android - 未能获取 FirebaseDatabase 实例。在 FirebaseApp 中指定 DatabaseURL

Question

FirebaseApp 调用时抛出异常 FirebaseDatabase.getInstance() .
错误信息

Failed to get FirebaseDatabase instance: Specify DatabaseURL withinFirebaseApp or from your getInstance() call.

Firebase项目配置正确。 Authentication正常工作，但无法连接到 firebase .
这是我的应用级 gradle.build 文件
build.gradle

dependencies {
    .....

    //Firebase database
    implementation 'com.google.firebase:firebase-database:11.6.2'
    // Firebase Invitation
    implementation 'com.google.firebase:firebase-invites:11.6.2'
    // Firebase Authentication
    implementation 'com.google.firebase:firebase-auth:11.6.2'
    // Google Sign In SDK (only required for Google Sign In)
    implementation 'com.google.android.gms:play-services-auth:11.6.2'

    // people api request libraries
    implementation 'com.google.api-client:google-api-client:1.22.0'
    implementation 'com.google.api-client:google-api-client-android:1.22.0'
    implementation 'com.google.apis:google-api-services-people:v1-rev4-1.22.0'
    compile project(':customsupport')
}

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

和项目级 build.gradle 文件

buildscript {
    repositories {
        jcenter()
        maven { url 'https://maven.fabric.io/public' }
    }

    dependencies {
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
        classpath 'com.android.tools.build:gradle:3.0.1'
        classpath 'com.google.gms:google-services:3.1.2'

        // We recommend changing it to the latest version from our changelog:
        // https://docs.fabric.io/android/changelog.html#fabric-gradle-plugin
        classpath 'io.fabric.tools:gradle:1.24.4'
    }
}

一个 数据库异常 将发生在 FirebaseDatabase.class

public static synchronized FirebaseDatabase getInstance(FirebaseApp var0, String var1) {
        if(TextUtils.isEmpty(var1)) {
            throw new DatabaseException("Failed to get FirebaseDatabase instance: Specify DatabaseURL within FirebaseApp or from your getInstance() call.");
        } else {
...
}

Answer 1

如果有人在 2021 年遇到这个问题，那么只需按照以下步骤操作:-
在 build.gradle/app 中添加这些依赖项

  implementation platform('com.google.firebase:firebase-bom:26.3.0')
implementation 'com.google.firebase:firebase-database-ktx'

然后使用 databasereference 对象

databaseReference=Firebase.database.getReference("Users")

仍然感到困惑，然后在此处阅读此文档 1