如何通过按钮有条件地调用情节提要面板场景

Question

I have an application who's first scene is a login screen. On pressing the login button, if the username and password are correct, the next scene should get called. Otherwise an alert is shown. But I am unable to figure out how to get the next scene conditionally.

if ([jsonDict valueForKey:@"success"] && [jsonDict valueForKey:@"redirect"]) {

                    NSLog(@"%@", [jsonDict valueForKey:@"success"]);
                    NSLog(@"%@", [jsonDict valueForKey:@"redirect"]);
                    NSString *redirect = [jsonDict valueForKey:@"redirect"];
                    [self performSegueWithIdentifier:@"next" sender:self];
                }
                else {
                    NSArray *jsonArray = [jsonDict valueForKey:@"errors"];
                    NSString *err = [jsonArray objectAtIndex:0];
                    NSLog(@"%@", err);
                    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Invalid Credentials!" message:err delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil];
                    [alert show];
                }

Answer 1

Set up a Segue to the next viewcontroller in your storyboard and give that segue a unique identifier. Then, if username and password are ok, just call

[self performSegueWithIdentifier:@"yourSegueIdentifier" sender:self];

Answer 2

Use below code:

- (void)validateLogin{
//code to check username and password are correct
if(correct){
[self performSegueWithIdentifier:@"SignInToNextScreen" sender:self];
}else{
 UIAlertView *myalert = [[UIAlertView alloc]initWithTitle:@"Login Failed" message:@"Invalid Username/Password" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];   
   }
 }

// SignInToNextScreen is a segue identifier for manually triggered segue.

Please see the attached screen shot