从 Firebase 实时数据库中检索特定数据的最快方法？

Question

I want to retrieve specific data from my database but im not sure of the quickest method to do so. This is how I have my data in the database:

I want to get the String present in the "profilePic" value for a given name ( users->Aleem->profilePic ).

This is how Im trying to get the data:

String profilePicUri="";
String searchFor="any Name";
String url = "https://as*******.firebaseio.com/users.json";

StringRequest request = new StringRequest(Request.Method.GET, url, new Response.Listener<String>(){
    @Override
    public void onResponse(String s) {
            try {
                JSONObject obj = new JSONObject(s);

                if(obj.getJSONObject(searchFor).getString("users").equals(searchFor)){
                    profilePicUri=obj.getJSONObject(searchFor).getString("profilePic");


                }

            } catch (JSONException e) {
                e.printStackTrace();
            }
        }


    }
},new Response.ErrorListener(){
    @Override
    public void onErrorResponse(VolleyError volleyError) {
        System.out.println("" + volleyError);

    }
});

RequestQueue rQueue = Volley.newRequestQueue(Login.this);
rQueue.add(request);

But the code does not work. Can someone tell me what way I should be retrieving this specific data and whats the good way to do it. Thanks a lot

Answer 1

You dont need to do a get request, firebase already offers its own api. To retrieve the data you need to do the following:

DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("users").child("Aleem");
databaseReference.addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
           String profilePic = dataSnapshot.child("profilePic").getValue(String.class);
           String password   = dataSnapshot.child("password").getValue(String.class);
    }
    @Override
    public void onCancelled(DatabaseError databaseError) {
        throw databaseError.toException();
    }
});

First add reference to the node Aleem , then attach a listener and you will be able to retrieve the data under Aleem .

Check here for more information:

https://firebase.google.com/docs/database/android/read-and-write