LunarLander and Snake 游戏更新线程总结

snake:是通过send和receive MSG方法来实现视图的跟新。invalidate（）
sudokuv：是也是通过invalidate跟新视图。由于没有自更新。所以视图变化发生在按键事件

jetboy:类似lunarlander
LunarLander:是通过线程在RUN方法中while(TRUE)中一直执行dodraw方法。其中它需要取得屏幕的canvas

1.extends view。这个方法所有的绘制都在onDraw()函数里进行，通过调用invalidate()通知系统调用onDraw()重绘屏幕，但是如果是在非UI线程中请求重绘就不一样了，具体怎么做大家自己去看看相关的东西。我没有看过，因为一般游戏开发我们会选择下一种方法。
2.extends SurfaceView,这是游戏开发最常用的方式，应该说如果你的游戏需要不停的更新图像，比如有帧动画的播放等等，那么就采用这种方式吧。
surfaceview的方式下你需要 implements SurfaceHolder.Callback
class SurfaceViewCore extends SurfaceView implements SurfaceHolder.Callback

LunarLander

class LunarView extends SurfaceView implements SurfaceHolder.Callback {
   
    public LunarView(Context context, AttributeSet attrs) {
        super(context, attrs);

        // register our interest in hearing about changes to our surface
        SurfaceHolder holder = getHolder();
        holder.addCallback(this);

        // create thread only; it's started in surfaceCreated()
        thread = new LunarThread(holder, context, new Handler() {
            @Override
            public void handleMessage(Message m) {
                mStatusText.setVisibility(m.getData().getInt("viz"));
                mStatusText.setText(m.getData().getString("text"));
            }
        });

        setFocusable(true); // make sure we get key events
    }

    @Override
    public void onWindowFocusChanged(boolean hasWindowFocus) {
        if (!hasWindowFocus) thread.pause();
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // start the thread here so that we don't busy-wait in run()
        // waiting for the surface to be created
        thread.setRunning(true);
        thread.start();
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // we have to tell thread to shut down & wait for it to finish, or else
        // it might touch the Surface after we return and explode
        boolean retry = true;
        thread.setRunning(false);
        while (retry) {
            try {
                thread.join();
                retry = false;
            } catch (InterruptedException e) {
            }
        }
    }

 class LunarThread extends Thread {
     
        public LunarThread(SurfaceHolder surfaceHolder, Context context,
                Handler handler) {
            // get handles to some important objects
            mSurfaceHolder = surfaceHolder;
            mHandler = handler;
            mContext = context;

             }

        public void run() {
            while (mRun) {
                Canvas c = null;
                try {
                    c = mSurfaceHolder.lockCanvas(null);
                    synchronized (mSurfaceHolder) {
                        if (mMode == STATE_RUNNING) updatePhysics();
                        doDraw(c);
                    }
                } finally {
                    // do this in a finally so that if an exception is thrown
                    // during the above, we don't leave the Surface in an
                    // inconsistent state
                    if (c != null) {
                        mSurfaceHolder.unlockCanvasAndPost(c);
                    }
                }
            }
        }

        public void setState(int mode, CharSequence message) {
            synchronized (mSurfaceHolder) {
                mMode = mode;

                if (mMode == STATE_RUNNING) {
                    Message msg = mHandler.obtainMessage();
                    Bundle b = new Bundle();
                    b.putString("text", "");
                    b.putInt("viz", View.INVISIBLE);
                    msg.setData(b);
                    mHandler.sendMessage(msg);
                } else {

                    if (message != null) {
                        str = message + "\n" + str;
                    }

                    if (mMode == STATE_LOSE) mWinsInARow = 0;

                    Message msg = mHandler.obtainMessage();
                    Bundle b = new Bundle();
                    b.putString("text", str.toString());
                    b.putInt("viz", View.VISIBLE);
                    msg.setData(b);
                    mHandler.sendMessage(msg);
                }
            }
        }

        private void doDraw(Canvas canvas) {
     
        }
    }

}

Snake

public class SnakeView extends TileView {

    private static final Random RNG = new Random();

    private RefreshHandler mRedrawHandler = new RefreshHandler();

    class RefreshHandler extends Handler {

        @Override
        public void handleMessage(Message msg) {
            SnakeView.this.update();
            SnakeView.this.invalidate();
        }

        public void sleep(long delayMillis) {
        	this.removeMessages(0);
            sendMessageDelayed(obtainMessage(0), delayMillis);
        }
    };

    public SnakeView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initSnakeView();
   }

    public SnakeView(Context context, AttributeSet attrs, int defStyle) {
    	super(context, attrs, defStyle);
    	initSnakeView();
    }

    private void initSnakeView() {
        setFocusable(true);

    }
    

    private void initNewGame() {
      
    }

    public void update() {
            mRedrawHandler.sleep(mMoveDelay);
        }

    }

    
}