Example of enter and exit called on clicked button

MyGdxGame.java

package com.mygdx.game;

import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.Color;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.Pixmap;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.graphics.g2d.TextureRegion;
import com.badlogic.gdx.math.MathUtils;
import com.badlogic.gdx.scenes.scene2d.Actor;
import com.badlogic.gdx.scenes.scene2d.InputEvent;
import com.badlogic.gdx.scenes.scene2d.Stage;
import com.badlogic.gdx.scenes.scene2d.ui.Button;
import com.badlogic.gdx.scenes.scene2d.ui.Skin;
import com.badlogic.gdx.scenes.scene2d.ui.TextButton;
import com.badlogic.gdx.scenes.scene2d.utils.ClickListener;
import com.badlogic.gdx.scenes.scene2d.utils.Drawable;
import com.badlogic.gdx.scenes.scene2d.utils.TextureRegionDrawable;

public class MyGdxGame extends ApplicationAdapter {
	private Stage stage;
	private Pixmap pixmap;
	Texture texture;

	@Override
	public void create () {
		stage = new Stage();
		Gdx.input.setInputProcessor(stage);
		pixmap = new Pixmap(2, 2, Pixmap.Format.RGBA8888);
		pixmap.setColor(Color.WHITE);
		pixmap.fill();
		texture = new Texture(pixmap);
		TextureRegionDrawable up = new TextureRegionDrawable(new TextureRegion(texture));
		Drawable down = up.tint(Color.BLUE);

		for (int i = 0; i < 2; i++) {
			Button button = new Button(up, down);
			button.setX(MathUtils.random(0, Gdx.graphics.getWidth()-100));
			button.setY(MathUtils.random(0, Gdx.graphics.getHeight()-100));
			button.setWidth(MathUtils.random(50, 100));
			button.setHeight(MathUtils.random(50, 100));
			button.addListener(enterExitListener);
			stage.addActor(button);
		}
	}

	@Override
	public void render () {
		Gdx.gl.glClearColor(0.2f, 0.2f, 0.2f, 1);
		Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
		stage.act();
		stage.draw();
	}

	@Override
	public void resize (int width, int height) {
		stage.getViewport().update(width, height, true);
	}

	@Override
	public void dispose () {
		stage.dispose();
		pixmap.dispose();
		texture.dispose();
	}

	private ClickListener enterExitListener = new ClickListener(){
		public void enter (InputEvent event, float x, float y, int pointer, Actor fromActor) {
			super.enter(event, x, y, pointer, fromActor);
			Gdx.app.log("enterExitListener", "entered ");
		}
		public void exit (InputEvent event, float x, float y, int pointer, Actor toActor) {
			super.exit(event, x, y, pointer, toActor);
			Gdx.app.log("enterExitListener", "exited ");
		}
	};
}