CODEWITHSUNDEEP
androidfirebasefirebase-realtime-database
rajat singh
rajat singh

Reputation: 195

How to retrieve data and specific user data from the Firebase

I am having problem in retrieving data from firebase. I have one root user's node and then inside that root I have one userID child node. Inside that child node I am storing user information according to its blood group.

Now, what I want is to fetch the name and email according to blood group, say fetch all user data whose blood group is B+.

Also, please tell me on how to fetch all entries in the firebase and show on textView.

    //show data on text view
    datashow.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Log.i("inside click", "onClick: ");
            FirebaseDatabase database = FirebaseDatabase.getInstance();
            DatabaseReference db = database.getReference();
            db.child("users").addValueEventListener(new ValueEventListener() {
                @Override
                public void onDataChange(DataSnapshot dataSnapshot) {
                    User user = dataSnapshot.getValue(User.class);
                    if (user == null) {
                        Log.e(TAG, "User data is null!");
                        return;
                    }
                    Iterable<DataSnapshot > children = dataSnapshot.getChildren();
                    Log.i("children", "onDataChange: " + children);
                    for(DataSnapshot child : children)
                    {
                        Map<String , String> map = (Map)child.getValue();
                        Log.i("inside", "onDataChange: " + map);
                        name  = map.get("name");
                        email = map.get("email");
                        dateof = map.get("userDob");
                        showData(name , email  , dateof );
                        Log.i("datasnap", "onDataChange: data snapshot " + name + email + dateof);
                    }
                }

                @Override
                public void onCancelled(DatabaseError databaseError) {

                }
            });
        }
    });

this is my snapshot for Firebase database

enter image description here

Upvotes: 3

Views: 6301

Answers (2)

Rihab
Rihab

Reputation: 67

    db.child("users").orderByChild("userBloodGroup").equalTo("B+").addValueEventListener(new ValueEventListener() {
                @Override
                public void onDataChange(DataSnapshot snapshot) {
             List<User> data = new ArrayList<>();
                    if (dataSnapshot.exists()) {
                for (DataSnapshot snapshot :
                        dataSnapshot.getChildren()) {
                   User element = snapshot.getValue(User.class);
                    element.setKey(snapshot.getKey());
                    data.add(element);

                }
           for (User user: data){
Log.i(TAG,"user name: " +user.getName());
    Log.i(TAG,"user email: " +user.getEmail());
  Log.i(TAG,"user dob: " +user.getUserDob());
 }
                }
        @Override
        public void onCancelled(DatabaseError databaseError) {
            Log.i(TAG, "loadPost:onCancelled", databaseError.toException());
        }

    });

Upvotes: 1

Kurt Acosta
Kurt Acosta

Reputation: 2537

To query for all users with the bloodGroup B+, use a Firebase Query:

firebaseReference("users").orderByChild("userBloodGroup").equalTo("B+")

To get all the data of the users, you could use a Listener to get all of them and put them in whatever TextView you need. You could check the documentation on Firebase on how they read data. https://firebase.google.com/docs/database/android/read-and-write

Upvotes: 0

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