Is this a correct way to add/remove views?

[objlv]

Lets say that I have 4 view controllers (call them FirstView,SecondView,ThirdView,FourthView) which are created programmatically and all are in separate files:

In AppDelegate.m didFinishLaunchingWithOptions method I have these lines of code

self.rootViewController = [[rootViewController alloc]initWithNibName:@"rootViewController" bundle:nil];
self.window.rootViewController = self.rootViewController;

In rootViewController.m loadview method I have

self.view = [[UIView alloc]initWithFrame:[UIScreen mainScreen].applicationFrame];
self.firstView = [[FirstView alloc]init];
[self.view addSubview:self.firstView.view];

That code works fine - first view is displayed.

Let's continue

In FirstView.m switchViews method

NOTE: Please see the comments in code

self.secondView = [[SecondView alloc] initWithNibName:@"SecondView" bundle:nil];


// I think here secondView is added to rootViewController - right ?
[self.view.superview addSubview:self.secondView.view];

// Here first view is removed from rootViewController - right ?
[self.view removeFromSuperview];
Here is how I add/remove views.

Is this approach correct? Can you recommend a better solution?

I have read about UINavigationController, but I don't think it could be a solution in this case.

[Duncan C]

Originally Posted by objlv

Lets say that I have 4 view controllers (call them FirstView,SecondView,ThirdView,FourthView) which are created programmatically and all are in separate files:

In AppDelegate.m didFinishLaunchingWithOptions method I have these lines of code

self.rootViewController = [[rootViewController alloc]initWithNibName:@"rootViewController" bundle:nil];
self.window.rootViewController = self.rootViewController;

In rootViewController.m loadview method I have

self.view = [[UIView alloc]initWithFrame:[UIScreen mainScreen].applicationFrame];
self.firstView = [[FirstView alloc]init];
[self.view addSubview:self.firstView.view];

That code works fine - first view is displayed.

Let's continue

In FirstView.m switchViews method

NOTE: Please see the comments in code

self.secondView = [[SecondView alloc] initWithNibName:@"SecondView" bundle:nil];


// I think here secondView is added to rootViewController - right ?
[self.view.superview addSubview:self.secondView.view];

// Here first view is removed from rootViewController - right ?
[self.view removeFromSuperview];
Here is how I add/remove views.

Is this approach correct? Can you recommend a better solution?

I have read about UINavigationController, but I don't think it could be a solution in this case.

No, it is not the right way to do it.

A view controller is supposed to manage the entire screen. You're not supposed to mix content from more than one view cotroller on the screen at a time. Doing so causes a variety of problems, including auto-rotation problems and memory problems.

If you're willing to limit yourself to iOS 5 and later, it is now supported. View controllers now let you register child view controllers who's content can be hosted by another view controller.

If you don't want to limit yourself to iOS 5 and later, you should refactor your code so a single view controller manages all the views. Then you could use normal view code to swap views in and out.

[objlv]

Thanks !
Аs far as I understand, you suggest me to create UIViewController and that controller to be set to window.rootViewController. Then that UIViewController should manage different UIView's, right ?

[Duncan C]

Originally Posted by objlv

Thanks !
Аs far as I understand, you suggest me to create UIViewController and that controller to be set to window.rootViewController. Then that UIViewController should manage different UIView's, right ?

Correct.

You don't have to limit yourself to a single view controller, just one at a time. You can still use a navigation controller or tab bar controller to manage multiple view controllers, or push a modal view controller, or various other options built into iOS.

[Feldspar]

You can also subclass UIView instead of UIViewController to retain some modularity, but some things still need to be handled by the controller.