onResume does not work on fragment change

Question

there are two fragments tabs.ill explain it in brief,in the first fragment tab I'm setting my image (grid view)as favourite and displaying that favourite image in second fragment tab using the room database...the problem is the favourite image is getting added after restarting the app.can anyone what should I do.i have tried on resume but it is not working when I switch the tab. everytime if I want to see the recent added image as favourites I have to restart the app...can anyone help?

firstfragment:

public class FirstFragment extends Fragment {
private GridViewAdapter adapter;
private GridView mGridView;
//ProgressBar myProgressBar;
ProgressDialog progressDialog;
ViewPager viewPager;
private static final String HI = "http://mapi.trycatchtech.com/v1/stylish_hair_cut_for_pubg/stylish_hair_cut_for_pubg_list";
public List<RetroPhoto> product_lists=new ArrayList<>();

private JsonArrayRequest request;
private RequestQueue requestQueue;
public static FavoriteDatabase favoriteDatabase;


private void populateGridView(List<RetroPhoto> spacecraftList) {
    //mGridView = findViewById(R.id.mGridView);
    mGridView = getView().findViewById(R.id.mGridView);
    adapter = new GridViewAdapter(getContext(), spacecraftList);
    mGridView.setAdapter(adapter);
}

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_first, container, false);
    return rootView;
}

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    favoriteDatabase = Room.databaseBuilder(getContext(), FavoriteDatabase.class, "myfavdb").allowMainThreadQueries().build();

    //  myProgressBar= getView().findViewById(R.id.myProgressBar);
    progressDialog = new ProgressDialog(getContext());
    progressDialog.setMessage("Loading....");
    progressDialog.show();

    /*Create handle for the RetrofitInstance interface*/
    GetDataService myAPIService = RetrofitClientInstance.getRetrofitInstance().create(GetDataService.class);

    Call<List<RetroPhoto>> call = myAPIService.getAllPhotos();
    call.enqueue(new Callback<List<RetroPhoto>>() {

        @Override
        public void onResponse(Call<List<RetroPhoto>> call, Response<List<RetroPhoto>> response) {
            //        myProgressBar.setVisibility(View.GONE);
            progressDialog.dismiss();
            populateGridView(response.body());
            getData();
        }




        @Override
        public void onFailure(Call<List<RetroPhoto>> call, Throwable throwable) {
            //        myProgressBar.setVisibility(View.GONE);
            progressDialog.dismiss();
            Log.d("url", "error");
        }
    });}private void getData()
  {

request = new JsonArrayRequest(HI, new com.android.volley.Response.Listener<JSONArray>() {
    @Override
    public void onResponse(JSONArray response) {
        JSONObject ob;

        for (int i = 0; i <response.length(); i++) {
            try {

                ob = response.getJSONObject(i);
                RetroPhoto pr = new RetroPhoto(ob.getInt("id"),
                        ob.getString("image"),
                        ob.getString("thumb_image"));

                product_lists.add(pr);
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
        setupData(product_lists);
    }
}, new com.android.volley.Response.ErrorListener() {
    @Override
    public void onErrorResponse(VolleyError error) {
        Toast.makeText(getContext(), "errrrrrrrrrr", Toast.LENGTH_LONG).show();

    }
});
requestQueue = Volley.newRequestQueue(getContext());
  requestQueue.add(request);
}
private void setupData(List<RetroPhoto> product_lists) {
    adapter = new GridViewAdapter(getContext(), product_lists);
    mGridView.setAdapter(adapter);
}}

second fragment:

public class SecondFragment extends Fragment  {
private RecyclerView rv;
private FavoriteAdapter adapter;
public static FavoriteDatabase favoriteDatabase;
ProgressDialog progressDialog;



@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.activity_favourites,container, false);
    return rootView;
}



@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);


    rv=(RecyclerView)getView().findViewById(R.id.rec);
    rv.setHasFixedSize(true);
    rv.setLayoutManager(new LinearLayoutManager(getContext()));



}
public void getFavData() {

    List<FavoriteList> favoriteLists=FirstFragment.favoriteDatabase.favoriteDao().getFavoriteData();
    adapter=new FavoriteAdapter(favoriteLists,getContext());
    rv.setAdapter(adapter);
}

@Override
public void onResume() {
    this.getFavData();
    super.onResume();
}}

Answer 1

Where are you putting these two Fragments, in an Activity or a Fragment? Are you using ViewPager for tabs?

I am suspecting the second fragment is instantiated before you select a favorite image, that's why it never gets updated. If this is the case, calling getFavData() inside onResume() won't help.

One of the approach is to call SecondFragment.getFavData() in your main fragment/activity after favorite image is set.

Try adding this in second fragment:

@Override
public void setUserVisibleHint(boolean isVisibleToUser) {
    super.setUserVisibleHint(isVisibleToUser);
    if(isVisibleToUser) {
        getFavData();
    }
}

Answer 2

As you mentioned you are using viewpager to put the two fragments, you need to call getFavData in onResume() and setUserVisibleHint(boolean isVisibleToUser). onResume() is called in the first time when the fragment is created, and the setUserVisibleHint() is called when the the page in viewpager is shown or hidden.