How to move to 2nd ViewController after data validation complete - ios

Question

I'm creating a small app which verifies username and password from plist and shows user profile in other ViewController or (next screen).
I added a Login Button which validates username and password from user input with data stored in Plist(property list).
I also added a condition for show alert message when user entered wrong password or logged in successfully.
I created an another ViewController and connects with main ViewController via Login button.
my problem is when i clicked LOGIN button, it automatically moves to next view controller without checking username password and also not shows alert.
how to go next ViewController after validation completes and alert view done.
I need code in Objective-C
- (IBAction)submitButton:(UIButton *)sender {
NSDictionary *dict = [[NSDictionary alloc] initWithContentsOfFile:[[NSBundle mainBundle]pathForResource:#"profileDetails" ofType:#"plist"]];
NSString *usernameentered = dict[#"user"][#"username"];
NSString *passwordentered = dict[#"user"][#"password"];
if ([self.username.text isEqualToString:usernameentered] && [self.password.text isEqualToString:passwordentered]) {
NSLog(#"login sucessfull");
UIAlertController* alert = [UIAlertController alertControllerWithTitle:#"Attention"
message:#"LOGIN SUCCESS"
preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* defaultAction = [UIAlertAction actionWithTitle:#"OKAY" style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action) {}];
[alert addAction:defaultAction];
[self presentViewController:alert animated:YES completion:nil];
}else if ([self.username.text isEqual:#""] && [self.password.text isEqual:#""]) { UIAlertController* alert = [UIAlertController alertControllerWithTitle:#"Attention"
message:#"PLEASE ENTER Valid EMAIL AND PASSWORD"
preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* defaultAction = [UIAlertAction actionWithTitle:#"Okay ! Got it" style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action) {}];
[alert addAction:defaultAction];
[self presentViewController:alert animated:YES completion:nil];
}
}

Answer 1

I think you have use 'show' segue in tap of login button tap.you need to use custom segue for it. You can setup custom segue as below.
Step 1:
Give custom segue to current controller to target controll. You can also see in below image.
Step 2
- Give any unique identifier to segue. You can also see in below image.
Then use below code for redirection when credential is valid.
[self performSegueWithIdentifier:#"NextVC" sender:self];

Answer 2

"i created an another view controller and connects with main view controller via Login button"
If you're using segue to navigate then you should write code inside prepareForSegue or shouldPerformSegueWithIdentifier method. Otherwise you can navigate to ViewController through code inside submit button action.
Try writing this code inside shouldPerformSegueWithIdentifier method, it should work

Answer 3

- (IBAction)submitButton:(UIButton *)sender {
//Get stored username and password
NSDictionary *dict = [[NSDictionary alloc] initWithContentsOfFile:[[NSBundle mainBundle]pathForResource:#"profileDetails" ofType:#"plist"]];
NSString *usernameentered = dict[#"user"][#"username"];
NSString *passwordentered = dict[#"user"][#"password"];
if ([self.username.text isEqual:nil] || [self.username.text isEqual:#""]) {
//Show alert for empty username
}
else if ([self.password.text isEqual:nil] || [self.password.text isEqual:#""]) {
//Show alert for empty username
}
else if (![self.username.text isEqualToString:usernameentered]) {
//Show alert for wrong username
}
else if (![self.password.text isEqualToString:passwordentered]) {
//Show alert for wrong password
}
else {
//All validation is right.
//Move to other Viewcontroller
UIStoryboard *main = [UIStoryboard storyboardWithName:#"Main" bundle:nil];
NSString *Identifier = #"ViewController"; //Same as in storyboard
UIViewController *vc = [main instantiateViewControllerWithIdentifier:Identifier];
[self.navigationController pushViewController:vc animated:true]; //If you want to push
//[self.navigationController presentViewController:vc animated:YES completion:nil] //If you want to present
}
}