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How to manipulate characters and objects in LibGDX

I am new to programming in LibGDX and I'm currently working on a simple arcade game. And I would like to know how should I properly create a main character who just has to run and jump? Should I create a new class for him and implement some method? As for now, I have only two classes, MyGame where I handle the other game states and PlayState where I draw the background and objects.

Just create a Sprite, you can control it easily.
SpriteBatch batch;
Sprite sprite;//Main character
#Override
public void create(){
batch = new SpriteBatch();
sprite = new Sprite(new Texture(Gdx.files.internal("data/text.png")));
}
#Override
public void render(){
//Add logic to control the main character...
batch.begin();
sprite.draw(batch);
batch.end();
}
If you want to create more methods you could try extending the Actor class too, this way it can be reused.
public class MyActor extends Actor{
Texture texture = new Texture(Gdx.files.internal("data/tex.png"));
float actorX = 0, actorY = 0;
public MyActor(){
addListener(new InputListener(){//Receive events
public boolean touchDown (InputEvent event, float x, float y, int pointer, int button){//Check your run and jump buttons
//...
}
}
#Override
public void draw(Batch batch, float alpha){//Draw it
batch.draw(texture,actorX,actorY);
}
#Override
public void act(float delta){//Update it
}
}

Control sprite rotation (it's spinning like crazy)

So, I have created a texture, and then a sprite.
On my render() method, I am check for user input. If the user has touched/clicked, then I want my sprite to rotate 90 degrees ONCE.
Right now the rotation works. However, it rotates multiple times per click!
How can I make it rotate only once per touch? I have a feeling that I might have to use delta time, and that occurs because the render method is being called frequently, but I don't know how to fix it... Thanks!
public class MyGame extends ApplicationAdapter {
SpriteBatch batch;
Texture img;
Sprite sprite;
#Override
public void create () {
batch = new SpriteBatch();
img = new Texture("badlogic.jpg");
sprite = new Sprite(img);
}
#Override
public void render () {
Gdx.gl.glClearColor(1, 1, 1, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
batch.begin();
sprite.draw(batch);
batch.end();
if (Gdx.input.isTouched()) {
rotateRight();
}
}
private void rotateRight() {
sprite.setRotation(sprite.getRotation() - 90);
}
}

Right now you are polling input inside of your render method. Polling simply checks the status of the input (is it touched or not) and does not care for any actual "event" occurred.
Instead of this you need to look for input events via event handling as this will give you access to the actual event of the screen being touched or untouched. You can do this by implementing InputProcessor which will give you access to override a bunch of touch event methods so you can execute your rotate method only on the event of the touch.
Example:
public void update()
{
Gdx.input.setInputProcessor(new InputProcessor() {
#Override
public boolean TouchDown(int x, int y, int pointer, int button) {
if (button == Input.Buttons.LEFT) {
rotateRight();
return true;
}
return false
}
});
}
Don't forget to call your update() method from your render method. I put it in a separate function just for readability and not to clog up your rendering code.
You can also have your class implement InputProcessor and override the methods in your class so you do not have to do it inline as I did above.

if (Gdx.input.justTouched() && Gdx.input.isTouched()) {
rotateRight();
}

Libgdx InputListener "exit()" is not being called with TextButton

I want to use the exit() method in the InputListener to see wheter the cursor is inside the button or not.
Here is the explanation in the libGDX docs.
public void exit(InputEvent event, float x, float y, int pointer, Actor toActor)
Called any time the mouse cursor or a finger touch is moved out of an actor.
But when I put my cursor on the button and then move it outside the button, the method is not called. I am testing it by a System.out.println("exited"); and I get nothing in the console.
EDIT:
LibGDX Version: Latest Stable Nightlies
InputListener implementation:
//This button class is a custom class to make button creation easier. This is the constructor.
public Button(Vector2 position, String packLocation, String text, Stage stage, BitmapFont font, Color color) {
//Removed buttonStyle creation etc. to shorten the code.
button = new TextButton(text, buttonStyle);
button.setPosition(position.x, position.y);
stage.addActor(button);
Gdx.input.setInputProcessor(stage);
pressed = false;
button.addListener(new ClickListener() {
#Override
public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
pressed = true;
return true;
}
#Override
public void touchUp(InputEvent event, float x, float y, int pointer, int button) {
pressed = false;
}
#Override
public void exit(InputEvent event, float x, float y, int pointer, Actor toActor) {
System.out.println("exited");
}
});
}
EDIT:
Hovering over the button also does not change the texture of the button as I set it to like so:
buttonStyle.over = skin.getDrawable("over");
But clicking does.

After searching for a couple hours I finally found what was missing. stage.act(); had to be called in the render method. This both gave functionality to the texture change when we hover over the button and also the enter/exit methods in the InputListener.

