我的 Flutter firebase 注销与我的预订系统发生冲突

Question

我正在制作一个用于预订的应用，但我收到关于我退出的错误，这在我添加预订系统之前没有发生。

══╡ EXCEPTION CAUGHT BY PROVIDER ╞══════════════════════════════════════════════════════════════════
I/flutter ( 6595): The following assertion was thrown:
I/flutter ( 6595): An exception was throw by _MapStream<FirebaseUser, User> listened by
I/flutter ( 6595): StreamProvider<User>, but no `catchError` was provided.
I/flutter ( 6595): 
I/flutter ( 6595): Exception:
I/flutter ( 6595): NoSuchMethodError: The getter 'uid' was called on null.
I/flutter ( 6595): Receiver: null
I/flutter ( 6595): Tried calling: uid

我知道这已得到解答，但我无法使用该代码，因为我的预订页面依赖于注销不需要的一行代码。 我的预订所需的身份验证页面代码：

//create user object based on firebase user
User _userFromFirebaseUser(FirebaseUser user){

   userId(user.uid);
 //if i comment the above line out my signout works but bookings not
  return user != null ? User(uid: user.uid) : null;

}

Answer 1

您收到该错误是因为您已经退出，因此当前没有用户登录。您需要将代码更改为以下内容：

User _userFromFirebaseUser(FirebaseUser user){
    userId(user?.uid ?? "no user")
  return user != null ? User(uid: user.uid) : null;

}