如何从Flutter退出Google Auth？

Question

我能够使用Google和Facebook成功登录firebase用户：

firebase_auth。飞镖，扑翼_facebook_登录。dart，google_sign_in.dart

我可以使用此功能从不同的小部件注销Firebase用户：

  Future<void>_signOut() async {
    final FirebaseAuth _firebaseAuth = FirebaseAuth.instance;
    return _firebaseAuth.signOut();
  }

现在，这是两种登录方式（Google和Facebook）的全部功能，如何确定用户是否是Google auth用户，在这种情况下，我可以执行

    final GoogleSignIn _googleSignIn = new GoogleSignIn();
...
    _googleSignIn.signOut();

此外，如果我的签出函数在不同的小部件和文件中，我如何传递要引用的GoogleSignIn对象以签出？

Answer 1

GoogleSignIn和FacebookSignIn有一个bool Future类型的方法。

final facebookLogin = FacebookLogin();
final GoogleSignIn googleSignIn = new GoogleSignIn();
     googleSignIn.isSignedIn().then((s) {});
      facebookLogin.isLoggedIn.then((b) {});

使用此方法，您将得到正确或错误。您可以使用注销方法。对于第二个问题，解决方案是为GoogleSignIn和facebook创建一个全局对象。

import 'dart:async';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:google_sign_in/google_sign_in.dart';
import 'package:flutter_facebook_login/flutter_facebook_login.dart';

final facebookLogin = FacebookLogin();
final FirebaseAuth firebaseAuth = FirebaseAuth.instance;
final GoogleSignIn googleSignIn = new GoogleSignIn();

Future<FirebaseUser> signInWithGoogle() async {
  // Attempt to get the currently authenticated user
  GoogleSignInAccount currentUser = _googleSignIn.currentUser;
  if (currentUser == null) {
    // Attempt to sign in without user interaction
    currentUser = await _googleSignIn.signInSilently();
  }
  if (currentUser == null) {
    // Force the user to interactively sign in
    currentUser = await _googleSignIn.signIn();
  }

  final GoogleSignInAuthentication googleAuth =
      await currentUser.authentication;

  // Authenticate with firebase
  final FirebaseUser user = await firebaseAuth.signInWithGoogle(
    idToken: googleAuth.idToken,
    accessToken: googleAuth.accessToken,
  );

  assert(user != null);
  assert(!user.isAnonymous);

  return user;
}

Future<Null> signOutWithGoogle() async {
  // Sign out with firebase
  await firebaseAuth.signOut();
  // Sign out with google
  await googleSignIn.signOut();
}