Android编程之View简单学习示例

public class Activity01 extends Activity { 
  private static final String TAG = "mThread"; 
  private static final int REFRESH = 0x000001; 
  private GameView mGameView = null; 
  @Override 
  public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    this.mGameView = new GameView(this); 
    mGameView.x = 320.0f; 
    mGameView.y = 120.0f; 
    setContentView(mGameView); 
    new Thread(new GameThread()).start(); 
  } 
  Handler myHandler = new Handler() { 
    @Override 
    public void handleMessage(Message msg) { 
      switch (msg.what) { 
      case Activity01.REFRESH: 
        mGameView.invalidate();   // repaint View 
        break; 
      } 
      super.handleMessage(msg); 
    } 
  }; 
  class GameThread implements Runnable { 
    @Override 
    public void run() { 
      while (!Thread.currentThread().isInterrupted()) { 
        Message message = new Message(); 
        message.what = Activity01.REFRESH; 
        Activity01.this.myHandler.sendMessage(message); 
        try { 
          Thread.sleep(1000); 
        } catch (InterruptedException e) { 
          Thread.currentThread().interrupt(); 
        } 
      } 
    } 
  } 
  @Override 
  public boolean onTouchEvent(MotionEvent event) { 
    if(event.getAction() == MotionEvent.ACTION_DOWN){ 
      mGameView.x = event.getX(); 
      mGameView.y = event.getY(); 
    } 
    return true; 
  } 
  @Override 
  public boolean onKeyDown(int keyCode, KeyEvent event) { 
    if(keyCode == KeyEvent.KEYCODE_BACK){ 
      this.finish(); 
    } 
    return true; 
  } 
}

public class GameView extends View { 
  int count = 0; 
  float x = 0, y = 0; 
  public GameView(Context context) { 
    super(context); 
  } 
  public void onDraw(Canvas canvas) { 
    if (count < 100) { 
      count++; 
    } else { 
      count = 0; 
    } 
    Paint mPaint = new Paint(); 
    switch (count % 4) { 
    case 0: 
      mPaint.setColor(Color.BLUE); 
      break; 
    case 1: 
      mPaint.setColor(Color.GREEN); 
      break; 
    case 2: 
      mPaint.setColor(Color.RED); 
      break; 
    case 3: 
      mPaint.setColor(Color.YELLOW); 
      break; 
    default: 
      mPaint.setColor(Color.WHITE); 
      break; 
    } 
    canvas.drawRect(x - 40, y - 20, x + 40, y + 20, mPaint); 
  } 
}