Develop Reference

Reloading Assets after android app has been paused

According to this libgdx wiki page https://github.com/libgdx/libgdx/wiki/Managing-your-assets OpenGL resources like Textures need to be reloaded after app has been paused.
Here is my way to manage libgdx app assets
I am loading all assets using assetManager during showing splashScreen using them whenever I need using assetManager.get()
Here is my code from the start:
public class GameMain extends Game {
private AssetManager manager;
#Override
public void create() {
manager = new AssetManager();
setScreen(new splashScreen(this));
}
#Override
public void render() {
super.render();
}
#Override
public void pause() {
super.pause();
}
#Override
public void resume() {
super.resume();
}
#Override
public void resize(int width, int height) {
super.resize(width, height);
}
#Override
public void dispose() {
super.dispose();
manager.dispose();
}
public AssetManager getAssetManager() {
return manager;
}
}
SplashScreen:
public class SplashScreen implements Screen {
GameMain gameMain;
public SplashScreen(GameMain gameMain) {
this.gameMain = gameMain;
}
#Override
public void show() {
loadAssets();
}
public void loadAssets() {
gameMain.getAssetManager().load("example.atlas", TextureAtlas.class);
gameMain.getAssetManager().finishloading();
}
}
My question:
Should I call manager.update() in each Screen.resume() or not?

Your implementation is fine, you do not need to manager.update() unless you are loading your assets asyncly. In this case you already loaded assets. But always reach your assets using get parameter.
If you dispose your texture onPause or onStop methods, you should reload them.

How to change gamestates in LibGdx using stacks

I am making a game in android like flappy bird and I am able to go from the menu state to the playState but when the game is over and when I try to get the menu state back it just gives me the background or sometimes a white screen.
public class FlappyDemo extends ApplicationAdapter {//ApplicatoonListener
public static final int width=480;
public static final int height=800;
public static final String title="Flappy Bird";
public GameStateManager gsm;
/*private*/public SpriteBatch spriteBatch;
public void create () {
spriteBatch=new SpriteBatch();
gsm=new GameStateManager();
gsm.push(new MenuState(gsm));
Gdx.gl.glClearColor(1,1,1,1);
}
#Override
public void render () {
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
gsm.update(Gdx.graphics.getDeltaTime());
gsm.render(spriteBatch);
}
}
public abstract class State {
OrthographicCamera cam;
Vector3 mouse;
GameStateManager gsm;
public State(GameStateManager gsm){
this.gsm=gsm;
mouse=new Vector3();
cam = new OrthographicCamera();
}
public abstract void handleInput();
public abstract void update(float dt);
public abstract void render(SpriteBatch sb);
public abstract void dispose();
}
public class GameStateManager {
private Stack<State> states;
public GameStateManager(){
states=new Stack<State>();
}
public void push(State state){
states.push(state);
}
public void pop(){
states.pop();
}
public void set(State state){
states.pop().dispose();
states.push(state);
}
public void update(float dt){
states.peek().update(dt);
}
public void render(SpriteBatch sb){
states.peek().render(sb);
}
}
public class MenuState extends State {
Texture background;
Texture playBtn;
public MenuState(GameStateManager gsm) {
super(gsm);
background=new Texture("bg.png");
playBtn=new Texture("buttonflappy.jpg");
}
#Override
public void handleInput() {
if(Gdx.input.isTouched()) {
gsm.push(new PlayState(gsm));
}
}
#Override
public void update(float dt) {
handleInput();
}
#Override
public void render(SpriteBatch sb) {
sb.begin();
sb.draw(background,0,0, 1100,1800);
sb.draw(playBtn,1100/2, 1800/2);
sb.end();
}
#Override
public void dispose() {
playBtn.dispose();
background.dispose();
}
}
so first I call the push method and pass it the MENUSTATE and than in the menustate I call the push method and pass it the PlayState to start the game and in the PLayState I have got the gameplay, cameras,viewports. Now when I say that if the bird hits the tube or the ground the menustate should be called again all I get is a green screen which is the background of the playstate.
if (tube.collide(bird.getBirdBound())) {
gsm.set(new MenuState(gsm));
}
if (bird.getPosition().y <= ground.getHeight() + offset) {
gsm.set(new MenuState(gsm));
}
this is the calling method to the gamestate manager when the game ends and the menustate should be called.
So can anyone tell me how can I get the menustate back instead of getting the background color i.e green.
Really appreciate if anyone could help.

You do not clear the previously rendered color to the framebuffer. I see you only call glClearColor on create. Try this render method:
#Override
public void render () {
Gdx.gl.glClearColor(1,1,1,1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
gsm.update(Gdx.graphics.getDeltaTime());
gsm.render(spriteBatch);
}

I finally got it the problem was that I was not changing the camera position. SO what I did was that in the menustate I used the camera and set its position cam.setToOrtho(false,1100,1800) the position where I had drawn the background and updated the camera so now when in the playstate I poped the current state and went back to to the menustate my camera was pointing at the menustate insted of the green color.

Stage doesn't get drawn

I created a super class with nothing in the render method:
public class SuperClass implements InputProcessor {
public SuperClass(MyGame game) {
}
public void render() {
}
// InputProcessor overriden methods here
}
In a subclass I override the render method:
public class SubClass extends SuperClass {
Stage stage;
public SubClass(MyGame game) {
super(game);
stage = new Stage(0, 0, false);
skin = new Skin(Gdx.files.internal("data/uiskin.json"));
Gdx.input.setInputProcessor(stage);
Image image = new Image(new Texture(Gdx.files.internal("bg.png")));
image.setPosition(0, 0);
image.setWidth(800);
image.setHeight(480);
stage.addActor(image);
}
#Override
public void render() {
stage.act(Gdx.graphics.getDeltaTime());
stage.draw();
}
}
But the stage doesn't get drawn. I know this because I expect to see the background image but its just a blank screen.
What am I doing wrong here?

