using UIAlertController for the first time. I need to prompt the user for an input. Anyway, the following is what I have.
- (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
}
}
For some reason, when the user tap Yes, the application doesn't return user input. In fact, Xcode dashes 'text' as in 'NSString *input = alert.textFields[0].text. A strange thing is that UIAlertView doesn't return user input. That's why I've switched to 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.
}
}
}
Anyway, I wonder what I'm doing wrong with UIAlertController?
Muchos thankos
p.s. I'm using Xcode 6.4 (6E35b). This issue may be caused by Xcode. If I debug the code with the iPad2 simulator, it'll actually return user input while it doesn't if I use the iPhone4S simulator.

Answer 1

Use this for textField in alertcontroller
__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

I would recommend using UITextFieldDelegate to handle the textField!
Set textField.delegate = self and then use the - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string method to do what you do in alertTextFieldDidChange if the replacementString has a length of > 0.
You are provided with delegate methods for UITextField so you don't have to create the selectors yourself, I recommend you use them to their fullest!
Here are the docs in case you want to know more! https://developer.apple.com/library/ios/documentation/UIKit/Reference/UITextFieldDelegate_Protocol/