Moving a Sprite using a Scene2d button

I am creating an Android Game using LibGdx. It is a platformer and the map is tiled based. To test the movements of the player I used Key inputs and the desktop version of the game works fine. I created some buttons in scene2d and added them as an actor to the scene so that the game has movement buttons when played on Android devices. The buttons work as "System.out.print" shows. Problem is: the buttons and the player are each created in a different class. I can't seem to modify the velocity (and so the movement) of the Player from the class that holds the buttons. For that I need to change the velocity and speed etc. to static, which gives me strange errors on an Android device (Player won't show, or disappears after a frame). I am not sure how to fix this and what is the actual cause of this error. Here is some of the code of the different Classes:
Main Class (MyGdxGame) only included one button as an example.
public class MyGdxGame extends Game implements ApplicationListener {
private Skin skin;
private Stage stage;
#Override
public void create() {
setScreen(new Play());
skin = new Skin(Gdx.files.internal("ui/defaultskin.json"));
stage = new Stage();
Gdx.input.setInputProcessor(stage);
//Button Right
TextButton buttonRight = new TextButton("Right", skin, "default");
buttonRight.setWidth(50f);
buttonRight.setHeight(50f);
buttonRight.setPosition(Gdx.graphics.getWidth() /2 - 250f, Gdx.graphics.getHeight()/2 - 200f);
buttonRight.addListener(new ClickListener(){
public boolean touchDown (InputEvent event, float x, float y, int pointer, int button) {
System.out.println("Hold");
return true;
}
public void touchUp (InputEvent event, float x, float y, int pointer, int button) {
System.out.print("Released");
}
});
stage.addActor(buttonRight);
}
Play Class
public class Play implements Screen {
private TiledMap map;
private OrthogonalTiledMapRenderer renderer;
private OrthographicCamera camera;
private Player player;
#Override
public void render(float delta) {
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
camera.position.set(Gdx.graphics.getWidth() / 2, Gdx.graphics.getHeight() / 2, 0);
camera.update();
renderer.setView(camera);
renderer.render();
renderer.getSpriteBatch().begin();
player.draw(renderer.getSpriteBatch());
renderer.getSpriteBatch().end();
}
#Override
public void resize(int width, int height) {
camera.viewportWidth = width;
camera.viewportHeight = height;
}
#Override
public void show() {
map = new TmxMapLoader().load("maps/map.tmx");
renderer = new OrthogonalTiledMapRenderer(map);
camera = new OrthographicCamera();
player = new Player(new Sprite(new Texture("data/jack2.png")), (TiledMapTileLayer) map.getLayers().get(0));
player.setPosition(2 * player.getCollisionLayer().getTileWidth(), 10 * player.getCollisionLayer().getTileHeight());
}
Player Class
public class Player extends Sprite implements InputProcessor{
// the movement velocity //
public Vector2 velocity = new Vector2();
public float speed = 60 * 2, gravity = 60 * 1.8f;
private boolean canJump;
private TiledMapTileLayer collisionLayer;
private String blockedKey = "blocked";
public Player(Sprite sprite, TiledMapTileLayer collisionLayer){
super(sprite);
this.collisionLayer = collisionLayer;
}
#Override
public void draw(SpriteBatch spriteBatch) {
update(Gdx.graphics.getDeltaTime());
super.draw(spriteBatch);
}
So the button has a working ClickListener, but I don't know how it can modify the players velocity. Any help is welcome.

You just need to have some way to access that player instance from the class containing the button. In my games I make a static World class which can be accessed from anywhere in the program. Through the world class I can access the player instance. That's just how I do it, you may find another way. You say your program has errors on android device when making certain parameters static? Do you mean it compiles but it just doesn't work the way you expect? If that's the case, there is probably just a bug in how you're modifying the position or velocity of the player.

Cannot get events working in my libgdx Actor

I'm having a hard time getting events working with my Actor in libgdx. I'm using nightly builds.
My stage is setup in the show() method of a Screen subclass:
stage = new Stage(Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), true);
Gdx.input.setInputProcessor(stage);
TestActor actor = new TestActor();
stage.addActor(actor);
And my actor class looks like:
class TestActor extends Actor {
private Sprite sprite;
private TextureAtlas atlas;
public TestActor() {
atlas = new TextureAtlas(Gdx.files.internal("textures/images-packed.atlas"));
sprite = atlas.createSprite("logo-96");
setTouchable(Touchable.enabled);
addListener(new InputListener() {
public boolean touchDown (InputEvent event, float x, float y, int pointer, int button) {
Gdx.app.debug(TestGame.TAG, "TestActor.touchDown()");
return true; // must return true for touchUp event to occur
}
public void touchUp (InputEvent event, float x, float y, int pointer, int button) {
Gdx.app.debug(TestGame.TAG, "TestActor.touchUp()");
}
});
}
#Override
public void draw(SpriteBatch batch, float parentAlpha) {
Color color = getColor();
batch.setColor(color.r, color.g, color.b, color.a * parentAlpha);
batch.draw(sprite, getX(), getY());
}
}
The events don't seem to fire. Oddly enough, I've used built-in UI widgets like the TextButton and can get those events to fire just fine. Can anybody see what I'm doing wrong?

You should also setBounds to your actor.
best way to do it (if you want the same size as your texture)
add these lines to your constructor :
setWidth(sprite.getWidth());
setHeight(sprite.getHeight());
setBounds(0, 0, getWidth(), getHeight());
notice you can also set the location of the bounds with the first 2 parameters.