Applications are expected to have a root view controller at the end of application launch

Question

I get the following error in my console:

Applications are expected to have a root view controller at the end of application launch

Answer 1

There was a slight change around iOS 5.0 or so, requiring you to have a root view controller. If your code is based off older sample code, such as GLES2Sample, then no root view controller was created in those code samples.

To fix (that GLES2Sample, for instance), right in applicationDidFinishLaunching, I create a root view controller and attach my glView to it.

- (void) applicationDidFinishLaunching:(UIApplication *)application
{
  // To make the 'Application windows are expected
  // to have a root view controller
  // at the end of application launch' warning go away,
  // you should have a rootviewcontroller,
  // but this app doesn't have one at all.
  window.rootViewController = [[UIViewController alloc] init];  // MAKE ONE
  window.rootViewController.view = glView; // MUST SET THIS UP OTHERWISE
  // THE ROOTVIEWCONTROLLER SEEMS TO INTERCEPT TOUCH EVENTS
}

That makes the warning go away, and doesn't really affect your app otherwise.