AndEngine的第一个程序HelloWorld

AndEngine的环境搭建好后，只运行Samples是远远不够的，要想真正了解如何使用这个框架，还是需要自己动手写写代码。

先从简单的HelloWorld开始。

目标：使用一张图片作为背景，并在屏幕中央显示“Hello World !”文字。

1.新建一个Android工程，设置工程属性，让工程引用AndEngine工程。

2.让工程的主Activity继承SimpleBaseGameActivity类。并实现基类中的几个方法：

[java]
public EngineOptions onCreateEngineOptions();
public void onCreateResources();
public Scene onCreateScene();
这个类的全部代码如下：
[java]
package com.example.testandeng1;

import org.andengine.engine.camera.Camera;
import org.andengine.engine.options.EngineOptions;
import org.andengine.engine.options.ScreenOrientation;
import org.andengine.engine.options.resolutionpolicy.RatioResolutionPolicy;
import org.andengine.entity.Entity;
import org.andengine.entity.scene.Scene;
import org.andengine.entity.sprite.Sprite;
import org.andengine.entity.text.Text;
import org.andengine.opengl.font.Font;
import org.andengine.opengl.font.FontFactory;
import org.andengine.opengl.texture.TextureOptions;
import org.andengine.opengl.texture.atlas.bitmap.BitmapTextureAtlas;
import org.andengine.opengl.texture.atlas.bitmap.BitmapTextureAtlasTextureRegionFactory;
import org.andengine.opengl.texture.region.ITextureRegion;
import org.andengine.ui.activity.SimpleBaseGameActivity;

import android.graphics.Color;
import android.opengl.GLES20;

public class MainActivity extends SimpleBaseGameActivity {
    public static final int CAMERA_WIDTH = 800;
    public static final int CAMERA_HEIGHT = 480;

    private static final int LAYER_COUNT = 2;

    private static final int LAYER_BACKGROUND = 0;
    private static final int LAYER_TEXT = LAYER_BACKGROUND + 1;

    private Scene mScene;

    private Font mFont;
    private BitmapTextureAtlas mBackgroundTexture;
    private ITextureRegion mBackgroundTextureRegion;

    private Text mHelloText;

    public EngineOptions onCreateEngineOptions() {
        Camera mCamera = new Camera(0, 0, CAMERA_WIDTH, CAMERA_HEIGHT);
        final EngineOptions engineOptions = new EngineOptions(true,
                ScreenOrientation.LANDSCAPE_FIXED, new RatioResolutionPolicy(
                        CAMERA_WIDTH, CAMERA_HEIGHT), mCamera);
        return engineOptions;
    }

    @Override
    public void onCreateResources(){
        /* Load the font we are going to use. */
        FontFactory.setAssetBasePath("font/");
        this.mFont = FontFactory.createFromAsset(this.getFontManager(),
                this.getTextureManager(), 512, 512, TextureOptions.BILINEAR,
                this.getAssets(), "GOTHIC.TTF", 32, true, Color.WHITE);
        this.mFont.load();

        BitmapTextureAtlasTextureRegionFactory.setAssetBasePath("img/");
        /* Load all the textures this game needs. */
        this.mBackgroundTexture = new BitmapTextureAtlas(
                this.getTextureManager(), 800, 480);
        this.mBackgroundTextureRegion = BitmapTextureAtlasTextureRegionFactory
                .createFromAsset(this.mBackgroundTexture, this, "android.png",
                        0, 0);
        this.mBackgroundTexture.load();
    }

    @Override
    public Scene onCreateScene(){
        this.mScene = new Scene();
        for (int i = 0; i < LAYER_COUNT; i++) {
            this.mScene.attachChild(new Entity());
        }

        /* No background color needed as we have a fullscreen background sprite. */
        this.mScene.setBackgroundEnabled(false);
        this.mScene.getChildByIndex(LAYER_BACKGROUND).attachChild(
                new Sprite(0, 0, this.mBackgroundTextureRegion, this
                        .getVertexBufferObjectManager()));

        this.mHelloText=new Text(CAMERA_WIDTH/2 - 80, CAMERA_HEIGHT/2 - 16, this.mFont, "Hello World !", this.getVertexBufferObjectManager());
        this.mHelloText.setBlendFunction(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE_MINUS_SRC_ALPHA);
        this.mHelloText.setAlpha(0.6f);
        this.mScene.getChildByIndex(LAYER_TEXT).attachChild(this.mHelloText);

        return this.mScene;
    }

}

补充：软件开发 , Java ,