Question

I’d like to have a view appear when the user clicks a button. The hierarchy I have looks like this:

MainWindow

-UIView
--ScrollView
---ScrollView.pages = UIViews
----UIView (from above assignment)
----TextView
----InfoButton

pages is an NSMutableArry of pageController objects. These hook to a nib. These nibs are the pages that user flicks through in the scroll view.

The InfoButton click is wired up like this:

- (IBAction) infoButton_click:(id)sender{
topView topViewViewController *topView = [[topViewViewController alloc] initWithNibName:@"TopView" bundle:[NSBundle mainBundle]];
//[self.navigationController pushViewController: topViewView animated:YES]; 
//[self.view addSubview: topViewView.view];
[super.view addSubview: topViewView.view];
[topViewView release];
}

InfoButton is on one of the pages in the ScrollView. I’ve commented out different code that has been tried. None of it adds the view. Nothing happens. Is there a way to get TopView as the top view in the hierarchy?

Answer 1

Is your goal to add the view as a subview, or to slide on a new view using the navigation controller? I’m going to assume the latter for the moment.

- (IBAction)infoButton_click:(id)sender
{
    TopViewController *topViewController = [[TopViewController alloc] initWithNibName:@"TopView" bundle:nil];
    [self.navigationController pushViewController:topViewController animated:YES]; 
    [topViewController release];
 }

This is correct if you actually have a navigationController. Make sure you actually do. When “nothing happens” in Cocoa, it usually means something is nil. You should check in the debugger or with NSLog() to see if any of these values are nil. It is possible (even likely), that your parent has a navigationController, but you do not.

Classes should always have a leading capital. Do not create a variable called “view” that is of class “UIViewController”. This is a sure path to suffering. Objective-C is a dynamic language with limited compiler checks on types. Naming things correctly is critical to effective programming in ObjC.