item.setIcon not work

[Naguchennai]

item.setIcon not work any help?

 mSearchView.setOnMenuItemClickListener(new FloatingSearchView.OnMenuItemClickListener() {
        @Override
        public void onActionMenuItemSelected(MenuItem item) {


            if(gridorlist.equals("list")){
                SharedPreferences.Editor editor = getSharedPreferences("GRIDLIST", MODE_PRIVATE).edit();
                editor.putString("gridorlist", "grid");
                editor.apply();

                gridorlist ="grid";
                refreshview();

                if(item.getItemId() == R.id.action_grid) {
                    item.setIcon(ContextCompat.getDrawable(MainActivity.this, R.drawable.ic_grid));
                }

            }else{
                SharedPreferences.Editor editor = getSharedPreferences("GRIDLIST", MODE_PRIVATE).edit();
                editor.putString("gridorlist", "list");
                editor.apply();

                gridorlist ="list";
                refreshview();
                if(item.getItemId() == R.id.action_grid) {
                    item.setIcon(ContextCompat.getDrawable(MainActivity.this, R.drawable.ic_list));
                }
            }

        }
    });