Google Sign-In with LibGDX

Question

I've a problem. I'm making a game with LibGDX. Now I want to implement Google Sign-In. I searched everywhere, but can't find anything.

What I need is a Resolver to abstract code for specific platform, but I don't know how to do it. Can someone help?

EDIT

Here's the code, this is my Android Resolver:

public GoogleResolverAndroid(final Context context) {

    handler = new Handler();
    this.context = context;

    GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
            .requestEmail()
            .build();

    mGoogleApiClient = new GoogleApiClient.Builder(this.context)
            .addApi(Auth.GOOGLE_SIGN_IN_API, gso)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this)
            .build();
}
@Override
public void loginGoogle() {
    signIn();
}

@Override
public boolean getIsLoggedInGoogle() {
    return isLoggedIn;
}

public void signIn() {

    Intent signInIntent = Auth.GoogleSignInApi.getSignInIntent(mGoogleApiClient);
    ((AndroidLauncher)context).startActivityForResult(signInIntent, RC_SIGN_IN);
    mGoogleApiClient.connect();

}

private void signOut() {
    Auth.GoogleSignInApi.signOut(mGoogleApiClient).setResultCallback(
            new ResultCallback<Status>() {
                @Override
                public void onResult(Status status) {
                    isLoggedIn = false;
                }
            });
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    // Result returned from launching the Intent from GoogleSignInApi.getSignInIntent(...);
    if (requestCode == RC_SIGN_IN) {
        GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
        handleSignInResult(result);
    }

    if (requestCode == REQUEST_RESOLVE_ERROR) {
        mResolvingError = false;
        if (resultCode == RESULT_OK) {
            // Make sure the app is not already connected or attempting to connect
            if (!mGoogleApiClient.isConnecting() &&
                    !mGoogleApiClient.isConnected()) {
                mGoogleApiClient.connect();
            }
        }
    }
    } 
//some code other code
//
//
//




@Override
public void onConnected(@Nullable Bundle bundle) {

    OptionalPendingResult<GoogleSignInResult> opr = Auth.GoogleSignInApi.silentSignIn(mGoogleApiClient);
    if (opr.isDone())
    {
        Gdx.app.debug(TAG, "Loggato");
        GoogleSignInResult result = opr.get();
        handleSignInResult(result);
    } else {
        opr.setResultCallback(new ResultCallback<GoogleSignInResult>() {
            @Override
            public void onResult(GoogleSignInResult googleSignInResult) {
                handleSignInResult(googleSignInResult);
            }
        });
    }
}

@Override
public void onConnectionSuspended(int i) {
    Gdx.app.debug(TAG, "onConnectionSuspended ma non so perchè");
}

and this is my class that call the resolver method in libgdx

       // Google
    googleLoginButton = new LoginButton(tbs, stage, main);
    googleLoginButton.setPosition(stage.getViewport().getWorldWidth()/2-googleLoginButton.getWidth() - 10,
            stage.getViewport().getWorldHeight()/2-googleLoginButton.getHeight()/2 - 200);

    googleLoginButton.addListener(new ClickListener() {
        @Override
        public void clicked(InputEvent event, float x, float y) {
            main.googleResolver.loginGoogle();
            googlePrefs = main.googleResolver.getGooglePrefs();

            gLoginIn = true;

            Gdx.app.debug(TAG, googlePrefs.toString());
        }
    });

Answer 1

The way I solved this for my game was with the use of Interfacing. So you have to write Android and iOS specific code that use this interfaces from your core game.