ManagedScene.java

package mkat.apps.spacewars;

import org.andengine.entity.scene.Scene;

import android.util.Log;

public abstract class ManagedScene extends Scene {
	//Tells the Scene Manager that the managed scene either has or doesn't have a loading screen.
	public final boolean hasLoadingScreen;
	// The minimum length of time (in seconds) that the loading screen should be displayed.
	public final float minLoadingScreenTime;
	// Keeps track of how long the loading screen has been visible. Set by the SceneManager.
	public float elapsedLoadingScreenTime = 0f;
	//Is set TRUE if the scene is loaded.
	public boolean isLoaded = false;
	//Convenience constructor that disables the loading screen.
	public ManagedScene() {
		this(0f);
	}
	
	//Convenience constructor that sets the minimum length of the loading screen and sets hasLoadingScreen accordingly.
	public ManagedScene(final float pLoadingScreenMinimumSecondsShown) {
		minLoadingScreenTime = pLoadingScreenMinimumSecondsShown;
		hasLoadingScreen = (minLoadingScreenTime > 0f);
	}
	
	//Called by the Scene Manager. It calls onLoadScene if loading is needed, sets the isLoaded status, and pauses the scene while it's not shown.
	public void onLoadManagedScene() {
		if (!isLoaded) {
			Log.v("","Loading Scene");
			onLoadScene();
			isLoaded = true;
			this.setIgnoreUpdate(true);
		}
	}
	
	//Called by the Scene Manager. It calls onUnloadScene if the scene has been previously loaded and sets the isLoaded status.
	public void onUnloadManagedScene() {
		if (isLoaded){
			isLoaded = false;
			onUnloadScene();
		}
	}
	
	// Called by the Scene Manager. It unpauses the scene before showing it.
	public void onShowManagedScene() {
		this.setIgnoreUpdate(false);
		onShowScene();
		Log.v("","Showing  Scene");
	}
	
	//Called by the Scene Manager. It pauses the scene before hiding it.
	public void onHideManagedScene() {
		this.setIgnoreUpdate(true);
		ResourceManager.getInstance().engine.runOnUpdateThread(new Runnable() {
			@Override
			public void run() {
				onHideScene();
			}
		});
	}
	
	//Methods to Override in the subclasses.
	public abstract Scene onLoadingScreenLoadandShown();
	public abstract void onLoadingScreenUnloadAndHidden();
	public abstract void onLoadScene();
	public abstract void onShowScene();
	public abstract void onHideScene();
	public abstract void onUnloadScene();
}