How to update nested data in fire-base database android

问题

Nested data in firebase database snap pic Hi guys, I have store data in a real-time database which contains nested children and I had stored this data through using push feature in order to avoid overwriting issue but now the problem I do not know how to fetch particular data which I already highlighted in the snap image. unfortunately, I am struggling in how I can fetch that nested data in order to perform editing or deleting functions. the following are the addUser class and the part of fetching the data into RecyclerView

public class AddUserAppointment {

   private String StartBusinse;
   private String StartBusinseTime ;
    private String EndBusinseTime ;
   private String startFirstAppoint ;
   private String endSecondAppointment ;
   private String AppointmentStuts;
  // private String AppointmentKey;  

    public AddUserAppointment() {
        ////empty
    }

    public AddUserAppointment(String startBusinse, String startBusinseTime, String endBusinseTime, String startFirstAppoint, String endSecondAppointment, String appointmentStuts) {
        StartBusinse = startBusinse;
        StartBusinseTime = startBusinseTime;
        EndBusinseTime = endBusinseTime;
        this.startFirstAppoint = startFirstAppoint;
        this.endSecondAppointment = endSecondAppointment;
        AppointmentStuts = appointmentStuts;
    }

    public String getStartBusinse() {
        return StartBusinse;
    }

    public void setStartBusinse(String startBusinse) {
        StartBusinse = startBusinse;
    }

    public String getStartBusinseTime() {
        return StartBusinseTime;
    }

    public void setStartBusinseTime(String startBusinseTime) {
        StartBusinseTime = startBusinseTime;
    }

    public String getEndBusinseTime() {
        return EndBusinseTime;
    }

    public void setEndBusinseTime(String endBusinseTime) {
        EndBusinseTime = endBusinseTime;
    }

    public String getStartFirstAppoint() {
        return startFirstAppoint;
    }

    public void setStartFirstAppoint(String startFirstAppoint) {
        this.startFirstAppoint = startFirstAppoint;
    }

    public String getEndSecondAppointment() {
        return endSecondAppointment;
    }

    public void setEndSecondAppointment(String endSecondAppointment) {
        this.endSecondAppointment = endSecondAppointment;
    }

    public String getAppointmentStuts() {
        return AppointmentStuts;
    }

    public void setAppointmentStuts(String appointmentStuts) {
        AppointmentStuts = appointmentStuts;
    }

fetch data class

public class ListAppointmentCustomerClass extends AppCompatActivity {
    private DatabaseReference AppointmentRef,SeconDref;
    private FirebaseAuth mAuth;
    private String PostKey;
    private RecyclerView ListAllApointment;
    private String pushkey;
    private Button Book,Cancel;
    private String AppointmentKey;
    private String keyId;
    private String m_Text = "";
    private boolean AppointmentCondation = true;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_list_appointment_customer_class);
        //pushkey = AppointmentRef.getKey();

        PostKey = getIntent().getExtras().get("Postkey").toString();

        AppointmentRef = FirebaseDatabase.getInstance().getReference().child("Appointments").child(PostKey);

        ///

        ////
        ListAllApointment = (RecyclerView)findViewById(R.id.ListAppointmentView);
        LinearLayoutManager customerLayoutManager = new LinearLayoutManager(this);
        customerLayoutManager.setReverseLayout(true);
        customerLayoutManager.setStackFromEnd(true);
        ListAllApointment.setLayoutManager(customerLayoutManager);
        //TODO:All the methods shoud be list here
        DisplayuploadedAppointment();
    }

    public static class HolderClass extends RecyclerView.ViewHolder{
        View mView;
        Button bookAppointment , CancelAppoinment;

        public HolderClass(View itemView) {
            super(itemView);
            mView = itemView;

            bookAppointment = (Button)mView.findViewById(R.id.BookAnppointments);

        }

        public void setStartFirstAppoint(String startFirstAppoint){
          TextView StartAppointment = (TextView)mView.findViewById(R.id.StartAppointmet);
          StartAppointment.setText(startFirstAppoint);
        }
        public void setEndSecondAppointment(String endSecondAppointment){
            TextView EndAppointment = (TextView)mView.findViewById(R.id.EndAppointment);
            EndAppointment.setText(endSecondAppointment);

        }
        public void setAppointmentStuts(String appointmentStuts){
            TextView appointment = (TextView)mView.findViewById(R.id.BookingStatus);
            appointment.setText(appointmentStuts);
        }



    }

    private void DisplayuploadedAppointment() {
        FirebaseRecyclerAdapter<AddUserAppointment,HolderClass >AppointmentRecyclerAdapter =
                new FirebaseRecyclerAdapter<AddUserAppointment, HolderClass>
                        (
                                AddUserAppointment.class,
                                R.layout.listallapointment,
                                HolderClass.class,
                                AppointmentRef
                        ) {
                    @Override
                    protected void populateViewHolder(HolderClass viewHolder, AddUserAppointment model, final int position)
                    {


                        viewHolder.setStartFirstAppoint(model.getStartFirstAppoint());
                        viewHolder.setEndSecondAppointment(model.getEndSecondAppointment());
                        viewHolder.setAppointmentStuts(model.getAppointmentStuts());
                        viewHolder.mView.setTag(position);
                        viewHolder.bookAppointment.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View view) {
                                final DatabaseReference mDatabase = FirebaseDatabase.getInstance().getReference().child("Appointments").child(PostKey);

                                final String id = getRef(position).getKey();
                                mDatabase.child(id).addValueEventListener(new ValueEventListener() {
                                    @Override
                                    public void onDataChange(DataSnapshot dataSnapshot) {
                                        for (DataSnapshot snapshot : dataSnapshot.getChildren()){
                                            System.out.println("Id"+id);
                                            String bookingCondation = dataSnapshot.child("appointmentStuts").getValue().toString() ;
                                            HashMap hashMap = new HashMap<>();
                                            hashMap.put("appointmentStuts","Boooked");

                                           System.out.println("Postkey"+PostKey);
                                           mDatabase.updateChildren(hashMap).addOnCompleteListener(new OnCompleteListener() {
                                               @Override
                                               public void onComplete(@NonNull Task task) {

                                               }
                                           });



//                                            String key = snapshot.getKey().toString();
//                                            System.out.println(key);


//                                            String bookingCondation = dataSnapshot.child("appointmentStuts").getValue().toString() ;
//                                            System.out.println("Appointment Status "+bookingCondation);

                                           // Log.e("Appointment : " , "" + appointmentStuts+ap.getStartFirstAppoint()+key);


                                        }

                                    }

                                    @Override
                                    public void onCancelled(DatabaseError databaseError) {

                                    }
                                });

                            }
                        });


                    }
                };
        ListAllApointment.setAdapter(AppointmentRecyclerAdapter);



    }



    }

回答1:

You can iterate through the users to get their data like this:

  DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference().child("Appointments").addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            Iterator<DataSnapshot> dataSnapshots = dataSnapshot.getChildren().iterator();

            while (dataSnapshots.hasNext()) {
                DataSnapshot dataSnapshotChild = dataSnapshots.next();
                AddUserAppointment user = dataSnapshotChild.getValue(AddUserAppointment.class);
            }
        }
        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

来源：https://stackoverflow.com/questions/52156206/how-to-update-nested-data-in-fire-base-database-android