如何解决异常错误：名为[DEFAULT]的FirebaseApp不'；不存在？

以下是发生异常的地方：

 @override
  Future<FirebaseUser> getCurrentUser() async {
    FirebaseUser user = await _firebaseAuth.currentUser();
    return user;
  }

我的颤振医生输出：

[flutter] flutter doctor -v
[√] Flutter (Channel stable, v1.12.13+hotfix.5, on Microsoft Windows [Version 10.0.17763.914], locale en-US)
    • Flutter version 1.12.13+hotfix.5 at D:\src\flutter
    • Framework revision 27321ebbad (7 days ago), 2019-12-10 18:15:01 -0800
    • Engine revision 2994f7e1e6
    • Dart version 2.7.0

[!] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
    • Android SDK at C:\Users\jcdos\AppData\Local\Android\sdk
    • Android NDK location not configured (optional; useful for native profiling support)
    • Platform android-29, build-tools 29.0.2
    • Java binary at: D:\Android Studio\jre\bin\java
    • Java version OpenJDK Runtime Environment (build 1.8.0_202-release-1483-b03)
    ! Some Android licenses not accepted.  To resolve this, run: flutter doctor --android-licenses

[!] Android Studio (version 3.5)
    • Android Studio at D:\Android Studio
    X Flutter plugin not installed; this adds Flutter specific functionality.
    X Dart plugin not installed; this adds Dart specific functionality.
    • Java version OpenJDK Runtime Environment (build 1.8.0_202-release-1483-b03)

[!] Connected device
    ! No devices available

! Doctor found issues in 3 categories.
exit code 0

这是我的调试控制台：

E/flutter ( 6562): #40     SingleChildRenderObjectElement.mount 
package:flutter/…/widgets/framework.dart:5445
E/flutter ( 6562): #41     Element.inflateWidget 
package:flutter/…/widgets/framework.dart:3194
E/flutter ( 6562): #42     Element.updateChild 
package:flutter/…/widgets/framework.dart:2988
E/flutter ( 6562): #43     ComponentElement.performRebuild 
package:flutter/…/widgets/framework.dart:4243
E/flutter ( 6562): #44     Element.rebuild 
package:flutter/…/widgets/framework.dart:3947
E/flutter ( 6562): #
√ Built build\app\outputs\apk\debug\app-debug.apk.

我试图找到其他来源来修复错误，但没有任何效果。我从应用程序gradle中删除了apply插件：“com.google.gms.googleservices”，因为这会给我带来其他问题。去掉这个，我就修复了它，因为我找到的消息来源说它已经在别的地方被调用了

如果我保留com.google.gms.google-services，则会出现以下错误，从而阻止应用程序在模拟器中运行：

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:processDebugGoogleServices'.
> No matching client found for package name 'com.example.testapp

---

在Android studio中运行应用程序，它应该显示一些需要更新的错误或文件，如build.gradle文件。此外，您还需要firebase的com.google.gms.google-services。

将以下行添加到您的android/app/build.gradle文件中：

apply plugin: 'com.google.gms.google-services'

---

您不应该删除谷歌服务插件。这就是在应用程序启动时安排初始化Firebase的原因，也是导致您现在看到的错误的原因。如果你认为这会导致其他问题，你应该解决这些问题。@DougStevenson我更新了底部的问题，如果我使用google服务插件，就会出现错误

apply plugin: 'com.google.gms.google-services'