title: Android app Facebook Sign-In remembers user, but Google Sign In doesn't
body: <p>So I've implemented Facebook sign-in, now I've implemented Google. It signs in successfully, but when I restart the app, the user has to log in again. If I log in with FB however, it does as it should.
  Here's my <code>AuthListener</code>:</p>
  
  <pre><code>mAuthListener = new FirebaseAuth.AuthStateListener() {
          @Override
          public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
              FirebaseUser user = firebaseAuth.getCurrentUser();
              if (user != null) {
                  Log.d("AD", "User is logged in.");
                  SignUp.this.startActivity(startMainActivity);
              } else {
                  Log.d("AD", "User is not logged in.");
              }
          }
      };
  </code></pre>
  
  <p>And everything else to do with Google Sign In:</p>
  
  <pre><code>mGoogleApiClient = new GoogleApiClient.Builder(this)
              .enableAutoManage(this /* FragmentActivity */, new GoogleApiClient.OnConnectionFailedListener() {
                  @Override
                  public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
                      Toast.makeText(SignUp.this, "There has been an error connecting to Google: " + connectionResult.getErrorMessage(), Toast.LENGTH_LONG).show();
                  }
              } /* OnConnectionFailedListener */)
              .addApi(Auth.GOOGLE_SIGN_IN_API, gso)
              .build();
      SignInButton signInButton = (SignInButton) findViewById(R.id.sign_in_button);
      signInButton.setOnClickListener(this);
  </code></pre>
  
  <hr>
  
  <pre><code>private void signIn() {
              Intent signInIntent = Auth.GoogleSignInApi.getSignInIntent(mGoogleApiClient);
              startActivityForResult(signInIntent, RC_SIGN_IN);
          }
  </code></pre>
  
  <hr>
  
  <pre><code>@Override
  protected void onActivityResult(int requestCode, int resultCode, Intent data) {
      super.onActivityResult(requestCode, resultCode, data);
      mCallbackManager.onActivityResult(requestCode, resultCode, data);
      if (requestCode == RC_SIGN_IN) {
          GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
          handleSignInResult(result);
      }
  </code></pre>
  
  <hr>
  
  <pre><code>private void handleSignInResult(GoogleSignInResult result) {
      Log.d("AD", "Signed in via google successfully:" + result.isSuccess());
      if (result.isSuccess()) {
          // Signed in successfully, show authenticated UI.
          this.startActivity(startMainActivity);
      } else {
          // Signed out, show unauthenticated UI.
          Toast.makeText(this, "An error has occurred", Toast.LENGTH_SHORT).show();
      }
  }
  </code></pre>
  
  <p>It's weird; I always have trouble with Google and nothing else :{</p>