set image for gridview after if statement

so i have a gridview and i'm trying to set gridview's items image after a if statement in gridview's onItemClick... in below code i tried to explain my question in backslashs:

 GridView grid;
    String[] web = {
            " ",
            " ",
            " ",
            " ",
            " "

    } ;
    int[] imageId = {
            R.drawable.example,
            R.drawable.example,
            R.drawable.example,
            R.drawable.example,
            R.drawable.example
    };



    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.first_frag, container, false);

        CustomGrid adapter = new CustomGrid(getActivity(), web, imageId);
        grid=(GridView) v.findViewById(R.id.grid);
        grid.setAdapter(adapter);
        grid.setOnItemClickListener(new AdapterView.OnItemClickListener() {


            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                                    int position, long id) {
                switch(position){

                    case 0:
                        if (level_1_isdone == true){
                            //set a image
                           }
                        else {
                            //set some other image 
                           }

                    case 1:
                    case 2:
                    case 3:
                    case 4:
                }
            }
        });

        return v;
    }