invalidate（）不会导致onDraw（）调用

Question

我正在开发一个简单的游戏引擎，并且看到了invalidate（）问题。基本上，当我尝试使（）来自任何地方的视图无效但默认的Activity方法如果无法调用onDraw（）。有什么想法吗？

public class GameActivity extends Activity 
{
    //Name for my app
    String sTag = "CloneOut";

    //Variable to point to my view
    View myView;

    //Variable controlling the running of the game
    boolean bRunning = true;

    //Fixed framerate variables
    long desiredFramerate = 1;
    long targetTimeMillis;

    //Creates a new MusicManager object to handle all music
    MusicManager mp = new MusicManager(this);

    //Creates a new SoundEffectManager object to handle all sound effects
    SoundEffectManager sp = new SoundEffectManager(this);

    //Create new int variables to hold SoundEffectManager sound ids
    //int iBeer;

    //Create an array of bitmaps to store all the actors in the game
    Bitmap[] actor = new Bitmap[10];

    //Automatically called when an activity begins
    @SuppressLint("NewApi")
    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);

        //Critical line that sets teh view of this activity to BitmapView and
        //   thus BitmapView.draw is called to repaint the view
        setContentView(new BitmapView(this));

        // Show the Up button in the action bar.
        setupActionBar();

        myView = findViewById(android.R.id.content);
    }

    /**
     * Set up the {@link android.app.ActionBar}, if the API is available.
     */
    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    private void setupActionBar() 
    {
        //Action bar only exists in API 11+ so check before displaying
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            getActionBar().setDisplayHomeAsUpEnabled(true);
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) 
    {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.game, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) 
    {
        switch (item.getItemId())
        {
            case android.R.id.home:
                // This ID represents the Home or Up button. In the case of this
                // activity, the Up button is shown. Use NavUtils to allow users
                // to navigate up one level in the application structure. For
                // more details, see the Navigation pattern on Android Design:
                //
                // http://developer.android.com/design/patterns/navigation.html#up-vs-back
                //
                NavUtils.navigateUpFromSameTask(this);
                return true;
        }
        return super.onOptionsItemSelected(item);
    }

    class BitmapView extends View 
    {
        public BitmapView(Context context) 
        {
            super(context);
        }

        @Override
        public void onDraw(Canvas canvas) 
        {
            //Writes an informational message to the LogCat window
            Log.i(sTag,"Drawing");

            //Draw the background first
            canvas.drawColor(Color.BLACK);

            //Draw all the actors in the game
            canvas.drawBitmap(actor[0], 500, 100, null);
        }
    }

    //-----------------------------------------------------------------------------------------
    //Game Engine Code Start
    //-----------------------------------------------------------------------------------------

    //The following methods run automatically in this order
    //      onCreate() - Call immediately on starting an activity
    //      onStart()
    //      onResume() - Called when the activity starts interacting with the user
    public void onResume()
    {
        super.onResume();

        //Populate the first actor with the paddle
        actor[0] = BitmapFactory.decodeResource(getResources(), R.drawable.paddle);

        //Calculate the time at which to render the next frame
        targetTimeMillis = System.currentTimeMillis() + (1000 / desiredFramerate); 

        //Start the game running
        GameLoop();
    }

    public void GameLoop()
    {
        while (bRunning)
        {
            CheckFramerate();
        }
    }

    public void CheckFramerate()
    {
        if (System.currentTimeMillis() > targetTimeMillis)
        {
            //Calculate the time at which to render the next frame
            targetTimeMillis = System.currentTimeMillis() + (1000L / desiredFramerate); 

            //Writes an informational message to the LogCat window
            Log.i(sTag,"Renderframe");

            RenderFrame();
        }
    }

    //Invalidates the entire view and thus forces a redraw of the screen
    public void RenderFrame()
    {
        //Writes an informational message to the LogCat window
        Log.i(sTag,"Inside Renderframe");

        myView.invalidate();

    }
}