Java tutorial
/* * This file is part of Jump Don't Die * Copyright (C) 2015 Dani Rodrguez <danirod@outlook.com> * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package es.danirod.jddprototype.game; import com.badlogic.gdx.Gdx; import com.badlogic.gdx.graphics.GL20; import com.badlogic.gdx.graphics.Texture; import com.badlogic.gdx.scenes.scene2d.Actor; import com.badlogic.gdx.scenes.scene2d.Stage; import com.badlogic.gdx.scenes.scene2d.ui.Image; import com.badlogic.gdx.scenes.scene2d.ui.Skin; import com.badlogic.gdx.scenes.scene2d.ui.TextButton; import com.badlogic.gdx.scenes.scene2d.utils.ChangeListener; import com.badlogic.gdx.utils.viewport.FitViewport; /** * This is the screen that you see when you enter the game. It has a button for playing the game. * When you press this button, you go to the game screen so that you can start to play. This * screen was done by copying the code from GameOverScreen. All the cool comments have been * copy-pasted. */ public class MenuScreen extends BaseScreen { /** The stage where all the buttons are added. */ private Stage stage; /** The skin that we use to set the style of the buttons. */ private Skin skin; /** The logo image you see on top of the screen. */ private Image logo; /** The play button you use to jump to the game screen. */ private TextButton play, credits; public MenuScreen(final MainGame game) { super(game); // Create a new stage, as usual. stage = new Stage(new FitViewport(640, 360)); // Load the skin file. The skin file contains information about the skins. It can be // passed to any widget in Scene2D UI to set the style. It just works, amazing. skin = new Skin(Gdx.files.internal("skin/uiskin.json")); // For instance, here you see that I create a new button by telling the label of the // button as well as the skin file. The background image for the button is in the skin // file. play = new TextButton("Play", skin); credits = new TextButton("Credits", skin); // Also, create an image. Images are actors that only display some texture. Useful if you // want to display a texture in a Scene2D based screen but you don't want to rewrite code. logo = new Image(game.getManager().get("logo.png", Texture.class)); // Add capture listeners. Capture listeners have one method, changed, that is executed // when the button is pressed or when the user interacts somehow with the widget. They are // cool because they let you execute some code when you press them. play.addCaptureListener(new ChangeListener() { @Override public void changed(ChangeEvent event, Actor actor) { // Take me to the game screen! game.setScreen(game.gameScreen); } }); credits.addCaptureListener(new ChangeListener() { @Override public void changed(ChangeEvent event, Actor actor) { game.setScreen(game.creditsScreen); } }); // Now I position things on screen. Sorry for making this the hardest part of this screen. // I position things on the screen so that they look centered. This is why I make the // buttons the same size. logo.setPosition(440 - logo.getWidth() / 2, 320 - logo.getHeight()); play.setSize(200, 80); credits.setSize(200, 80); play.setPosition(40, 140); credits.setPosition(40, 40); // Do not forget to add actors to the stage or we wouldn't see anything. stage.addActor(play); stage.addActor(logo); stage.addActor(credits); } @Override public void show() { // Now this is important. If you want to be able to click the button, you have to make // the Input system handle input using this Stage. Stages are also InputProcessors. By // making the Stage the default input processor for this game, it is now possible to // click on buttons and even to type on input fields. Gdx.input.setInputProcessor(stage); } @Override public void hide() { // When the screen is no more visible, you have to remember to unset the input processor. // Otherwise, input might act weird, because even if you aren't using this screen, you are // still using the stage for handling input. Gdx.input.setInputProcessor(null); } @Override public void dispose() { // Dispose assets. stage.dispose(); skin.dispose(); } @Override public void render(float delta) { Gdx.gl.glClearColor(0.2f, 0.3f, 0.5f, 1f); Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); stage.act(); stage.draw(); } }