Iphone: UIAlert with message box

 UIAlertView * alert = [[UIAlertView alloc] initWithTitle:@"Hello Cogi User!" message:@"Please enter phone number of this device:" delegate:self cancelButtonTitle:@"Continue" otherButtonTitles:nil];

    alert.alertViewStyle = UIAlertViewStylePlainTextInput;

    UITextField * alertTextField = [alert textFieldAtIndex:0];

    alertTextField.keyboardType = UIKeyboardTypeNumberPad;

    alertTextField.placeholder = @"Enter Phone Number";

    [alert show];

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- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {

    NSString* detailString =[alertView textFieldAtIndex:0].text;

   

    

   

    if (buttonIndex == 0){

        

     // do your work

        

        return; //If cancel or 0 length string the string doesn't matter

    }

   

}