Navigating between several views in iphone

Question

Hi I have three views and I would like to achieve something that doesn't work. I have a main view if user presses a certain button the code checks if he is logged or not: if yes he is sent directly to view B if not first he goes to login view. After successfull login I have this code to go to view b:

incidencias =[[MisIncidencias alloc]
              initWithNibName:@"MisIncidencias"
              bundle:nil];

[self.view addSubview:incidencias.view];

the thing is I would like to get rid of the login view because it shows there underneath plus if user clicks back it goes back to login but if I add:

[self.view removeFromSuperview];

either before or after [self.view addSubview:incidencias.view], I just get redirected to the main view;

I don't know if I explained myself clearly but for example in Android you can just call finish and then call next activity and the login activity disappears but here in iphone I don't know what to do.

I have found another solution is to add both views one after another but it doesn't really work well:

incidencias=[[MisIncidencias alloc]
                  initWithNibName:@"MisIncidencias"
                  bundle:nil
                  ];

    [self.view addSubview:incidencias.view];

    login=[[LoginViewController alloc]
                  initWithNibName:@"LoginViewController"
                  bundle:nil];
    [self.view addSubview:login.view];

it doesn't work well because incidencias starts and doesn't wait for login to finish.

thanks

EDIT: thanks to beOn I have modified my code adding the protocol: LoginViewControllerDelegate and this method inside viewController:

- (void)loginSucceededFromController:(LoginViewController*)viewController {
[viewController.view removeFromSuperview];

incidencias =[[MisIncidencias alloc]
              initWithNibName:@"MisIncidencias"
              bundle:nil];

[self.view addSubview:incidencias.view];
}

in LoginViewController I have

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

if(self.delegate)
    [self.delegate loginSucceededFromController:self]

} it gets an error: Semantic Issue: Property 'delegate' not found on object of type 'LoginViewController *'

if login is successful the user sees an alert and once he clicks on ok is when the method above gets called.

what else should I add? I am beginning with iphone and I don't understand very well what is delegate (I come from java)

Answer 1

If you want something working right away, and you are using uinavigationcontroller... then u can possibly make use of

- (void)setViewControllers:(NSArray *)viewControllers animated:(BOOL)animated

just get a mutable copy of the self.navigationController.viewcontrollers array, pop out the last element, which will be the login screen and push in the new screen where you are planning to move screen b.. and pass the array to this function.. and you are now safe!

Answer 2

Ah, okay, this ain't so bad. Here's the first solution that comes to mind:

Step 1. Create a delegate protocol for your login view.

@protocol LoginViewControllerDelegate <NSObject>
@required
- (void)loginSucceededFromController:(LoginViewController*)viewController;
@end

Step 2. Implement the protocol in your main view controller

- (void)loginSucceededFromController:(LoginViewController*)viewController {
// TODO: we'll put something here in a second
}

Step 3. Call the delegate method from your login view on successful login

if (loginSuccess && self.delegate) {
    [self.delegate loginSucceededFromController:self]
}

Step 4. Dismiss the login view and present the new view from the main view controller using the code you already have:

- (void)loginSucceededFromController:(LoginViewController*)viewController {
    [viewController.view removeFromSuperview];

    incidencias =[[MisIncidencias alloc]
                  initWithNibName:@"MisIncidencias"
                  bundle:nil];

    [self.view addSubview:incidencias.view];
}

Hopefully that clears things up some. The reason you were having trouble is that you were either adding a subview to a view, then immediately removing the view, or removing the view, then adding a subview to it. In the code above, you call the view's controller's delegate, and the delegate, which happens to own the superview of the view, first removes the view, then adds a newView (for lack of a better term) to the superview. Since the superview was never removed, it's able to show your newView.

Answer 3

You have to take BOOL which one can access through out application like global

like extern BOOL login; now once you login set to YES. now check when

if(login == YES){

incidencias=[[MisIncidencias alloc]
                  initWithNibName:@"MisIncidencias"
                  bundle:nil
                  ];

    [self.view addSubview:incidencias.view];

}
else{
login=[[LoginViewController alloc]
                  initWithNibName:@"LoginViewController"
                  bundle:nil];
    [self.view addSubview:login.view];
}