过渡到导航视图控制器

Question

I have the following code:

- (IBAction)buttonPressed:(UIButton *)sender
{
    //sentder.titleLabel
    NSString *label = [(UIButton *)sender currentTitle];

    if ([label isEqualToString:@"Register"])
    {
        [sender setTitle:@"Registers" forState:UIControlStateNormal];

        RegisterViewController *viewCon = [[RegisterViewController alloc] init];
        RegisterNavigationController *navigation = [[RegisterNavigationController alloc] init];
    [navigation pushViewController:viewCon animated:YES];

        //self performSegueWithIdentifier:@"MySequeIdentifier" sender:];
    }
....

I have a startController with the following button code that gets called correctly. I created a brand new default registerViewController (UIViewController) and a registerNavigationContoller (UINavigationController class). How do I get my button click to animate to the registerViewController and have that view controller have a bar with a back button?

Am I doing this wrong, is the startViewController supposed to be a UINavigationController as it's just a UIViewController? If so how do I get rid of the top bar on this page?

Answer 1

You existing View Controller (the one containing this button code) needs to be contained within a Navigation Controller. The new VC will also be contained in the same Nav Controller. The Nav Controller manages the title bar and the back button navigation between these two child view controllers.

To embed the first VC in a Nav Controller:

• if using storyboard, you can select the view controller scene and then in the menu: Editor > Embed In > Navigation Controller

• if instantiating in code, first initialise the View Controller and then embed it in a new nav controller thus:

   UIViewController firstVC; firstVC = [[UIViewController alloc] initWithNib:@"nibname" bundle:nil]] //(example of initialising with a xib/nib file) UINavigationCOntroller navCon; navCon = [UINavigationController alloc] initWithRootViewController:firstVC]; 

  navController

Now from your button code you ask your parent navigation controller to manage the transition:

 RegisterViewController *viewCon = [[RegisterViewController alloc] init];  
    //take care to initialise correctly
    //do you have a nib file? a storyboard scene?
[self.navigationController pushViewController:viewCon animated:YES];

Alternatively you can create a storyboard push segue between the button and a second storyboard scene - which performs the same function as this code.

If you only want the navigation bar in the second VC, and not in the first, you have various options.

With each of your view controllers you can separately control the navigation controller's BOOL property navigationBarHidden - eg self.navigationController.navigationBarHidden = YES ;

But you may find the visual transition between navbar states unsatisfactory, and may want to consider alternative app designs. For example, you could present the second view controller from the first. In this case neither vcs need a navigation controller, (your second vc could contain it's own UINavigationBar instead). Or the presented view controller could still be embedded in it's own navigation controller. Either way you will not get an automatic back button to the first view controller and will need to implement your own (back buttons are provided only when one navigation controller is managing an array of child view controllers).

Those are just a few suggestions, you will have to play around with these - and other - ideas to work out what makes most sense for your app.