forgot password/username Xcode - ios

Question

I am building login/signup pages and it's work so perfectly.
But I just want to know how I can add a label or a button for the "Forgot my password or username" on the login page.
I'd like to have a pop up message or an alert that allows the user to enter their Email
so in case their Email doesn't exist in the database there will pop a message that says, that this email is not correct or something
in case the email already exists in the database I want to send the username and a new password to the user.
Please note that I am using parse.
Thank you,

Answer 1

First display an alert view with type UIAlertViewStylePlainTextInput
UIAlertView * forgotPassword=[[UIAlertView alloc] initWithTitle:#"Forgot Password" message:#"Please enter your email id" delegate:self cancelButtonTitle:#"Cancel" otherButtonTitles:#"Ok", nil];
forgotPassword.alertViewStyle=UIAlertViewStylePlainTextInput;
[forgotPassword textFieldAtIndex:0].delegate=self;
[forgotPassword show];
and in your alert view delegate
if(buttonIndex ==1){
NSLog(#"ok button clicked in forgot password alert view");
NSString *femailId=[alertView textFieldAtIndex:0].text;
if ([femailId isEqualToString:#""]) {
UIAlertView *display;
display=[[UIAlertView alloc] initWithTitle:#"Email" message:#"Please enter password for resetting password" delegate:nil cancelButtonTitle:#"Ok" otherButtonTitles: nil];
[display show];
}else{
[PFUser requestPasswordResetForEmailInBackground:femailId block:^(BOOL succeeded, NSError *error) {
UIAlertView *display;
if(succeeded){
display=[[UIAlertView alloc] initWithTitle:#"Password email" message:#"Please check your email for resetting the password" delegate:nil cancelButtonTitle:#"Ok" otherButtonTitles: nil];
}else{
display=[[UIAlertView alloc] initWithTitle:#"Email" message:#"Email doesn't exists in our database" delegate:nil cancelButtonTitle:#"Cancel" otherButtonTitles: nil];
}
[display show];
}];
}