Tạo file CarListFragment.java - Ví lập trình android quản lý car

//Tên gói
package com.vantinviet.adayroionline.ui.car.list;

import android.app.ProgressDialog;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.VisibleForTesting;
import androidx.databinding.DataBindingUtil;
import androidx.lifecycle.LiveData;
import androidx.lifecycle.ViewModelProviders;
import androidx.recyclerview.widget.ItemTouchHelper;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.google.android.material.snackbar.Snackbar;
import com.vantinviet.adayroionline.Config;
import com.vantinviet.adayroionline.R;
import com.vantinviet.adayroionline.binding.FragmentDataBindingComponent;
//import Fragment_Car_List
//import CarListAdapter
import com.vantinviet.adayroionline.databinding.FragmentCarListBinding;
import com.vantinviet.adayroionline.ui.car.list.adapter.CarListAdapter;
import com.vantinviet.adayroionline.ui.common.DataBoundListAdapter;
import com.vantinviet.adayroionline.ui.common.PSFragment;
import com.vantinviet.adayroionline.utils.AutoClearedValue;
import com.vantinviet.adayroionline.utils.PSDialogMsg;
import com.vantinviet.adayroionline.utils.Utils;
import com.vantinviet.adayroionline.viewmodel.car.CarViewModel;
import com.vantinviet.adayroionline.viewobject.Car;
import com.vantinviet.adayroionline.viewobject.common.Resource;
import com.vantinviet.adayroionline.viewobject.common.Status;

import java.util.List;

public class CarListFragment extends PSFragment implements DataBoundListAdapter.DiffUtilDispatchedInterface {

    private final androidx.databinding.DataBindingComponent dataBindingComponent = new FragmentDataBindingComponent(this);
    private CarViewModel carViewModel;
    private PSDialogMsg psDialogMsg;
    private List<Car> carList;
    @VisibleForTesting
    private AutoClearedValue<FragmentCarListBinding> fragmentCarListBindingAutoClearedValue;
    private AutoClearedValue<CarListAdapter> carListAdapterAutoClearedValue;
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        //set car fragment sử dụng layout fragment_car_list
        FragmentCarListBinding fragmentCarListBinding = DataBindingUtil.inflate(inflater, R.layout.fragment_car_list, container, false, dataBindingComponent);

        fragmentCarListBindingAutoClearedValue = new AutoClearedValue<>(this, fragmentCarListBinding);

        return fragmentCarListBindingAutoClearedValue.get().getRoot();

    }
    //Khởi tạo các ui
    @Override
    protected void initUIAndActions() {
        psDialogMsg = new PSDialogMsg(getActivity(), false);
        //kiểm tra khi có sự kiện scroll của carListRecyclerView
        fragmentCarListBindingAutoClearedValue.get().carListRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
            //Khi người dùng kéo xong
            @Override
            public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
                LinearLayoutManager layoutManager = (LinearLayoutManager)
                        recyclerView.getLayoutManager();

                if (layoutManager != null) {

                    int lastPosition = layoutManager
                            .findLastVisibleItemPosition();

                    if (lastPosition == carListAdapterAutoClearedValue.get().getItemCount() - 1) {

                        if (!fragmentCarListBindingAutoClearedValue.get().getLoadingMore() && !carViewModel.forceEndLoading) {

                            carViewModel.loadingDirection = Utils.LoadingDirection.bottom;

                            int limit = Config.LIST_CARS_COUNT;

                            carViewModel.start = carViewModel.start + limit;

                            carViewModel.setLoadingState(true);

                            carViewModel.setNextPageCarsObj(String.valueOf(Config.LIST_CARS_COUNT), String.valueOf(carViewModel.start));
                        }
                    }
                }
            }
        });


        fragmentCarListBindingAutoClearedValue.get().swipeRefresh.setColorSchemeColors(getResources().getColor(R.color.view__primary_line));
        fragmentCarListBindingAutoClearedValue.get().swipeRefresh.setProgressBackgroundColorSchemeColor(getResources().getColor(R.color.global__primary));
        fragmentCarListBindingAutoClearedValue.get().swipeRefresh.setOnRefreshListener(() -> {

            carViewModel.loadingDirection = Utils.LoadingDirection.top;

            // reset carViewModel.offset

            carViewModel.start = 0;

            // reset carViewModel.forceEndLoading
            carViewModel.forceEndLoading = false;

            carViewModel.setCarsObj(String.valueOf(Config.LIST_CARS_COUNT), String.valueOf(carViewModel.start));

            // update live data

        });
        fragmentCarListBindingAutoClearedValue.get().AddCarButton.setOnClickListener(v -> {
            navigationController.navigateToCarFormActivity(getActivity(),"");
        });



    }

    @Override
    protected void initViewModels() {

        carViewModel = ViewModelProviders.of(this, viewModelFactory).get(CarViewModel.class);

