Android Open Source - BlockDrop Game Update Thread

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Back to project page BlockDrop.

License

The source code is released under:

MIT License

Java Source Code

package com.seven.segment.roadsign.blockdrop;
/*  w  w  w  .  ja va  2s . c om*/
import android.content.Context;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.Log;
import android.view.SurfaceHolder;


/**
 * @author Kolijn Wolfaardt
 * @version 0.1
 */
public class GameUpdateThread extends Thread
{

  // flag to hold game state
  private SurfaceHolder mSurfaceHolder;
  private GameSurface mGamePanel;
  private GameEngine mGameEngine;

  private long delay;
  private long sleepTime = 70;

  private Paint blackPaint;

  // State of the Game
  boolean running = true;

  private static final String TAG = GameUpdateThread.class.getSimpleName();

  public GameUpdateThread(SurfaceHolder surfaceHolder, GameSurface gamePanel,GameEngine gameEngine)
  {
    super();
    this.mSurfaceHolder = surfaceHolder;
    this.mGamePanel = gamePanel;
    this.mGameEngine = gameEngine;

    blackPaint = new Paint();
    blackPaint.setARGB(255, 0, 0, 0);
  }
  
  /** 
   * Disables updating of the game.
   */
  public void pauseThread()
  {
    this.running = false;
  }
  
  /** 
   * Enables updating of the game.
   */
  public void runThread()
  {
    this.running = true;
  }
  
  /**
   * 
   * @return true is the game is paused
   */
  public boolean isPaused()
  {
    return !running;
  }

  @Override
  /** 
   * Runs the thread. Should only be called once, when the thread is created.
   * 
   * This function updates the game, draws it, and then sleeps for a given period.
   */
  public void run()
  {
    Log.d("BLOCK","Thread Started Running");
    while (running == true)
    {
      // Measure the time before
      long beforeTime = System.nanoTime();

      //Update the Game
      mGameEngine.update();

      Canvas c = null;
      try
      {
        // lock canvas so nothing else can use it
        c = mSurfaceHolder.lockCanvas(null);
        //TODO: What happens if this returns null? How do we exit?
        if (c != null)
        {
          synchronized (mSurfaceHolder)
          {
            //Clear the screen
            c.drawRect(0, 0, c.getWidth(), c.getHeight(), blackPaint);
            
            //And render the Graphics
            mGameEngine.render(c);
          }
        }
      }
      catch (Exception e)
      {
        // TODO: Canvas Drawing Exception Handler
        Log.d(TAG,"Error in drawing" + e.toString());
      }
      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);
        }
      }

      this.sleepTime = delay - ((System.nanoTime() - beforeTime) / 1000000L);

      try
      {
        if (sleepTime > 0)
        {
          Thread.sleep(sleepTime);
        }
      }
      catch (InterruptedException ex)
      {
        // TODO: Thread sleeping Exception Handler
        Log.d(TAG, "Exited from sleeping with error: " + ex);
      }
    }
  }

  /*
   * Kudos to
   * http://blorb.tumblr.com/post/236799414/simple-java-android-game-loop for
   * writing an excellent post on the game loop
   */
}

Java Source Code List

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