我的应用程序没有再次构建，不知道我做错了什么。下面列出了错误消息

C:\flutter\flutter\.pub-cache\hosted\pub.dartlang.org\firebase_auth-0.8.0+1\android\src\main\java\io\flutter\plugins\firebaseauth\FirebaseAuthPlugin.java:9: error: package androidx.annotation does not exist
import androidx.annotation.NonNull;
                          ^
C:\flutter\flutter\.pub-cache\hosted\pub.dartlang.org\firebase_auth-0.8.0+1\android\src\main\java\io\flutter\plugins\firebaseauth\FirebaseAuthPlugin.java:10: error: package androidx.annotation does not exist
import androidx.annotation.Nullable;
                          ^
C:\flutter\flutter\.pub-cache\hosted\pub.dartlang.org\firebase_auth-0.8.0+1\android\src\main\java\io\flutter\plugins\firebaseauth\FirebaseAuthPlugin.java:638: error: cannot find symbol

最佳答案

解决方案

在 firebase_auth 库的 build.gradle 中添加:implementation 'androidx.annotation:annotation:1.0.1'。我使用 Android Studio 来查看 Flutter 的 android 应用结构。

来自 Android Studio

示例代码:

android {
    compileSdkVersion 28

    defaultConfig {
        minSdkVersion 16
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    lintOptions {
        disable 'InvalidPackage'
    }
    dependencies {
        api 'com.google.firebase:firebase-auth:16.0.1'
        implementation 'androidx.annotation:annotation:1.0.1'
    }
}

  flutter:
    sdk: flutter
  rxdart: ^0.20.0
  firebase_core: ^0.3.0
  firebase_analytics: ^2.0.0
  firebase_auth: ^0.8.0+1
  google_sign_in: ^4.0.0

https://stackoverflow.com/questions/54375396/