NikitiJ

class QRCodesScannerActivity : AppCompatActivity() {

    private val TAG = "CameraPermission"
    private val CAMERA_REQUEST_CODE = 101

    private lateinit var barcodeDetector: BarcodeDetector
    private lateinit var cameraSource: CameraSource

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

NikitiJ

//Расчёт количества столбцов относительно размеров экрана и ориентации
    public static int getGridColumnsCount(Context context){
        boolean landscape = context.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE;

        DisplayMetrics displayMetrics = context.getResources().getDisplayMetrics();
        float hi=displayMetrics.heightPixels/displayMetrics.xdpi;
        float wi=displayMetrics.widthPixels/displayMetrics.ydpi;
        float screenWidthInch  = landscape ? Math.max(wi, hi) : Math.min(wi, hi);
        float screenWidthCm = screenWidthInch * 2.54f;
        int columns = (int)(screenWidthCm/2);

NikitiJ

public class ChatPageTabFragmentsAdapter extends FragmentPagerAdapter {

	private List<Fragment> fragmentList = new ArrayList<>();
	private ManagerModel[] managers;

	public ChatPageTabFragmentsAdapter(FragmentManager fm, ManagerModel[] managerModels) {
		super(fm);
		this.managers = managerModels;
	}

NikitiJ

public class MessageItemAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

	private List<MessageModel> messages;
	private String managerPhotoUrl;

	public MessageItemAdapter(List<MessageModel> messages) {
		this.messages = messages;
	}

	public void setManagerPhotoUrl(String url) {

NikitiJ

public class ChatFragment extends Fragment {
	private static final String ARG_MANAGER = "manager";
	private List<MessageModel> messages = new ArrayList<>();
	private MessageItemAdapter messageItemAdapter = new MessageItemAdapter(messages);
	private Unbinder unbinder;

	@BindView(R.id.progressbar_loading_container)
	FrameLayout progressbarLoadingView;

	@BindView(R.id.recyclerView_messagesContainer)

NikitiJ

public class ChatActivity extends AppCompatActivity {
	private ActivityCommonUtils activityCommonUtils = new ActivityCommonUtils(this);
	private ManagerModel[] managerModels;

	@BindView(R.id.tabLayout_container)
	TabLayout tabsContainer;

	@BindView(R.id.viewPager_tabsPager)
	ViewPager fragmentPager;

NikitiJ

*************** Архитектура асинхронные запросы в Андроид
	
	//Имеются общие классы для запросов :
	
  // обертка над любыми запросами
	public class RequestWrapper <T> {
    public String apiVersion = "2.0";
    public String accessToken;
    public T requestData;