How do I validate TextFields in an UIAlertController?

Question

Can anyone tell me how to validate UITextFields inside of a UIAlertController?

I need it to prevent the user from clicking \"Save\" unless

Answer 1

You can use below code to validate TextFields in an UIAlertController :-

Step 1:

Declare "email_TF" to your viewcontroller.h 

for example: 
    @property(strong,nonatomic)UITextField *email_TF;

Step 2:

UIAlertController *alert= [UIAlertController alertControllerWithTitle:@"Forgot Password?" message:nil preferredStyle:UIAlertControllerStyleAlert];
[alert addTextFieldWithConfigurationHandler: ^(UITextField *textField){
    textField.placeholder= @"Enter Your Valid Email";
    textField.autocorrectionType= UITextAutocorrectionTypeYes;
    textField.keyboardType= UIKeyboardTypeEmailAddress;

    email_TF= textField;
}];

Step 3:

UIAlertAction *noButton= [UIAlertAction actionWithTitle:@"No, thanks" style:UIAlertActionStyleDestructive handler:^(UIAlertAction *action){
    //Handel no, thanks button
}];
[alert addAction:noButton];

UIAlertAction *yesButton= [UIAlertAction actionWithTitle:@"Yes, please" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action){
    //Handel your yes please button action here
    NSLog(@"%@", email_TF.text);

    if(email_TF.text.length>0){//

        NSString *emailString= email_TF.text;
        NSString *emailReg= @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
        NSPredicate *emailTest= [NSPredicate predicateWithFormat:@"SELF MATCHES %@",emailReg];

        if(([emailTest evaluateWithObject:emailString]!=YES) || [emailString isEqualToString:@""]){

            UIAlertView *loginalert= [[UIAlertView alloc] initWithTitle:@"Forgot Password !" message:@"\nPlease enter valid Email (example@example.com format) ." delegate:self cancelButtonTitle:@"Ok" otherButtonTitles: nil];
            [loginalert show];

        }else{

            NSLog(@"your TextField successfully validated");

        }
    }else{

        UIAlertView *alert= [[UIAlertView alloc] initWithTitle:@"Forgot Password !" message:@"\nPlease Enter Your Email..." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
        [alert show];

    }

}];

[alert addAction:yesButton];

Step 4:

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