android - How to update View inflated from XML file in a SurfaceView's onDraw(Canvas canvas) method? -

so making pong game has activity sets contentview() surfaceview.

public class pong_activity extends activity {  private static final string tag = pong_activity.class.getsimplename(); static int screenwidth; static int screenheight; public view image; layoutinflater inflater; relativelayout mainview;  @override public void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     requestwindowfeature(window.feature_no_title);     getwindow().addflags(windowmanager.layoutparams.flag_fullscreen);     display screen = getwindowmanager().getdefaultdisplay();     rect rect_screen = new rect();     screen.getrectsize(rect_screen);     screenwidth = rect_screen.width();     screenheight = rect_screen.height();     log.d(tag, "the size of screen width: " + screenwidth             + "height: " + screenheight);     // set content view surfaceview (the game panel)     setcontentview(new maingamepanel(this));     log.d(tag, "surfaceview maingamepanel added"); } 

within surfaceview have overrided ondraw() , call continuously through inner thread class make graphics move. know if not repaint canvas previous position of graphics retained usally call canvas.drawcolor() rid of that. want add in image @drawables/ place in background of surfaceview , refresh when ondraw() called, not seem drawing view (background) onto canvas.

public maingamepanel(context context ) {     super(context);     getholder().addcallback(this);     // create thread game loop     thread = new gamethread(getholder(), this);     rectplayer = new player_rect(leftx,false);     otherplayer = new player_rect(rightx,true);     gameball = new ball();     inflater = (layoutinflater)context.getsystemservice(context.layout_inflater_service);     background = inflater.inflate(r.layout.basic_game_screen, null);     setfocusable(true);     log.d(tag, "maingame panel, thread created");  }      @override protected void ondraw(canvas canvas) {     //canvas.drawcolor(color.black);     background.draw(canvas);     gameball.bordercollision();     gameball.rectanglecollison(rectplayer);     gameball.rectanglecollison(otherplayer);     otherplayer.compterresponse(gameball);     if (gameball.cloneball != null) {         gameball.cloneball.draw(canvas);     }     gameball.draw(canvas);     rectplayer.draw(canvas);     otherplayer.draw(canvas);  } 

this draw() called, inner class of maingamepanel

private class gamethread extends thread { private boolean running; private surfaceholder surfaceholder; private maingamepanel gamepanel; private canvas canvas; private static final string tag = "gamethread";      public gamethread(surfaceholder holder, maingamepanel panel) {         super("gamethread");         this.surfaceholder = holder;         this.gamepanel = panel;      }      public void setrunning(boolean running) {         this.running = running;     }      @override     public void run() {         long threadruntime = 0l;         log.d(tag, "starting game loop through game thread class.");         while (running) {             canvas = null;             try {                 canvas = this.surfaceholder.lockcanvas();                 // 1 accessible 1 thread @ time                 synchronized (surfaceholder) {                     // update canvas calling surface view methods.                     this.gamepanel.ondraw(canvas);                 }              } {                 // if canvas exists reupdate drawn objects                 // canvas through                 if (canvas != null) {                     surfaceholder.unlockcanvasandpost(canvas);                 }             }             threadruntime++;         }         log.d(tag, "the thread ran " + threadruntime + "times");      }  }