You should be calling your SuperClass render method in your MyGame render method.

Is your render() method being called each game loop?
What I do normally is to create an Object which extends Game and set a Screen.
class MyGame extends Game {
#Override
public void create() {
setScreen(new MainScreen());
}
}
In the MainScreen class which implements Screen interface I can create my stage:
class MainScreen implements Screen {
Stage stage = new Stage(0, 0);
#Override
public void dispose() {
stage.dispose();
}
#Override
public void hide() {
}
#Override
public void pause() {
}
#Override
public void render(float delta) {
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
stage.act(Gdx.graphics.getDeltaTime());
stage.draw();
}
#Override
public void resize(int width, int height) {
}
#Override
public void resume() {
}
#Override
public void show() {
stage = new Stage(0, 0, false);
skin = new Skin(Gdx.files.internal("data/uiskin.json"));
Gdx.input.setInputProcessor(stage);
Image image = new Image(new Texture(Gdx.files.internal("bg.png")));
image.setPosition(0, 0);
image.setWidth(800);
image.setHeight(480);
stage.addActor(image);
}
}
With this code the render() method should be called in each game loop.

The line in the SubClass constructor should be:
stage = new Stage(800, 480, false);
or you can also do this:
stage = new Stage()
but then you have to set the viewport, stage.setViewport(float, float, boolean) in resize(float, float).

Enum acts strange in TouchEvent

I have some trouble with my enum in my touchDown method from InputProcessor. When I try to use it it generates all the possible enums...
public class Memoration implements ApplicationListener, InputProcessor {
public static enum Screen {GAME, MENU}
Screen screen;
#Override
public void create() {
screen = Screen.MENU;
Gdx.app.log("onCreate", "works");
Gdx.input.setInputProcessor(this);
}
#Override
public void dispose() {
}
#Override
public void render() {
// bla bla bla
}
#Override
public boolean touchDown(int screenX, int screenY, int pointer, int button) {
Gdx.app.log("touch", "down");
if(screen == null)
Gdx.app.log("screen", "null");
if(screen == Screen.MENU)
Gdx.app.log("screen", "menu");
if(screen == Screen.GAME)
Gdx.app.log("screen", "game");
return false;
}
}
The log show us "onCreate: workds", "touch: down", "screen: null", "screen: menu" and "screen: game"

Your class is called Memoration and implements InputProcessor. However, in your create() callback, you are creating another instance of Memoration and setting that as the input processor, so it's that instance that is getting the callbacks. And, because create() isn't being called for that instance, screen is never initialized.
Try this instead...
#Override
public void create() {
screen = Screen.MENU;
Gdx.app.log("onCreate", "works");
Gdx.input.setInputProcessor(this);
}

InputProcessor of libgdx does not fire

I'm trying to get a simple libgdx project running on Android. Everything is fine, but my InputProcessor does not fire its events.
I implemented everything according to this tutorial:
http://code.google.com/p/libgdx-users/wiki/IntegratingAndroidNativeUiElements3TierProjectSetup#Code_Example
The first call of "showToast" works fine and is shown on my screen => The showToast-Method does work. Unfortunately, I can't fire any of the InputProcessor events. Even the debugger does not stop there, so they are definitely not called.
Edit: Here is the complete code. I only omitted the Calculator Class, since it works fine and should not be of any conern here. If anyone disagrees with that I can always add it, of course.
Surface Class in libgdx main project (Main class so to say)
public class Surface implements ApplicationListener {
ActionResolver actionResolver;
SpriteBatch spriteBatch;
Texture texture;
Calculator calculator;
public Surface(ActionResolver actionResolver) {
this.actionResolver = actionResolver;
}
#Override
public void create() {
spriteBatch = new SpriteBatch();
texture = new Texture(Gdx.files.internal("ship.png"));
calculator = new Calculator(texture);
actionResolver.showToast("Tap screen to open Activity");
Gdx.input.setInputProcessor(new InputProcessor() {
#Override
public boolean touchDown(int x, int y, int pointer, int button) {
actionResolver.showToast("touchDown");
actionResolver.showMyList();
return true;
}
// overriding all other interface-methods the same way
});
}
#Override
public void render() {
Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
calculator.update();
spriteBatch.begin();
calculator.draw(spriteBatch);
spriteBatch.end();
}
// Overriding resize, pause, resume, dispose without functionality
}
ActionResolver interface in libgdx main project
public interface ActionResolver {
public void showMyList();
public void showToast(String toastMessage);
}
Implementation of the ActionResolver interface within my Android project
public class ActionResolverImpl implements ActionResolver {
Handler uiThread;
Context appContext;
public ActionResolverImpl(Context appContext) {
uiThread = new Handler();
this.appContext = appContext;
}
#Override
public void showMyList() {
appContext.startActivity(new Intent(this.appContext, MyListActivity.class));
}
#Override
public void showToast(final String toastMessage) {
uiThread.post(new Runnable() {
#Override
public void run() {
Toast.makeText(appContext, toastMessage, Toast.LENGTH_SHORT).show();
}
});
}
}
Android Activity for inizializing the Suface-Class
public class AndroidActivity extends AndroidApplication {
ActionResolverImpl actionResolver;
#Override
public void onCreate(android.os.Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
actionResolver = new ActionResolverImpl(this);
initialize(new Surface(actionResolver), false);
}
}
I also implemented the InputProcessor in my Surface-class, but this should not (and did not) make any difference. Any ideas, what I'm missing?