[英]retrieving the current user data from firestore and use it in another query
我有兩個用戶管理員和教職員工。 管理員用戶可以添加和檢索教師數據。 管理員的數據庫格式是管理員數據庫,教員數據庫是教員數據庫。基本上我希望管理員訪問其部門的教員數據。示例-擁有 MCA 部門的管理員只能訪問 MCA 部門的教員數據。
public class userfaculty extends Fragment {
FirebaseFirestore fStore;
private FirebaseAuth fAuth;
RecyclerView mFirestoreList;
FirestorePagingAdapter adapter;
String admindept,adminid;
Query query;
private UserfacultyViewModel mViewModel;
public static userfaculty newInstance() {
return new userfaculty();
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
FloatingActionButton fab = view.findViewById(R.id.fabuserfaculty);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(getContext(), AdminAddUserFaculty.class));
}
});
fStore=FirebaseFirestore.getInstance();
fAuth=FirebaseAuth.getInstance();
mFirestoreList=view.findViewById(R.id.RVuserfaculty);
//get current user department
adminid=fAuth.getCurrentUser().getUid();
fStore.collection("Admin").document(adminid).get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
@Override
public void onSuccess(DocumentSnapshot documentSnapshot) {
admindept= documentSnapshot.getString("Department");
Log.i("Admindept",admindept);
}
});
'這里我想使用檢索到的當前用戶部門來訪問數據'
//divider decoration
DividerItemDecoration dividerItemDecoration=new
DividerItemDecoration(getContext(),DividerItemDecoration.VERTICAL);
dividerItemDecoration.setDrawable(getResources().getDrawable(R.drawable.recyclerview_divider));
mFirestoreList.addItemDecoration(dividerItemDecoration);
//Query
query = fStore.collection("Faculty").doument("admindept").collection("Teachers");
PagedList.Config config=new PagedList.Config.Builder()
.setInitialLoadSizeHint(10)
.setPageSize(3)
.build();
//RecyclerOptions
FirestorePagingOptions<FacultyModelA> options=new FirestorePagingOptions.Builder<FacultyModelA>()
.setLifecycleOwner(this)
.setQuery(query, config, new SnapshotParser<FacultyModelA>() {
@NonNull
@Override
public FacultyModelA parseSnapshot(@NonNull DocumentSnapshot snapshot) {
FacultyModelA facultyModelA=snapshot.toObject(FacultyModelA.class);
return facultyModelA;
}
})
.build();
adapter=new FirestorePagingAdapter<FacultyModelA, FacultyViewHolder>(options) {
@NonNull
@Override
public FacultyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View v=LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_single_admin_faculty,parent,false);
return new FacultyViewHolder(v);
}
@Override
protected void onBindViewHolder(@NonNull FacultyViewHolder holder, int position, @NonNull FacultyModelA model) {
holder.list_name.setText(model.getName());
}
@Override
protected void onLoadingStateChanged(@NonNull LoadingState state) {
super.onLoadingStateChanged(state);
switch (state){
case LOADING_INITIAL:
Log.d("PAGING_LOG","All inintial data");
break;
case LOADING_MORE:
Log.d("PAGING_LOG","All next page");
break;
case FINISHED:
Log.d("PAGING_LOG","All data loaded");
break;
case ERROR:
Log.d("PAGING_LOG","Error Loading Data");
break;
case LOADED:
Log.d("PAGING_LOG","Total Item Loaded: "+getItemCount());
break;
}
}
};
mFirestoreList.setHasFixedSize(true);
mFirestoreList.setLayoutManager(new LinearLayoutManager(getContext()));
mFirestoreList.setAdapter(adapter);
}
class FacultyViewHolder extends RecyclerView.ViewHolder{
private TextView list_name;
public FacultyViewHolder(@NonNull View itemView) {
super(itemView);
list_name=itemView.findViewById(R.id.list_fname);
}
}
}
'但是在這一行,我得到了一個 null 指針異常'
query = fStore.collection("Faculty").doument(admindept).collection("Teachers");
我應該做些什么改變......提前謝謝你。
您在代碼中的文檔名稱是“admindept”,但在屏幕截圖中是“MCA”。 修復它,你可能會讓它工作。
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