AppState documentation refers to non-existent app.getRootNode()

Documentation
1

The documentation for AppState, specifically the code related to AbstractAppState, has the following:

@Override
public void initialize(AppStateManager stateManager, Application app) {
    // [...]
    this.app.getRootNode().attachChild(getX());

However, the Application class doesn’t contain a getRootNode() method in version 3.2.2, so this code doesn’t compile.

If this could be fixed to reflect the current API, I would be obliged.

2

The documentation looks correct to me. The example shows app as a SimpleApplication. The assignment to app casts the Application object to a SimpleApplication object.

public class MyAppState extends AbstractAppState {

    private SimpleApplication app;

    private Node x = new Node("x");  // some custom class fields...
    public Node getX(){ return x; }  // some custom methods...

    @Override
    public void initialize(AppStateManager stateManager, Application app) {
      super.initialize(stateManager, app);
      this.app = (SimpleApplication)app;          // cast to a more specific class

      // init stuff that is independent of whether state is PAUSED or RUNNING
      this.app.getRootNode().attachChild(getX()); // modify scene graph...
      this.app.doSomething();                     // call custom methods...
   }

   @Override
    public void cleanup() {
      super.cleanup();
      // unregister all my listeners, detach all my nodes, etc...
      this.app.getRootNode().detachChild(getX()); // modify scene graph...
      this.app.doSomethingElse();                 // call custom methods...
    }

    @Override
    public void setEnabled(boolean enabled) {
      // Pause and unpause
      super.setEnabled(enabled);
      if(enabled){
        // init stuff that is in use while this state is RUNNING
        this.app.getRootNode().attachChild(getX()); // modify scene graph...
        this.app.doSomethingElse();                 // call custom methods...
      } else {
        // take away everything not needed while this state is PAUSED
        ...
      }
    }

    // Note that update is only called while the state is both attached and enabled.
    @Override
    public void update(float tpf) {
      // do the following while game is RUNNING
      this.app.getRootNode().getChild("blah").scale(tpf); // modify scene graph...
      x.setUserData(...);                                 // call some methods...
    }

}
3

AKA:

!=

1 Like
4

Yes, it looks like I was missing the cast. In my code, I didn’t have the line

this.app = (SimpleApplication)app;          // cast to a more specific class

My code implements the Application interface, rather than subclassing the SimpleApplication class (I’m trying to be future-compatible, given that I read that the plan was to switch to Application as an interface, since “SimpleApplication especially is a mess”). It seems the documentation has an implicit assumption that users are still using SimpleApplication, hence my confusion.

So I guess that it does work correctly as-is and doesn’t necessarily need to be fixed. It’s just confusing for those using the newer Application interface.l

5

You should continue to use SimpleApplication or you will end up providing all of these helper methods yourself.

SimpleApplication will not disappear. There will just be an alternative someday… and a migration path to get there should you decide to.

Even I still extend SimpleApplication even though I’m the one who started the refactoring. I just generally ignore everything about SimpleApplication except the super(AppState…) constructor and simpleInit().

1 Like