runnable - Android update UI every 2 seconds -

i have been searching around , tried out solutions day nothing worked, decide post code here , hope can give me help, thanks!

i have fragment extends listfragment.

the list has 4 items; bottom three, set pictures , text in getview() method in private listadapter class. first one, want continuously change picture. have array, promotion_image_array , of bitmap contains 3 bitmap use source first item. following code of getview() , screenshot of got right now:

    @override     public view getview(int position, view convertview, viewgroup parent) {         final viewholder holder;         view myview = convertview;          system.out.println("in getview");          if (myview == null) {             myview = inflater.inflate(r.layout.home_category_item, null);             holder = new viewholder();             holder.item_image= (imageview)myview.findviewbyid(r.id.item_image);             holder.res_name = (textview)myview.findviewbyid(r.id.res_name);               if(position == 0){                 holder.res_name.setvisibility(view.gone);                 promotion_image_view = holder.item_image;                 system.out.println("position == 0");             }             else if(position == 1) {                 holder.res_name.settext("food");                 holder.item_image.setbackgroundresource(r.drawable.restaurant_icon);                 system.out.println("position == 1");             }             else if(position == 2) {                 holder.res_name.settext("shop");                 holder.item_image.setbackgroundresource(r.drawable.shop_icon);                 system.out.println("position == 2");             }             else if(position == 3) {                 holder.res_name.settext("groupon");                 holder.item_image.setbackgroundresource(r.drawable.groupon_icon);                 system.out.println("position == 3");             }             myview.settag(holder);         }         else {             // view recycled, no need inflate             holder = (viewholder) myview.gettag();         }          return myview;     } }

tried use handler , runnable continuously update image of first item in oncreate() method of fragment. have static variable promotion_image_view declared @ top of fragment , use line of code actual imageview of first item in getview() method:(from code piece above)

promotion_image_view = holder.item_image;

and tried set promotion_image_view's background in runnable's run() method, following code of runnable , handler in oncreate():

      counter = 0;        mhandler = new myhandler(this);        runnable = new runnable() {           @override           public void run() {               mhandler.postdelayed(runnable,3000);                // repeatedly display 3 promotion images               bitmap[] promotion_image_array = my_global_variables.city_config_object.config_promotion_image_array;               bitmapdrawable ob = new bitmapdrawable(my_resources, promotion_image_array[counter]);               if(promotion_image_view != null) {                   promotion_image_view.setbackground(ob);                   system.out.println("promotion_image_view != null");               }               system.out.format("in run: counter = %d%n", counter);               counter++;               if(counter == 3) counter = 0;           }       };        runnable.run();

both promotion_image_view != null ,

in run: counter = %d%n, counter

got printed out properly(continuously printed out @ constant rate) , counter's value correct, too.(0,1,2,0,1,2,0.....). picture did not change @ all.

i appreciate help, thank you!!

******************************* after read answers --- first edit *******************************

thanks people answered, tried notifydatasetchanged() method, still not working; image not changed, printout looks correct.

the following revised code:

getview() method:

   @override     public view getview(int position, view convertview, viewgroup parent) {         final viewholder holder;         view myview = convertview;          if (myview == null) {             myview = inflater.inflate(r.layout.home_category_item, null);             holder = new viewholder();             holder.item_image= (imageview)myview.findviewbyid(r.id.item_image);             holder.res_name = (textview)myview.findviewbyid(r.id.res_name);              if(position == 0){                 holder.res_name.setvisibility(view.gone);                  bitmap[] promotion_image_array = my_global_variables.city_config_object.config_promotion_image_array;                 bitmapdrawable ob = new bitmapdrawable(my_resources, promotion_image_array[counter]);                 holder.item_image.setbackground(ob);                  system.out.format("in run: counter = %d%n", counter);                 counter++;                 if(counter == 3) counter = 0;                  system.out.println("in getview: position == 0");             }             else if(position == 1) {                 holder.res_name.settext("food");                 holder.item_image.setbackgroundresource(r.drawable.restaurant_icon);                 system.out.println("position == 1");             }             else if(position == 2) {                 holder.res_name.settext("shop");                 holder.item_image.setbackgroundresource(r.drawable.shop_icon);                 system.out.println("position == 2");             }             else if(position == 3) {                 holder.res_name.settext("groupon");                 holder.item_image.setbackgroundresource(r.drawable.groupon_icon);                 system.out.println("position == 3");             }             myview.settag(holder);         }         else {             // view recycled, no need inflate             holder = (viewholder) myview.gettag();         }          return myview;     } }

handler , runnable:

      counter = 0;        mhandler = new myhandler(this);        runnable = new runnable() {           @override           public void run() {               mhandler.postdelayed(runnable, 3000);               adapter.notifydatasetchanged();           }       };        runnable.run();

and following print out looks correct me:

i/system.out﹕ in run: counter = 0