CODEWITHSUNDEEP
javaandroidfirebase
Hashaam Khurshid
Hashaam Khurshid

Reputation: 184

Firebase - (DataSnapshot with multiple child nodes user unique key ) -Null Object Refrence

I have number of Medicines corresponding to each patient unique key. i am facing trouble to retrieve all of medicine data of the patient Here is my database structure. 

  {
      "Medicine" : {
        "-LnRyr-3szcVYVtr_d4m" : {
          "Med1" : {
            "dosage" : "1+1+1",
            "medname" : "Panadol",
            "time" : "After Every Meal"
          },
          "Med2" : {
            "Mmedname" : "Raisik",
            "med2dosage" : "1+1+1",
            "med2time" : "after every meal 1 week"
          }
        }
      }
    }

Code 

 databaseReference = FirebaseDatabase.getInstance().getReference("Medidine");
        databaseReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                for (DataSnapshot requestSnapshot: dataSnapshot.getChildren()) {
                    DataSnapshot ds = requestSnapshot.child("Med1");
                    for (DataSnapshot medicinesnapshot: ds.getChildren()) {
                        String MedicineName = medicinesnapshot.child("medname").getValue(String.class);
                        String MedDosage = medicinesnapshot.child("dosage").getValue(String.class);
                        String medtime = medicinesnapshot.child("time").getValue(String.class);
                        marray.add(MedicineName+MedDosage+medtime);
                    }

                    }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });

Upvotes: 1

Views: 110

Answers (1)

Jignesh Mayani
Jignesh Mayani

Reputation: 7193

For a patient with patientId=-LnRyr-3szcVYVtr_d4m;

then you can get all medicines related to that patient like this

String patientId="-LnRyr-3szcVYVtr_d4m";

FirebaseDatabase.getInstance().getReference().child("Medicine").child(patientId).addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                if (dataSnapshot.exists()) {

                    for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                        MedicineData medicineData = snapshot.getValue(MedicineData.class);



                    }


                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });

Upvotes: 1

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