Use AWS SDK
For advanced use cases where Amplify does not provide the functionality you're looking for, you can retrieve the escape hatch to access the underlying SDK.
The escape hatch provides access to the underlying AWSMobileClient instance.
AWSMobileClient mobileClient = (AWSMobileClient) Amplify.Auth.getPlugin("awsCognitoAuthPlugin").getEscapeHatch();val cognitoAuthPlugin = Amplify.Auth.getPlugin("awsCognitoAuthPlugin")val mobileClient = cognitoAuthPlugin.escapeHatch as AWSMobileClientval cognitoAuthPlugin = Amplify.Auth.getPlugin("awsCognitoAuthPlugin")val mobileClient = cognitoAuthPlugin.escapeHatch as AWSMobileClientAWSMobileClient mobileClient =    (AWSMobileClient) RxAmplify.Auth.getPlugin("awsCognitoAuthPlugin").getEscapeHatch();You can use the escape hatch to federatedSignIn with a valid token from other social providers. Find more details here
mobileClient.federatedSignIn(IdentityProvider.FACEBOOK.toString(), "<FACEBOOK_TOKEN_HERE>", new Callback<UserStateDetails>() {    @Override    public void onResult(final UserStateDetails userStateDetails) {        //Handle the result    }
    @Override    public void onError(Exception e) {        Log.e(TAG, "sign-in error", e);    }});