我正在阅读自过去几天以来的“开始Android游戏”一书。但我很难理解代码。
您可以在此处查看或下载代码: http://code.google.com/p/beginnginandroidgames2/downloads/list
我的意思是ch06-mr-mom
项目。该活动名为MrNomGame
:
public abstract class AndroidGame extends Activity implements Game {
AndroidFastRenderView renderView;
Graphics graphics;
Audio audio;
Input input;
FileIO fileIO;
Screen screen;
WakeLock wakeLock;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
boolean isLandscape = getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE;
int frameBufferWidth = isLandscape ? 480 : 320;
int frameBufferHeight = isLandscape ? 320 : 480;
Bitmap frameBuffer = Bitmap.createBitmap(frameBufferWidth,
frameBufferHeight, Config.RGB_565);
float scaleX = (float) frameBufferWidth
/ getWindowManager().getDefaultDisplay().getWidth();
float scaleY = (float) frameBufferHeight
/ getWindowManager().getDefaultDisplay().getHeight();
renderView = new AndroidFastRenderView(this, frameBuffer);
graphics = new AndroidGraphics(getAssets(), frameBuffer);
fileIO = new AndroidFileIO(this);
audio = new AndroidAudio(this);
input = new AndroidInput(this, renderView, scaleX, scaleY);
screen = getStartScreen();
setContentView(renderView);
PowerManager powerManager = (PowerManager) getSystemService(Context.POWER_SERVICE);
wakeLock = powerManager.newWakeLock(PowerManager.FULL_WAKE_LOCK, "GLGame");
}
@Override
public void onResume() {
super.onResume();
wakeLock.acquire();
screen.resume();
renderView.resume();
}
@Override
public void onPause() {
super.onPause();
wakeLock.release();
renderView.pause();
screen.pause();
if (isFinishing())
screen.dispose();
}
public Input getInput() {
return input;
}
public FileIO getFileIO() {
return fileIO;
}
public Graphics getGraphics() {
return graphics;
}
public Audio getAudio() {
return audio;
}
public void setScreen(Screen screen) {
if (screen == null)
throw new IllegalArgumentException("Screen must not be null");
this.screen.pause();
this.screen.dispose();
screen.resume();
screen.update(0);
this.screen = screen;
}
public Screen getCurrentScreen() {
return screen;
}
}
该类实现了接口Game
:
package com.badlogic.androidgames.framework;
public interface Game {
public Input getInput();
public FileIO getFileIO();
public Graphics getGraphics();
public Audio getAudio();
public void setScreen(Screen screen);
public Screen getCurrentScreen();
public Screen getStartScreen();
}
我的第一个问题是:我错过了接口getStartScreen()
的方法Game
的实现。通常我必须实现接口的所有方法。
无论如何,现在onCreate
正在运行。在这一行:
screen = getStartScreen();
该程序返回到原始类MrNomGame
,其中方法getStartScreen()
为变量LoadingScreen
提供screen
的对象。班级LoadingScreen
:
public class LoadingScreen extends Screen {
public LoadingScreen(Game game) {
super(game);
}
public void update(float deltaTime) {
Graphics g = game.getGraphics();
Assets.background = g.newPixmap("background.png", PixmapFormat.RGB565);
Assets.logo = g.newPixmap("logo.png", PixmapFormat.ARGB4444);
Assets.mainMenu = g.newPixmap("mainmenu.png", PixmapFormat.ARGB4444);
Assets.buttons = g.newPixmap("buttons.png", PixmapFormat.ARGB4444);
Assets.help1 = g.newPixmap("help1.png", PixmapFormat.ARGB4444);
Assets.help2 = g.newPixmap("help2.png", PixmapFormat.ARGB4444);
Assets.help3 = g.newPixmap("help3.png", PixmapFormat.ARGB4444);
Assets.numbers = g.newPixmap("numbers.png", PixmapFormat.ARGB4444);
Assets.ready = g.newPixmap("ready.png", PixmapFormat.ARGB4444);
Assets.pause = g.newPixmap("pausemenu.png", PixmapFormat.ARGB4444);
Assets.gameOver = g.newPixmap("gameover.png", PixmapFormat.ARGB4444);
Assets.headUp = g.newPixmap("headup.png", PixmapFormat.ARGB4444);
Assets.headLeft = g.newPixmap("headleft.png", PixmapFormat.ARGB4444);
Assets.headDown = g.newPixmap("headdown.png", PixmapFormat.ARGB4444);
Assets.headRight = g.newPixmap("headright.png", PixmapFormat.ARGB4444);
Assets.tail = g.newPixmap("tail.png", PixmapFormat.ARGB4444);
Assets.stain1 = g.newPixmap("stain1.png", PixmapFormat.ARGB4444);
Assets.stain2 = g.newPixmap("stain2.png", PixmapFormat.ARGB4444);
Assets.stain3 = g.newPixmap("stain3.png", PixmapFormat.ARGB4444);
Assets.click = game.getAudio().newSound("click.ogg");
Assets.eat = game.getAudio().newSound("eat.ogg");
Assets.bitten = game.getAudio().newSound("bitten.ogg");
Settings.load(game.getFileIO());
game.setScreen(new MainMenuScreen(game));
}
public void present(float deltaTime) {
}
public void pause() {
}
public void resume() {
}
public void dispose() {
}
}
班级Screen
:
public abstract class Screen {
protected final Game game;
public Screen(Game game) {
this.game = game;
}
public abstract void update(float deltaTime);
public abstract void present(float deltaTime);
public abstract void pause();
public abstract void resume();
public abstract void dispose();
}
经过一段时间后,onCreate()
方法结束。但是在调试模式下,我的手机屏幕已经黑了,黑了。好像是程序在循环中。我可以随心所欲地按F6。但是当我恢复主菜单时会显示。如果您查看代码,您会看到主菜单会使用update()
的{{1}}方法调用。
我的重要问题是: loadingScreen
方法完成后会发生什么以及程序如何进入onCreate()
的{{1}}方法?
我知道这是很多代码。但是对我来说理解它会非常有用。
答案 0 :(得分:4)
关于第一个问题:AndroidGame
是一个抽象类。这意味着只要其中一个扩展Game
的类执行此操作,就不必实现AndroidGame
的所有方法。从代码中可以看出,这是在MrNomGame
:
public class MrNomGame extends AndroidGame {
public Screen getStartScreen() {
return new LoadingScreen(this);
}
}
现在提出一个大问题:
在onCreate
中,创建了一个渲染器:
renderView = new AndroidFastRenderView(this, frameBuffer);
如果您查看该类,您会看到onResume
创建一个运行以下代码的新线程:
public void run() {
Rect dstRect = new Rect();
long startTime = System.nanoTime();
while(running) {
if(!holder.getSurface().isValid())
continue;
float deltaTime = (System.nanoTime()-startTime) / 1000000000.0f;
startTime = System.nanoTime();
game.getCurrentScreen().update(deltaTime);
game.getCurrentScreen().present(deltaTime);
Canvas canvas = holder.lockCanvas();
canvas.getClipBounds(dstRect);
canvas.drawBitmap(framebuffer, null, dstRect, null);
holder.unlockCanvasAndPost(canvas);
}
}
因此,它会在当前屏幕上重复调用update
,这是LoadingScreen
的实例。