Android中Box2d初涉小例子

package com.nono.demo.box2d; import org.jbox2d.collision.AABB; import org.jbox2d.common.Vec2; import org.jbox2d.dynamics.Body; import org.jbox2d.dynamics.World; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Paint.Style; import android.view.MotionEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; /** * 游戏视图 * @author Nono * */ public class MainGameView extends SurfaceView implements SurfaceHolder.Callback, Runnable{ private Context mContext; private SurfaceHolder holder; private Paint paint; private Canvas canvas; private World world; private Bitmap bitmapBg; private Bitmap bmpStone; private Thread thread; private boolean flag = false; public MainGameView(Context context) { super(context); mContext = context; this.setKeepScreenOn(true);//保持屏幕常亮 holder = this.getHolder();//获取控制器 holder.addCallback(this);//添加监听 paint = new Paint();//实例化画笔 paint.setStyle(Style.FILL_AND_STROKE); paint.setColor(Color.BLACK); paint.setAntiAlias(true); this.setFocusable(true); this.setFocusableInTouchMode(true); //创建一个物理世界 AABB aabb = new AABB(); aabb.lowerBound = new Vec2(-100, -100); aabb.upperBound = new Vec2(100, 100); Vec2 gravity = new Vec2(0, 10); world = new World(aabb, gravity, true); } public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) { bitmapBg = BitmapFactory.decodeResource(getResources(), R.drawable.background); bmpStone = BitmapFactory.decodeResource(getResources(), R.drawable.tile1); WorldBodyFactory.createStone(world, getWidth()/2, getHeight()/2, bmpStone.getWidth(), bmpStone.getHeight(), 0, 1.0f, bmpStone);//创建一个小石头 WorldBodyFactory.createPolygon(world, 0, getHeight()-5,getWidth() , 30, 0, 0); thread = new Thread(this);//地面 flag = true; thread.start(); } public void surfaceCreated(SurfaceHolder arg0) { // TODO Auto-generated method stub } public void surfaceDestroyed(SurfaceHolder arg0) { flag = false; } /** * 绘图 */ private void draw() { try{ canvas = holder.lockCanvas(); canvas.drawColor(Color.BLACK);//清屏 //绘制背景 canvas.drawBitmap(bitmapBg, 0, 0, paint); //遍历绘制Body Body body = world.getBodyList(); for(int i = 1; i < world.getBodyCount(); i++){ if ((body.m_userData) instanceof MyRect) { MyRect rect = (MyRect) (body.m_userData); rect.drawRect(canvas, paint); }if ((body.m_userData) instanceof MyStone) { MyStone title = (MyStone) (body.m_userData); title.drawStone(canvas, paint); } body = body.m_next; } }catch(Exception e){ }finally{ try { if (canvas != null) holder.unlockCanvasAndPost(canvas); } catch (Exception e2) { } } } /** * 逻辑 */ private void logic() { world.step(Constant.stepTime, Constant.iteraTions); ///遍历Body，进行Body与图形之间的传递数据 Body body = world.getBodyList(); for (int i = 1; i < world.getBodyCount(); i++) { //判定m_userData中的数据是否为MyRect实例 if ((body.m_userData) instanceof MyRect) { MyRect rect = (MyRect) (body.m_userData); rect.setX(body.getPosition().x * Constant.RATE - rect.getW() / 2); rect.setY(body.getPosition().y *Constant.RATE - rect.getH() / 2); rect.setAngle((float) (body.getAngle() * 180 / Math.PI)); } else if ((body.m_userData) instanceof MyStone) { //判定m_userData中的数据是否为MyTile实例 MyStone tile = (MyStone) (body.m_userData); tile.setX(body.getPosition().x * Constant.RATE - tile.getW() / 2); tile.setY(body.getPosition().y * Constant.RATE- tile.getH() / 2); tile.setAngle((float) (body.getAngle() * 180 / Math.PI)); } body = body.m_next; } conut++; } public void run() { while (flag) { logic(); draw(); try { Thread.sleep((long)Constant.stepTime * 1000); } catch (Exception ex) { } } } private int conut = 0; @Override public boolean onTouchEvent(MotionEvent event) { if(event.getAction() == MotionEvent.ACTION_DOWN &&conut > 100){ WorldBodyFactory.createStone(world, getWidth()/2, bmpStone.getHeight(), bmpStone.getWidth(), bmpStone.getHeight(), 0f, 0.5f, bmpStone); conut = 0; } return super.onTouchEvent(event); } }