`UIAlertController` is not triggered in NSNotification response - objective-c

Question

This is my AlertView code :
- (void)initializeAlertControllerForOneButtonWithTitle:(NSString *)title withMessage:(NSString *)msg withYesButtonTitle:(NSString *)yesButtonTitle withYesButtonAction:(id)yesButtonAction
{
UIAlertController * alert = [UIAlertController
alertControllerWithTitle:title
message:msg
preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* yesBtn = [UIAlertAction
actionWithTitle:yesButtonTitle
style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action) {
if (self.activityIndicator.animating) {
[self.activityIndicator stopAnimating];
}
if ([title isEqualToString:#"Wrong Password!"]) {
self.editTextField.text = #"";
[self.editTextField becomeFirstResponder];
}
}];
[alert addAction:yesBtn];
[self presentViewController:alert animated:YES completion:nil];
}
I am trying to fire this alert in my NSNotificatoin Response method. My Notification Response code :
- (void)receiveSMSVerificationResponse:(NSNotification *)notification
{
SMSVerificationDigitClassModel *smsVerificationDigitClassModel = [[SMSVerificationDigitClassModel alloc] init];
smsVerificationDigitClassModel = [notification object];
if (smsVerificationDigitClassModel.viewControllerName == ViewControllerNameProfileInfoEditViewController) {
if ([self alreadyRegisteredPhoneNumber:smsVerificationDigitClassModel.phoneNumber] == YES) {
NSLog(#"jogajog");
[self initializeAlertControllerForOneButtonWithTitle:#"Already Registered!" withMessage:kAlreadyRegisteredPhoneNumberMSGForChangePhoneNumber withYesButtonTitle:#"Ok" withYesButtonAction:nil];
} else {
if ([AdditionalClasses internetConnectionCheck] == YES) {
self.userModelClass.phone_number = smsVerificationDigitClassModel.phoneNumber;
[self updateUserModel:self.userModelClass];
} else {
[self noInternetConnectionAlert];
}
}
//Check if that phone number is already used
// udate phone numner in server
// update phone number in core data
//[self goToSignUpViewControllerWithPhoneNumber:smsVerificationDigitClassModel.phoneNumber];
}
}
I check it from break point, this line [self initializeAlertControllerForOneButtonWithTitle:#"Already Registered!" withMessage:kAlreadyRegisteredPhoneNumberMSGForChangePhoneNumber withYesButtonTitle:#"Ok" withYesButtonAction:nil]; is actually calling, but the alert view is not popping up. It says:
"Warning: Attempt to present on whose view is not in the window hierarchy!"
I have tried to add notification observer methods :
- (void)addNotificationObserver
{
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(receiveUserModelResponse:) name:#"sendUpdateRequestToServerForPhoneNumberWithUserModel" object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(receiveSMSVerificationResponse:) name:#"SMSVerificationForPhoneNumber" object:nil];
}
In viewDidLoad, viewDidAppear & in viewWillAppear and removeObserver in dealloc,
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self name:#"sendUpdateRequestToServerForPhoneNumberWithUserModel" object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self name:#"SMSVerificationForPhoneNumber" object:nil];
}
but it is not showing at all. So, how do I change my window hierarchy! in this viewController. If you understand, please reply back. A lot of thanks in advance.

Answer 1

Call the initializeAlertControllerForOneButtonWithTitle method inside a main queue dispatch queue block.
All UI operation should be on main threat.
dispatch_async(dispatch_get_main_queue(), ^{
[self initializeAlertControllerForOneButtonWithTitle:#"Already Registered!" withMessage:kAlreadyRegisteredPhoneNumberMSGForChangePhoneNumber withYesButtonTitle:#"Ok" withYesButtonAction:nil];
});