spinners.java

    private void loadSpinners() {
        dialog = ProgressDialog.show(AddVisitActivity.this, "", getResources().getString(R.string.loading), true);


        WebService.getService().getLocations().enqueue(new Callback<LocationListResponse>() {
            @Override
            public void onResponse(Call<LocationListResponse> call, Response<LocationListResponse> response) {

                countries = response.body().getCountry();
                cities = response.body().getCity();
                categories = response.body().getLandmarkCategory();
                landmarks = response.body().getLandmark();


                LocationListResponse.Country header = new LocationListResponse.Country();
                header.setEnName(AddVisitActivity.this.getResources().getString(R.string.countryh));
                countries.add(0, header);
                spinnerCountry.setAdapter(new ArrayAdapter<>(AddVisitActivity.this, android.R.layout.simple_list_item_1, countries));
                spinnerCountry.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                    @Override
                    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                        LocationListResponse.Country country = countries.get(position);
                        int cid = country.getOId();
                        List<LocationListResponse.City> newcities = getCitiesofCountry(cid, cities);
                        spinnerCities.setAdapter(new ArrayAdapter<>(AddVisitActivity.this, android.R.layout.simple_list_item_1, newcities));
                    }

                    @Override
                    public void onNothingSelected(AdapterView<?> parent) {

                    }
                });

                LocationListResponse.LandmarkCategory header2 = new LocationListResponse.LandmarkCategory();
                header2.setEnName(AddVisitActivity.this.getResources().getString(R.string.categoryh));
                categories.add(0, header2);
                spinnerLandmarkCategory.setAdapter(new ArrayAdapter<>(AddVisitActivity.this, android.R.layout.simple_list_item_1, categories));
                spinnerLandmarkCategory.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                    @Override
                    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                        LocationListResponse.LandmarkCategory landmarkCategory = categories.get(position);
                        int catid = landmarkCategory.getOId();
                        List<LocationListResponse.Landmark> newLandMarks = getLandMarksofCategory(catid, landmarks);
                        spinnerLandmark.setAdapter(new ArrayAdapter<>(AddVisitActivity.this, android.R.layout.simple_list_item_1, newLandMarks));

                    }

                    @Override
                    public void onNothingSelected(AdapterView<?> parent) {

                    }
                });


                dialog.dismiss();
            }

            @Override
            public void onFailure(Call<LocationListResponse> call, Throwable t) {
                dialog.dismiss();
            }
        });

    }


    private List<LocationListResponse.City> getCitiesofCountry(int countryID, List<LocationListResponse.City> sourcCities) {
        List<LocationListResponse.City> citiesofc = new ArrayList<>();
        for (int i = 0; i < sourcCities.size(); i++) {
            LocationListResponse.City current = sourcCities.get(i);
            if (current.getCountryId() == countryID) {
                citiesofc.add(current);
            }
        }
        LocationListResponse.City header = new LocationListResponse.City();
        header.setEnName(AddVisitActivity.this.getResources().getString(R.string.city));
        citiesofc.add(0, header);
        return citiesofc;

    }


    private List<LocationListResponse.Landmark> getLandMarksofCategory(int categoryID, List<LocationListResponse.Landmark> sourcLandmarks) {
        List<LocationListResponse.Landmark> landmarkofc = new ArrayList<>();
        for (int i = 0; i < sourcLandmarks.size(); i++) {
            LocationListResponse.Landmark current = sourcLandmarks.get(i);
            if (current.getCategoryId() == categoryID) {
                landmarkofc.add(current);
            }
        }
        LocationListResponse.Landmark header = new LocationListResponse.Landmark();
        header.setEnName(AddVisitActivity.this.getResources().getString(R.string.landmarkheader));
        landmarkofc.add(0, header);
        return landmarkofc;

    }