How can I get child value with if & else condition (Firebase,SDK) - firebase

Question

I am having trouble with my codes. What I want to do in my Login page is log as admin using email/password and when "role" is equal to admin (the other role is Guest). The admin page is MainActivity.class and the Guest page is Home.class. Can someone help me :)
And here is my code:
private void onAuthSuccess(FirebaseUser user) {
DatabaseReference ref =
FirebaseDatabase.getInstance().getReference().child("users");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String role = ds.getKey();
DatabaseReference userKeyDatabase = FirebaseDatabase.getInstance().getReference().child("users");
ValueEventListener eventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot == null) {
Toast.makeText(getApplicationContext(), "****NULLL****", Toast.LENGTH_LONG).show();
} else if(dataSnapshot.child("role").getValue().equals("Admin")) {
startActivity(new Intent(SignInActivity.this, MainActivity.class));
finish();
}else{
startActivity(new Intent(SignInActivity.this, Home.class));
finish();
}
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
userKeyDatabase.addListenerForSingleValueEvent(eventListener);
}}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
ref.addListenerForSingleValueEvent(valueEventListener);
}
I am not sure about my code as well :(

Answer 1

To check role of users login you can do something like this
FirebaseDatabase firebaseDatabase=FirebaseDatabase.getInstance();
DatabaseReference db=firebaseDatabase.getReference().child("users");
db.orderByChild("email").equalTo(email).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot)
if(dataSnapshot.exists()){
Log.d("user exits","usere hai");
String value =dataSnapshot.child("role").getValue().toString();
if(value.equals("Admin") && value != null){
startActivity(new Intent(SignInActivity.this, MainActivity.class));
finish();
}else{
startActivity(new Intent(SignInActivity.this, Home.class));
finish();
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) { }
});