Android Open Source - pong-android Game View

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From Project

Back to project page pong-android.

License

The source code is released under:

MIT License

Java Source Code

package me.zamecnik.android.pong;
//  w w  w .  j av a2 s  .  c om
import android.content.Context;
import android.graphics.Canvas;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public abstract class GameView extends SurfaceView implements
  SurfaceHolder.Callback {

  static final String LOG_TAG = GameView.class.getSimpleName();

  private static final float MAX_FPS = 60;
  private static final float MIN_DT = 1000.0f / MAX_FPS;

  private Thread drawingThread;
  private final SurfaceHolder surfaceHolder;
  private FpsCounter fpsCounter;

  /** time since the start of the game in milliseconds */
  private long time;

  private float timeDelta;

  public GameView(Context context) {
    super(context);

    surfaceHolder = getHolder();
    surfaceHolder.addCallback(this);
  }

  private void update() {
    long now = System.currentTimeMillis();
    timeDelta = 0.001f * (time > 0 ? now - time : 0);
    if (timeDelta != 0 && fpsCounter != null) {
      fpsCounter.updateFps(1.0 / timeDelta);
    }
    time = now;

    onUpdate();
  }

  protected abstract void onUpdate();

  protected abstract void onRender(Canvas canvas);

  @Override
  public void surfaceChanged(SurfaceHolder holder, int format, int width,
    int height) {
  }

  @Override
  public void surfaceCreated(SurfaceHolder holder) {
    drawingThread = new Thread(new Runnable() {
      public void run() {
        while (!Thread.currentThread().isInterrupted()) {
          update();
          Canvas canvas = null;
          try {
            canvas = surfaceHolder.lockCanvas();
            if (canvas != null) {
              onRender(canvas);
            }
          } finally {
            if (canvas != null) {
              surfaceHolder.unlockCanvasAndPost(canvas);
            }
          }

          long now = System.currentTimeMillis();
          float sleepTime = (time - now) + MIN_DT;
          if (sleepTime > 0) {
            try {
              Thread.sleep((long) sleepTime);
            } catch (InterruptedException e) {
              Log.i(LOG_TAG, "interrupted");
            }
          }
        }
      }
    });
    drawingThread.start();
  }

  @Override
  public void surfaceDestroyed(SurfaceHolder holder) {
    if (null != drawingThread) {
      drawingThread.interrupt();
    }
  }

  public void pause() {
    // TODO: better resolve stopping the game thread
    surfaceDestroyed(getHolder());
  }

  public void setFpsCounter(FpsCounter fpsCounter) {
    this.fpsCounter = fpsCounter;
  }

  protected long getTime() {
    return time;
  }

  protected float getTimeDelta() {
    return timeDelta;
  }

}

Java Source Code List

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