1.Project Add Firebase
2.Create Firebase Console Auth Project
3.Read this code.. 😀
import android.widget.Toast; import com.google.android.gms.tasks.OnCompleteListener; import com.google.android.gms.tasks.Task; import com.google.firebase.auth.AuthResult; import com.google.firebase.auth.FirebaseAuth; import com.google.firebase.database.DatabaseReference; import com.google.firebase.database.FirebaseDatabase; public class MainActivity extends AppCompatActivity { private FirebaseAuth auth; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); auth = FirebaseAuth.getInstance(); firebaseLogin("username","password"); ); } public void firebaseLogin(String email, String pass){ auth.signInWithEmailAndPassword(email, password) .addOnCompleteListener(MainActivity.this, new OnCompleteListener<AuthResult>() { @Override public void onComplete(@NonNull Task<AuthResult> task) { if (task.isSuccessful()) { Toast.makeText(getApplicationContext(),"Successful",Toast.LENGTH_LONG).show(); } else { Toast.makeText(getApplicationContext(),"Login failed",Toast.LENGTH_LONG).show(); } } }); } }