Firebase Realtime Database接入Android应用失败求助

问题背景 #

我尝试将Firebase Realtime Database接入Android应用，操作流程如下：

• 创建空白Android项目
• 在清单文件中添加android:exported="true"（不添加会编译报错）
• 通过Android Studio的Tools菜单选择Firebase，进入Realtime Database模块，点击「get started with realtime database [KOTLIN]」
• 按照指引完成应用与Firebase的绑定，以及Realtime Database实例的创建

Firebase控制台显示应用已成功连接，且数据库已设置为测试模式安全规则。我编写了Kotlin代码，实现点击按钮时将测试数据写入数据库，并通过Toast反馈操作结果，但点击按钮后数据库无任何变化，也没有弹出任何Toast提示。

相关代码与配置 #

Activity代码 #

val testData = 110
private lateinit var database : DatabaseReference

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    val btn = findViewById<Button>(R.id.btn1)

    btn.setOnClickListener {
        database = FirebaseDatabase.getInstance().getReference("testing")

        database.setValue(testData).addOnSuccessListener {
            Toast.makeText(this,"success",Toast.LENGTH_SHORT).show()
        }.addOnFailureListener{
            Toast.makeText(this,"Fail",Toast.LENGTH_SHORT).show()
        }
    }
}

项目级build.gradle文件 #

buildscript {
    ext.kotlin_version = "1.5.31"
    repositories {
        google()
        mavenCentral()
    }
    dependencies {
        classpath "com.android.tools.build:gradle:4.2.1"
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        classpath 'com.google.gms:google-services:4.3.13'

    // NOTE: Do not place your application dependencies here; they belong
    // in the individual module build.gradle files
     }
}
allprojects {
    repositories {
        google()
        mavenCentral()
        jcenter()
    }
}
task clean(type: Delete) {
    delete rootProject.buildDir
}

应用级build.gradle文件 #

plugins {
    id 'com.android.application'
    id 'kotlin-android'
    id 'com.google.gms.google-services'
}

android {
    compileSdkVersion 31
    buildToolsVersion "30.0.3"

    defaultConfig {
        applicationId "com.lotterynumber.firebase"
        minSdkVersion 16
        targetSdkVersion 31
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
}

dependencies {

    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    implementation 'androidx.core:core-ktx:1.8.0'
    implementation 'androidx.appcompat:appcompat:1.4.0'
    implementation 'com.google.android.material:material:1.6.1'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
    implementation 'com.google.firebase:firebase-database-ktx:20.0.5'
    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
}

疑问 #

调试过程中出现以下警告：

w: Runtime JAR files in the classpath should have the same version. These files were found in the classpath:

请问这个警告是否是导致数据库写入失败、Toast不弹出的原因？该如何解决这个问题？

内容的提问来源于stack exchange，提问作者josephyumss