当我从会议室数据库获取数据时，有时在编辑表单期间从会议室数据库获取空数据
我正在尝试确定数据库中是否存在具有某些Items的项目，但是即使我知道它在数据库中，我也一直为空。 我一直在查看“房间”查询示例，但无法解决该问题。当我尝试打印查询日志时，除了IndexOutOfBounds异常外，我在运行代码时没有看到任何错误。
存储库类
public class SectorRepository
{
private String DB_NAME = "db_foodgospel";
private SectorDatabase sectorDatabase;
public SectorRepository(Context context)
{
sectorDatabase = Room.databaseBuilder(context, SectorDatabase.class, DB_NAME)
.fallbackToDestructiveMigration().allowMainThreadQueries().build();
}
public LiveData<List<State>> getAllState()
{
return sectorDatabase.daoAccess().fetchAllStateData();
}
public LiveData<List<District>> getAllDistrict(int state_id) {
return sectorDatabase.daoAccess().fetchDistrictDataByStateId(state_id);
}
public LiveData<List<City>> getAllCityData(int state_id)
{
return sectorDatabase.daoAccess().fetchAllCityData(state_id);
}
片段类
public class AddFarmerFragment extends Fragment {
private SectorRepository objSectorRepository;
private ArrayList<State> arlStateList = new ArrayList<>();
private ArrayList<District> arlDistrictList = new ArrayList<>();
private ArrayList<City> arlCityList = new ArrayList<>();
private UserFarmer objFarmer = null;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
objSectorRepository = new SectorRepository(getActivity());
objSectorRepository.getAllState().observe(this, new Observer<List<State>>() {
@Override
public void onChanged(@Nullable List<State> states) {
arlStateList.addAll(states);
}
});
stateIdForDistrict = objFarmer.getState().getId();
objSectorRepository.getAllDistrict(stateIdForDistrict).observe(this, new Observer<List<District>>() {
@Override
public void onChanged(@Nullable List<District> districts) {
arlDistrictList.addAll(districts)
}
});
stateIdForCity = objFarmer.getState().getId();
objSectorRepository.getAllCityData(stateIdForCity).observe(this, new Observer<List<City>>() {
@Override
public void onChanged(@Nullable List<City> cities) {
arlCityList.addAll(cities);
}
});
btnNext = view.findViewById(R.id.btnNext);
btnNext.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
final FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
final AddFarmerStepThreeFragment objAddFarmerStepThreeFragment = new AddFarmerStepThreeFragment();
Bundle bundle = new Bundle();
bundle.putSerializable("FarmerEditStepTwo", objFarmer);
bundle.putSerializable("StateList", arlStateList);
bundle.putSerializable("CityList", arlCityList);
bundle.putSerializable("DistrictList", arlDistrictList);
objAddFarmerStepThreeFragment.setArguments(bundle);
fragmentTransaction.replace(R.id.frameLayout, objAddFarmerStepThreeFragment).commit();
fragmentTransaction.addToBackStack(null);
}
}
});
return view;
}
片段类
public class AddFarmerStepThreeFragment extends Fragment{
Spinner spCity, spState, spDistrict;
ArrayList<String> arlStateName = new ArrayList<>();
private ArrayList<District> arlDistrictList = new ArrayList<>();
private ArrayList<City> arlCityList = new ArrayList<>();
private ArrayList<State> arlStateList = new ArrayList<>();
int stateId, districtstateId, selectedStateId, selectedCityId, selectedDistrictId;
Button btnNext;
private SectorRepository objSectorRepository;
private UserFarmer objFarmer = null;
Boolean isEditStepTwo;
StateArrayAdapter adpState;
DistrictArrayAdapter adpDistrict;
CityArrayAdapter adpCity;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_add_farmer_step_three, container, false);
activity = (FarmerActivity) getActivity();
objSectorRepository = new SectorRepository(getActivity());
final AddFarmerAllData objAllFarmerData = (AddFarmerAllData) getArguments().getSerializable("FarmerStepTwo");
isEditStepTwo = getArguments().getBoolean("isEditStepTwo", false);
spCity = view.findViewById(R.id.spCity);
spState = view.findViewById(R.id.spState);
spDistrict = view.findViewById(R.id.spDistrict);
etAddress = view.findViewById(R.id.etAddress);
objSectorRepository.getAllState().observe(this, new Observer<List<State>>() {
@Override
public void onChanged(@Nullable List<State> states) {
if (states.size() > 0) {
arlStateList.clear();
arlStateList.addAll(states);
adpState = new StateArrayAdapter(getActivity(), R.layout.item_spinner, arlStateList);
spState.setAdapter(adpState);
if (isEditStepTwo) {
int getPosition = adpState.getPosition(new State(objFarmer.getState().getId(), objFarmer.getState().getName()));
spState.setSelection(getPosition);
}
}
}
});
spState.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
int selectedId = 0;
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
selectedId = arlStateList.get(position).getId();
arlDistrictList.clear();
arlCityList.clear();
selectedStateId = arlStateList.get(position).getId();
objSectorRepository = new SectorRepository(getActivity());
objSectorRepository.getAllDistrict(selectedId).observe(AddFarmerStepThreeFragment.this, new Observer<List<District>>() {
@Override
public void onChanged(@Nullable List<District> districts) {
arlDistrictList.addAll(districts);
spDistrict.setAdapter(new DistrictArrayAdapter(getActivity(), R.layout.item_spinner, arlDistrictList));
}
});
objSectorRepository = new SectorRepository(getActivity());
objSectorRepository.getAllCityData(selectedId).observe(AddFarmerStepThreeFragment.this, new Observer<List<City>>() {
@Override
public void onChanged(@Nullable List<City> cities) {
arlCityList.addAll(cities);
spCity.setAdapter(new CityArrayAdapter(getActivity(), R.layout.item_spinner, arlCityList));
}
});
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
spDistrict.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
selectedDistrictId = arlDistrictList.get(i).getId();
Log.d("districtid", String.valueOf(selectedDistrictId));
}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {
}
});
spCity.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
selectedCityId = arlCityList.get(i).getId();
}
@Override
public void onNothingSelected(AdapterView<?> adapterView) {
}
});
if (isEditStepTwo) {
objFarmer = (UserFarmer) getArguments().getSerializable("FarmerEditStepTwo");
arlStateList.clear();
arlStateList.addAll((ArrayList<State>) getArguments().getSerializable("StateList"));
if (objFarmer.getState() == null) {
spState.setSelection(0);
} else {
adpState = new StateArrayAdapter(getActivity(), R.layout.item_spinner, arlStateList);
if (arlStateList != null || arlStateList.size() != 0) {
spState.setAdapter(adpState);
}
int getPosition = adpState.getPosition(new State(objFarmer.getState().getId(), objFarmer.getState().getName()));
spState.setSelection(getPosition);
}
if (objFarmer.getDistrict() == null) {
spDistrict.setSelection(0);
}
else
{
spDistrict.setSelection(objFarmer.getDistrict().getId());
}
if (objFarmer.getCity() == null) {
spCity.setSelection(0);
}
else {
spCity.setSelection(objFarmer.getCity().getId());
}
}
我希望在编辑时选择州ID的地区数据基础，但是从数据库中获取空数据。