如何从 Flutter 注销 Google Auth？

Question

我能够成功 - 使用 Google 和 Facebook 使用 firebase 登录用户：

firebase_auth.dart、flutter_facebook_login.dart、google_sign_in.dart

我可以从不同的小部件使用此功能注销 firebase 用户：

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

现在这是 Google 和 Facebook 两种登录类型的统称，我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，如果我的注销功能在不同的小部件和文件中，我如何传递要引用的 GoogleSignIn 对象以注销？

Answer 1

GoogleSignIn 和 FacebookSignIn 有 bool Future 类型的方法。

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

你会得到真或假使用这个你可以使用退出方法。解决方案的第二个问题是为 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();
}