How to redirect multiple types of users to their respective Activities?

Question

I am creating a voting app on Firebase. I have 3 types of users. So far i can successfully redirect 2 kinds of users (STUDENTS, TEACHERS) to their respective activities afte

Answer 1

Using onlye if (dataSnapshot.exists()) will not solve your 3 types of user problem. Assuming that the type of the third user is 3, a change in your database structure is needed. So your new database schema should look like this:

Firebase-root
    |
    --- users
          |
          --- uidOne
          |     |
          |     --- name: "Ed"
          |     |
          |     --- type: 1
          |
          --- uidTwo
          |     |
          |     --- name: "Tyff"
          |     |
          |     --- type: 2
          |
          --- uidOne
                |
                --- name: "Admin"
                |
                --- type: 3

Now you shoud add a listener on the uid node and check the type of the user like this:

String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference uidRef = rootRef.child("users").child(uid);
ValueEventListener valueEventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        if(dataSnapshot.child("Type").getValue(Long.class) == 1) {
            startActivity(new Intent(MainActivity.this, student.class));
        } else if (dataSnapshot.child("TYPE").getValue(Long.class) == 2) {
            startActivity(new Intent(MainActivity.this, teacher.class));
        } else if (dataSnapshot.child("TYPE").getValue(Long.class) == 3) {
            startActivity(new Intent(MainActivity.this, admin.class));
        }
    }

    @Override
    public void onCancelled(@NonNull DatabaseError databaseError) {
        Log.d(TAG, databaseError.getMessage());
    }
};
uidRef.addListenerForSingleValueEvent(valueEventListener);

Answer 2

you need another data-structure, with users and roles/admin, roles/teacher, roles/student and then check which node has the key (also compatible with security rules).

as you have it, you could simply remove the else branch and query all three nodes.