How to load subview from the main view?

Question

Hi,

I am very new to Obj-C and learning iphone development. My question is how to add subview from app delegate. Lets say I added subview called "MainView" from "applicationDidFinishLaunching" method.

- (void)applicationDidFinishLaunching:(UIApplication *)application {    

MainViewController *aViewController = [[MainViewController alloc] initWithNibName:@"MainView" bundle:nil];
self.mainViewController = aViewController;
[aViewController release];

[window addSubview:mainViewController.view];
// Override point for customization after application launch
[window makeKeyAndVisible];

}

"MainView.xib" file has a button to show its child view. When the button is clicked, it calls "showChildView" method.

- (IBAction)showChildView:(id)sender {
    if (self.childViewController == nil) {
     ChildViewController *childController = [[ChildViewController alloc] initWithNibName:@"ChildView" bundle:nil];
     self.childViewController = childController;
     [childController release];
    }

    [self.view insertSubview:childViewController.view atIndex:0];
}

From this code, when app launches, it shows "MainView" with a button. But when I clicked the button, the button is still visible as well as the content from the "ChildView.xib" file too.

How can I hide the "MainView" when I pressed the button and show only the contents of the "ChildView"?

Thanks for your help in advance.

Answer 1

well, you have to remove the original view first, before inserting the new subview, do it this way

- (IBAction)showChildView:(id)sender {
    if (self.childViewController == nil) {
        ChildViewController *childController = [[ChildViewController alloc] initWithNibName:@"ChildView" bundle:nil];
        self.childViewController             = childController;
        [childController release];
    }
    [self.mainViewControlle.view removeFromSuperView];
    [self.view insertSubview:childViewController.view atIndex:0];
}

Hope this helps.

Answer 2

You might want to check out the Utility App sample -- it demonstrates switching between two views with animation and adding/removing views from parent views.

Answer 3

you might want to create a navigation controller in the main view and than push the childviewcontroller onto it when invoking showChildView. You'll get the back navigation button for free that way