image - How to set wallpaper permanently in android -

i creating app set image wallpaper. using following code fix image in every screen. code working fine. image fit properly. have 1 problem if play game , home screen or restart device size of wallpaper zoom. want stop this. want image size fit on first time when set wallpaper android app.

here's code-

    @override     public void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.full_image);         face = typeface.createfromasset(getassets(), "fonts/abeakrg.ttf");         intent = getintent();         position = i.getextras().getint("id");                 full = (linearlayout) findviewbyid(r.id.full);         btn = (button)findviewbyid(r.id.btn);         btn.settypeface(face);         btn.setonclicklistener(new button.onclicklistener(){         @override         public void onclick(view arg0) {               displaymetrics metrics = new displaymetrics();               getwindowmanager().getdefaultdisplay().getmetrics(metrics);              int height = metrics.heightpixels;               int width = metrics.widthpixels;              bitmap tempbitmap = bitmapfactory.decoderesource(getresources(), mthumbid[position]);              bitmap bitmap = bitmap.createscaledbitmap(tempbitmap,width,height, true);              wallpapermanager wallpapermanager = wallpapermanager.getinstance(fullimageactivity.this);               wallpapermanager.setwallpaperoffsetsteps(1, 1);              wallpapermanager.suggestdesireddimensions(width, height);              try {                wallpapermanager.setbitmap(bitmap);                toast.maketext(getapplicationcontext(), "done", toast.length_short).show();                } catch (ioexception e) {                e.printstacktrace();              }         }});         changebackground();         activityswipedetector activityswipedetector = new activityswipedetector(this);         full.setontouchlistener(activityswipedetector);     }        private void changebackground(){         full.setbackgroundresource(mthumbid[position]);    } 

thanks in advance.

here code segment working that

the mainactivity.java code

the bootreceiver.java setting wallpaper after boot completed..code

and manifest.xml setting permissions..code

thanks