Libgdx changing animation during runtime?

Question

I've made an animation class that creates an animation for a player. However, I'm wondering how I can change the animation depending on where the player is currently moving? Heres my animation class:

public class AnimationTest extends ApplicationAdapter{
Batch batch;
private TextureAtlas textureAtlas;
private Animation animation;
private float elapsedTime = 0f;
private Sapien player;

public void create (Batch batch, String string, Sapien player) {
    this.batch = batch;
    this.player = player;
    textureAtlas = new TextureAtlas(Gdx.files.internal(string));
    animation = new Animation(1f/10f, textureAtlas.getRegions());
}

public TextureAtlas getTextureAtlas(){
    return new TextureAtlas(Gdx.files.internal("Player/Angle1/running/running.atlas"));
}

@Override
public void dispose() {
    batch.dispose();
    textureAtlas.dispose();
}

@Override
public void render () {
    elapsedTime += Gdx.graphics.getDeltaTime();
    //Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
    batch.begin();
    batch.draw((TextureRegion) animation.getKeyFrame(elapsedTime,true),player.getX(),player.getY(),75,75);
    batch.end();
}

I currently call create() and render() in another class.

public TiledTestTwo (int scale){
    this.scale = scale;
}

@Override
public void create () {
    View.createInstance(this.scale);
    float w = Gdx.graphics.getWidth();
    float h = Gdx.graphics.getHeight();

    player = new Player(animationTest.getTextureAtlas(),400,400,2);
    playerController = new PlayerController(player);
    camera = View.getInstance().createCamera(w, h);

    animationTest.create(View.getInstance().getBatch(), "Player/Angle1/idle/angle1IdleSheet.atlas", player);

    rounds = new Rounds(scale,w, h);
}

@Override
public void render () {
    //Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

    //animationTest.render();
    camera.update();
    View.getInstance().setView(camera);

    View.getInstance().render();
    animationTest.render();
    movableSubject.notifyUpdate();
    collisionController.checkCollisions(View.getInstance(), player, this.scale);

    ZombieObserver.getInstance().playerLocation((int) player.getX(),(int) player.getY());
    rounds.checkNewRound(player);
}

Answer 1

This is often achieved by loading all the relevant Animations in a separate class, and then referring to those animations from your player class based on some condition.

For example:

public class PlayerAnimations {
  public Animation<TextureRegion> walkLeft;
  public Animation<TextureRegion> walkRight;

  public PlayerAnimations() {
    walkLeft = new Animation(1f/10f, new TextureAtlas(Gdx.files.internal("player/walk/left.atlas")));      
    walkRight = new Animation(1f/10f, new TextureAtlas(Gdx.files.internal("player/walk/right.atlas")));      
  }
}

Then, in your player's render method you can check which direction the player is moving and pick the correct animation for that direction:

@Override
public void render () {
  elapsedTime += Gdx.graphics.getDeltaTime();
  Animation<TextureRegion> animation; // This is no longer set in the constructor, but picked here in render depending on the direction.

  if (isMovingLeft()) 
    animation = playerAnimations.walkLeft;
  else
    animation = playerAnimations.walkRight;
  batch.begin();
  batch.draw((TextureRegion) animation.getKeyFrame(elapsedTime,true),player.getX(),player.getY(),75,75);
  batch.end();
}