Bug / Error with multiple UIAlertViews - ios

Question

I'm getting a really weird error when woking with UIAlertViews. Been pulling my hair out over this, please help me out!
The error occurs when I press "Create!" in the alert1 alert and checkUsernameExists returns true and then I press "K." in alert3.
Code
-(void) newProfile:(id)sender {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"New Profile"
message:nil
delegate:self
cancelButtonTitle:#"Create!"
otherButtonTitles:nil];
alert.alertViewStyle = UIAlertViewStyleLoginAndPasswordInput;
UITextField *username = [alert textFieldAtIndex:0];
username.keyboardType = UIKeyboardTypeDefault;
username.placeholder = #"Desired Username";
UITextField *password = [alert textFieldAtIndex:1];
password.keyboardType = UIKeyboardTypeDefault;
password.placeholder = #"Desired Password";
[alert1 show];
}
- (void)alertView:(UIAlertView *)alert clickedButtonAtIndex:(NSInteger)buttonIndex {
NSString *title = [alert title];
UITextField *username = [alert textFieldAtIndex:0];
UITextField *passwrod = [alert textFieldAtIndex:1];
if ([title isEqualToString:#"New Profile"]) {
if ([self checkUsernameExists:username.text] == false) {
// Create new account
}
else {
[self errorPop:#"New Profile"];
}
}
}
-(void) errorPop:(NSString*)who {
if ([who isEqualToString:#"New Profile"]) {
UIAlertView *alert3 = [[UIAlertView alloc] initWithTitle:#"OH NOOOOO"
message:#"Username is already taken please try another one."
delegate:self
cancelButtonTitle:#"K."
otherButtonTitles:nil];
[alert3 show];
}
}
Logs
2014-07-30 19:57:49.594 App[6532:a0b] * Terminating app due to
uncaught exception 'NSInvalidArgumentException', reason:
'textFieldIndex (0) is outside of the bounds of the array of text
fields'

Answer 1

The first alert view does not contain text fields, so when you request the first or second text field in -clickedButtonAtIndex:, you get an out of bounds exception.
You should distinguish which for which alert view you are receiving the callback. Try storing the alert views in a property upon creation, and then check for their identity in the callback before trying to access text fields.

Answer 2

Just set the delegate to nil for alert3 so it will not go under method "- (void)alertView:(UIAlertView *)alert clickedButtonAtIndex:(NSInteger)buttonIndex".
Actually alert3 doesn't contain tetxfield and you have set delegate for this alert too so it is going to delegate method where they are trying to get UItextField but they don't have that's why it is crashing.