Input.Java

// Method untuk populate/ambil data dari db
private void setDataOltAll() {
        RestApi restApi = RetroFit.getInstanceRetrofit();
        Call<MOlt> responseCall = restApi.getDataOltAll();

        responseCall.enqueue(new Callback<MOlt>() {
            @Override
            public void onResponse(@NonNull Call<MOlt> call, @NonNull Response<MOlt> response) {
                if (response.isSuccessful()) {
                    List<DataOlt> listOltId = response.body().getDataOlt();
                    List<String> listJenis = new ArrayList<String>();

            // Inisialisasi nilai ke data yang di populate
                    for (int i = 0; i < listOltId.size(); i++) {
                        listJenis.add(listOltId.get(i).getNamaOlt());
                    }

                    ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_spinner_item, listJenis);
                    arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                    namaOlt.setAdapter(arrayAdapter);
                } else {
                    Toast.makeText(getApplicationContext(), getString(R.string.error_msg2), Toast.LENGTH_LONG).show();
                }
            }

            @Override
            public void onFailure(@NonNull Call<MOlt> call, @NonNull Throwable t) {
                Toast.makeText(getApplicationContext(), getString(R.string.error_connection), Toast.LENGTH_LONG).show();
            }
        });
    }

    // Method untuk listen on click dari yang dipilih, nilai yang dipilih ditampung di strOlt
    private void spinnerListener() {
        namaOlt.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> adapterView, View view, int position, long l) {
                TextView txtColor = (TextView) view;
                strOlt = adapterView.getItemAtPosition(position).toString();
                txtColor.setTextColor(getResources().getColor(R.color.black));
            }

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

            }
        });
    }