flutterfirebasegoogleauthlogin遲到的錯誤

https://dev.to/movingmelody/flutter-firebase-google-sign-in-auth-with-splashscreen-using-updated-api-23ad

我嘗試在此站點的初始螢屏期間使用 google auth 登錄代碼，但我仍然收到遲到的錯誤

class SplashScreen extends StatefulWidget {
  @override
  _SplashScreenState createState() => _SplashScreenState();
}

class _SplashScreenState extends State<SplashScreen> {
  final FirebaseAuth _auth = FirebaseAuth.instance;
  late User _user;

  @override
  void initState() {
    super.initState();
    initializeUser();
    _initUser();
  }
  Future initializeUser() async {
    await Firebase.initializeApp();
    final User? firebaseUser = await FirebaseAuth.instance.currentUser;
    await firebaseUser!.reload();
    _user = (await _auth.currentUser)!;
    // get User authentication status here
  }
  _initUser() async {
    if (_auth.currentUser != null) {
      Timer(
        Duration(seconds: 2),
            () => Navigator.of(context).pushAndRemoveUntil(
                MaterialPageRoute(
                    builder: (context) =>
                        MainScreen(_user)),
                    (Route<dynamic> route) => false),
      );
    } else {
      Timer(Duration(seconds: 1),
              () => Navigator.of(context).pushAndRemoveUntil(
                  MaterialPageRoute(
                      builder: (context) =>
                          MyHomePage()),
                      (Route<dynamic> route) => false),
      );
    }
  }

  @override
  Widget build(BuildContext context) {

    return Scaffold(
        body: Center(
          child: Text("Splash Screen"),
        ),

    );
  }
}

MyHomePage() 或 MainScreen(_user) 的內容也按原樣鍵入了站點代碼，但錯誤仍然存??在。在gradle升級之前，這段代碼運行正常，但是在jdk版本up和gradle升級之后，該死的遲到的錯誤并沒有停止。

這是錯誤

Performing hot restart...
Syncing files to device sdk gphone x86...
Restarted application in 1,320ms.
W/DynamiteModule( 6646): Local module descriptor class for com.google.android.gms.providerinstaller.dynamite not found.
I/DynamiteModule( 6646): Considering local module com.google.android.gms.providerinstaller.dynamite:0 and remote module com.google.android.gms.providerinstaller.dynamite:0
W/ProviderInstaller( 6646): Failed to load providerinstaller module: No acceptable module com.google.android.gms.providerinstaller.dynamite found. Local version is 0 and remote version is 0.
I/om.gwon.goodma( 6646): The ClassLoaderContext is a special shared library.
I/om.gwon.goodma( 6646): The ClassLoaderContext is a special shared library.
I/TetheringManager( 6646): registerTetheringEventCallback:com.gwon.goodman
V/NativeCrypto( 6646): Registering com/google/android/gms/org/conscrypt/NativeCrypto's 294 native methods...
W/om.gwon.goodma( 6646): Accessing hidden method Ljava/security/spec/ECParameterSpec;->getCurveName()Ljava/lang/String; (greylist, reflection, allowed)
I/ProviderInstaller( 6646): Installed default security provider GmsCore_OpenSSL
I/FirebaseAuth( 6646): [FirebaseAuth:] Preparing to create service connection to fallback implementation
W/System  ( 6646): Ignoring header X-Firebase-Locale because its value was null.
W/om.gwon.goodma( 6646): Accessing hidden field Ljava/net/Socket;->impl:Ljava/net/SocketImpl; (greylist, reflection, allowed)
W/om.gwon.goodma( 6646): Accessing hidden method Ldalvik/system/CloseGuard;->get()Ldalvik/system/CloseGuard; (greylist,core-platform-api, linking, allowed)
W/om.gwon.goodma( 6646): Accessing hidden method Ldalvik/system/CloseGuard;->open(Ljava/lang/String;)V (greylist,core-platform-api, linking, allowed)
W/om.gwon.goodma( 6646): Accessing hidden method Ljava/security/spec/ECParameterSpec;->setCurveName(Ljava/lang/String;)V (greylist, reflection, allowed)
W/om.gwon.goodma( 6646): Accessing hidden method Ldalvik/system/BlockGuard;->getThreadPolicy()Ldalvik/system/BlockGuard$Policy; (greylist,core-platform-api, linking, allowed)
W/om.gwon.goodma( 6646): Accessing hidden method Ldalvik/system/BlockGuard$Policy;->onNetwork()V (greylist, linking, allowed)

======== Exception caught by widgets library =======================================================
The following LateError was thrown building MainScreen(dirty, dependencies: [_InheritedProviderScope<Pro?>], state: _MainScreenState#c8d34):
LateInitializationError: Field '_instance@21075166' has not been initialized.

The relevant error-causing widget was: 
  MainScreen MainScreen:file:///F:/flutter project/good_man/lib/main.dart:81:25

該站點上的代碼是 2020 年 11 月的代碼，但與此同時，Timer 和 google auth 的規則發生了變化......即使您撰寫使用 Future 并檢查 null 的相同代碼，該錯誤仍然存??在使用 ![在此處輸入影像描述][1]

這不是最后一個遲到的問題帖子的副本。在看到那篇文章的建議后，我寫下了我第一次寫這段代碼的博客的相同代碼，但我仍然為保持Late錯誤而感到尷尬。

uj5u.com熱心網友回復：

即使您在 initUser() 中初始化這些變數，但如果您在 build() 方法中使用變數，您將收到此錯誤，因為 initUser() 是異步的，這意味著從集合中獲取資料需要時間。要解決此問題，您可以執行以下操作：

@override
  void initState() {  
    super.initState();
    _initUser().whenComplete((){
      setState(() {});
   });
  }

這將使用新值重建小部件樹。

uj5u.com熱心網友回復：

您不需要使用Late，您應該使用空檢查運算子'?'

只需更換

Late User _user

和

User? _user

標籤：

上一篇：請在此處解釋dart中Futures的行為

下一篇：僅在顫動中淡入影片