    }

    @Override
    protected void initAdapters() {

        CarListAdapter nvAdapter = new CarListAdapter(dataBindingComponent,car -> navigationController.navigateToCarDetailActivity/*Hiện tại hàm này chưa được xây dựng, chúng ta sẽ làm ở bước này nhấn vào đây để xem [Chú ý là bước này chúng ta sẽ làm sau nhé] */(CarListFragment.this.getActivity(), car.id), this);

        this.carListAdapterAutoClearedValue = new AutoClearedValue<>(this, nvAdapter);
        fragmentCarListBindingAutoClearedValue.get().carListRecyclerView.setAdapter(carListAdapterAutoClearedValue.get());
        new ItemTouchHelper(new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {
            @Override
            public boolean onMove(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, @NonNull RecyclerView.ViewHolder target) {
                // this method is called
                // when the item is moved.
                return false;
            }

            @Override
            public void onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int direction) {
                // this method is called when we swipe our item to right direction.
                // on below line we are getting the item at a particular position.
                Car car = carList.get(viewHolder.getAdapterPosition());

                // below line is to get the position
                // of the item at that position.
                int position = viewHolder.getAdapterPosition();
                psDialogMsg.showConfirmDialog("Bạn có chắc chăn muốn xóa không ?","Chắc chắn","Hủy");
                psDialogMsg.show();

                psDialogMsg.okButton.setOnClickListener(view -> {

                    psDialogMsg.cancel();

                    // this method is called when item is swiped.
                    // below line is to remove item from our array list.
                    carList.remove(viewHolder.getAdapterPosition());
                    // below line is to notify our item is removed from adapter.
                    carListAdapterAutoClearedValue.get().notifyItemRemoved(viewHolder.getAdapterPosition());
                    // below line is to display our snackbar with action.
                    Snackbar.make(fragmentCarListBindingAutoClearedValue.get().carListRecyclerView, car.carName, Snackbar.LENGTH_LONG).setAction("Undo", new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            // adding on click listener to our action of snack bar.
                            // below line is to add our item to array list with a position.
                            carList.add(position, car);

                            // below line is to notify item is
                            // added to our adapter class.
                            carListAdapterAutoClearedValue.get().notifyItemInserted(position);
                        }
                    }).show();
                    carViewModel.setDeleteCarObj(car.id);
                });
                psDialogMsg.cancelButton.setOnClickListener(view -> {
                    psDialogMsg.cancel();
                    carList.add(position, car);
                    carListAdapterAutoClearedValue.get().notifyItemInserted(position);
                });
            }
            // at last we are adding this
            // to our recycler view.
        }).attachToRecyclerView(fragmentCarListBindingAutoClearedValue.get().carListRecyclerView);
    }
    //Khởi tạo dữ liệu
    @Override
    protected void initData() {
        // bắt đầu lấy dữ liệu
        carViewModel.setCarsObj(String.valueOf(Config.LIST_CARS_COUNT), String.valueOf(carViewModel.start));
        //Quan sát khi có dữ liệu được lấy về
        carViewModel.getCarsData().observe(this, result -> {

            if (result != null) {
                switch (result.status) {
                    //Nếu lấy dữ liệu về thành công
                    case SUCCESS:
                        carList=result.data;
                        replaceCarList(result.data);
                        carViewModel.setLoadingState(false);
                        break;
                    //nếu vẫn đang trong quá trình tải
                    case LOADING:
                        replaceCarList(result.data);
                        break;
                    //nếu phát sinh một lỗi bất kỳ
                    case ERROR:

                        carViewModel.setLoadingState(false);
                        break;
                }
            }

        });
        //Quan sát khi người dùng kéo scroll xuống dưới
        carViewModel.getNextPageCarsData().observe(this, state -> {
            if (state != null) {
                if (state.status == Status.ERROR) {

                    carViewModel.setLoadingState(false);
                    carViewModel.forceEndLoading = true;
                }
            }
        });


        carViewModel.getLoadingState().observe(this, loadingState -> {

            fragmentCarListBindingAutoClearedValue.get().setLoadingMore(carViewModel.isLoading);

            if (loadingState != null && !loadingState) {
                fragmentCarListBindingAutoClearedValue.get().swipeRefresh.setRefreshing(false);
            }

        });
        LiveData<Resource<Boolean>> delete_car = carViewModel.getDeletedCar();
        delete_car.observe(this, status_Resource -> {
            if (status_Resource != null) {
                psDialogMsg.showSuccessDialog(getString(R.string.str_delete_car_success),"Ok");
                psDialogMsg.show();
            }
        });
    }
    //Thực hiện việc cập nhật lại dữ liệu car
    private void replaceCarList(List<Car> carList) {
        Utils.psLog("carList",carList.toString());
        this.carListAdapterAutoClearedValue.get().replace(carList);
        fragmentCarListBindingAutoClearedValue.get().executePendingBindings();
    }


    @Override
    public void onDispatched() {
        if (carViewModel.loadingDirection == Utils.LoadingDirection.top) {

            if (fragmentCarListBindingAutoClearedValue.get().carListRecyclerView != null) {

                LinearLayoutManager layoutManager = (LinearLayoutManager)
                        fragmentCarListBindingAutoClearedValue.get().carListRecyclerView.getLayoutManager();

                if (layoutManager != null) {
                    layoutManager.scrollToPosition(0);
                }
            }
        }
    }
}