LibGDX crashes when creating a button - libgdx

Question

I'm new to LibGdx. I have been programming java for a year, but today I got an error with a Button in LibGdx.
What's causing it, and how can I fix it?
#Override
public void render(float delta) {
Gdx.gl.glClearColor(1, 1, 1, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
batch.begin();
background.draw(batch);
batch.end();
}
#Override
public void show() {
batch = new SpriteBatch();
// THE ERROR IS HERE|
// V
// BUTTON
Skin skinLibgdx = new Skin();
TextureAtlas ta = new TextureAtlas(Gdx.files.internal("Button.pack"));
skinLibgdx.addRegions(ta);
Button button = new Button(skinLibgdx);
button.addListener(new ClickListener() {
#Override
public void clicked(InputEvent event, float x, float y) {
// TODO Auto-generated method stub
System.out.println("ABC");
}
});
}
...
}
error:
Exception in thread "LWJGL Application" com.badlogic.gdx.utils.GdxRuntimeException: No com.badlogic.gdx.scenes.scene2d.ui.Button$ButtonStyle registered with name: default
at com.badlogic.gdx.scenes.scene2d.ui.Skin.get(Skin.java:145)
at com.badlogic.gdx.scenes.scene2d.ui.Skin.get(Skin.java:132)
at com.badlogic.gdx.scenes.scene2d.ui.Button.<init>(Button.java:50)
at com.me.game.screen.MainMenu.show(MainMenu.java:53)
at com.badlogic.gdx.Game.setScreen(Game.java:61)
at com.me.game.screen.Splash$1.onEvent(Splash.java:64)
at aurelienribon.tweenengine.BaseTween.callCallback(BaseTween.java:380)
at aurelienribon.tweenengine.BaseTween.updateStep(BaseTween.java:521)
at aurelienribon.tweenengine.BaseTween.update(BaseTween.java:424)
at aurelienribon.tweenengine.TweenManager.update(TweenManager.java:166)
at com.me.game.screen.Splash.render(Splash.java:35)
at com.badlogic.gdx.Game.render(Game.java:46)
at com.me.game.MainGame.render(MainGame.java:16)
at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:207)
at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:114)

Answer 1

The atlas alone is not enough for the button. You would have to provide a default style for the button. This either can be done directly on the skin or by a JSON file you can load. Check https://github.com/libgdx/libgdx/wiki/Skin for the details.
Check the tests of libgdx, that contain a rather complete example (https://github.com/libgdx/libgdx/blob/master/tests/gdx-tests-android/assets/data/uiskin.json).
e.g.
...
com.badlogic.gdx.scenes.scene2d.ui.Button$ButtonStyle: {
default: { down: default-round-down, up: default-round },
toggle: { down: default-round-down, checked: default-round-down, up: default-round }
},
...
And then load it e.g.
Skin skinLibgdx = new Skin(Gdx.files.internal("data/uiskin.json"))
See a whole example: https://github.com/libgdx/libgdx/blob/396126f3af63eb9d0d263afc59653e00e8083778/tests/gdx-tests/src/com/badlogic/gdx/tests/UITest.java