Android 2d physics engine box2d usage Simple example _android

The example in this article describes the box2d usage of the 2d physical engine under Android. Share to everyone for your reference. Specifically as follows:

When the program is running, it needs to load the jbox2d library, which can be downloaded at the following address (using the library Jbox2d-2.0.1-library-only.jar without the render part):

http://sourceforge.net/projects/jbox2d/

Package com.test;
Import Org.jbox2d.collision.AABB;
Import Org.jbox2d.collision.CircleDef;
Import Org.jbox2d.collision.PolygonDef;
Import ORG.JBOX2D.COMMON.VEC2;
Import Org.jbox2d.dynamics.Body;
Import Org.jbox2d.dynamics.BodyDef;
Import Org.jbox2d.dynamics.World;
Import android.app.Activity;
Import Android.content.Context;
Import Android.graphics.Canvas;
Import Android.graphics.Color;
Import Android.graphics.Paint;
Import Android.os.Bundle;
Import Android.os.Handler;
Import Android.view.View;
Import Android.view.Window;
Import Android.view.WindowManager;
 public class Mybox2d extends activity {private final static int RATE = 10;//screen to real world proportions 10px:1m;
 Private AABB Worldaabb;
 Create a world that manages collisions with private worlds;
 private float Timestep = 1/60;//analog frequency private int iterations = 10;//iteration, the simulation is approximately accurate, but the lower the performance of the private body body,body2,body3;
 Private MyView MyView;
  Private Handler Mhandler;
    public void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate); RequestwiNdowfeature (Window.feature_no_title); GetWindow (). SetFlags (Windowmanager.layoutparams. Flag_fullscreen, Windowmanager.layoutparams.
    Flag_fullscreen);
     
    Worldaabb = new AABB (); The upper and lower bounds, with the top left of the screen as the origin, if the created Rigidbody reaches the edge of the screen, it stops the analog worldAABB.lowerBound.set ( -100.0f,-100.0f); WorldAABB.upperBound.set (100.
    0f, 100.0f);
    Note that the real-world units used here are Vec2 gravity = new VEC2 (0.0f,10.0f);
    Boolean dosleep = true;  
    Worlds = New World (Worldaabb, Gravity, dosleep);//Create a worldwide Createbox (160, 470, 160, true);
    CreateBox1 (160, 160, false);
    Createcircle (160, 100, 10);
    CreateCircle1 (150, 60, 10);
    Timestep = 1.0f/60.0f;
    iterations = 10;
    MyView = new MyView (this);
    Setcontentview (MyView);
    Mhandler = new Handler ();
  Mhandler.post (update);
       Private Runnable update = new Runnable () {public void run () {World.step (timestep, iterations);//Start simulation
       VEC2 position = Body.getposition ();
VEC2 Position1 = Body2.getposition ();       VEC2 position2 = Body3.getposition ();
       Myview.x=position.x*rate;
       Myview.y=position.y*rate;
       Myview.x1=position1.x*rate;
       Myview.y1=position1.y*rate;
       Myview.x2=position2.x*rate;
        Myview.y2=position2.y*rate;
        Myview.update ();
    Mhandler.postdelayed (update, (long) timestep*1000);
  }
  }; public void Createbox (float x,float y,float half_width,float half_height,boolean isstatic) {polygondef shape = new Poly
   Gondef ();
   if (isstatic) {shape.density = 0;}
   else{shape.density = 2.0f;}
   Shape.friction = 0.8f;
   Shape.restitution = 0.3f;
   Shape.setasbox (Half_width/rate, half_height/rate);
   Bodydef bodydef = new Bodydef ();
   BodyDef.position.set (X/rate, y/rate);
   Body body1= world.createbody (bodydef);
   Body1.createshape (Shape);
  Body1.setmassfromshapes ();
   public void createcircle (float x,float y,float radius) {circledef shape = new Circledef ();
   shape.density = 7;
   Shape.friction = 0.2f; Shape.radius =Radius/rate;
   Bodydef bodydef = new Bodydef ();
   BodyDef.position.set (X/rate, y/rate);
   Body2 = World.createbody (bodydef);
   Body2.createshape (Shape);
  Body2.setmassfromshapes ();
   public void CreateCircle1 (float x,float y,float radius) {circledef shape = new Circledef ();
   shape.density = 7;
   Shape.friction = 0.2f;
   Shape.radius = radius/rate;
   Bodydef bodydef = new Bodydef ();
   BodyDef.position.set (X/rate, y/rate);
   Body3 = World.createbody (bodydef);
   Body3.createshape (Shape);
  Body3.setmassfromshapes ();  } public void CreateBox1 (float x,float y,float half_width,float half_height,boolean isstatic) {polygondef shape = new
   Polygondef ();
   if (isstatic) {shape.density = 0;}
   else{shape.density = 2.0f;}
   Shape.friction = 0.3f;
   Shape.setasbox (Half_width/rate, half_height/rate);
   Bodydef bodydef = new Bodydef ();
   BodyDef.position.set (X/rate, y/rate);
   body= world.createbody (BODYDEF);
   Body.createshape (Shape);
  Body.setmassfromshapes (); }
  Class MyView extends view{Canvas Canvas;
   public float x=160,y=150;
   public float x1=160,y1=100;
 public float x2=150,y2=60;
 Public MyView {Super (context);
  public void Drawbox (float x,float y) {Paint mpaint = new Paint ();
  Mpaint.setantialias (TRUE);
  Mpaint.setcolor (color.red);
 Canvas.drawrect (x-160, y-10, x+160, y+10, Mpaint);
  public void Drawground () {Paint mpaint = new Paint ();
  Mpaint.setantialias (TRUE);
  Mpaint.setcolor (Color.Blue);
 Canvas.drawrect (0, 460, mpaint);
  public void drawcircle (float x1,float y1) {Paint mpaint = new Paint ();
  Mpaint.setantialias (TRUE);
  Mpaint.setcolor (Color.green);
 Canvas.drawcircle (x1, y1, mpaint);
 public void Update () {postinvalidate ();
  } protected void OnDraw (Canvas Canvas) {Super.ondraw (Canvas);
  This.canvas = Canvas;
  Drawground ();
  Drawbox (x, y);
  Drawcircle (x1, y1);
 Drawcircle (x2, y2);

 }
 }
}

I hope this article will help you with your Android program.