Firebase, get specfic chid from parent

问题

I want to match branch value in all child of student nodes with the value I already have and if matched successfully then I want to retrieve 'Student name' value in matched child see blow image

回答1:

You're looking for a query in that case.

To match the value of branch and then print the value of studentName for all matching child nodes, you'd do:

DatabaseReference ref = FirebaseDatabase.getInstance().getReference(".../students");
Query query = ref.orderByChild("branch").equalTo("Electronics Engineering");
query.addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for (DataSnapshot studentSnapshot: dataSnapshot.getChildren()) {
            Log.d(TAG, studentSnapshot.child("studentName").getValue(String.class));
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
        throw databaseError.toException();
    }
}

来源：https://stackoverflow.com/questions/60405198/firebase-get-specfic-chid-from-parent