Android Studio中的modules classes.jar错误（尝试连接到Firebase时）中发现的重复类是什么？如何解决？

我试图在Android应用程序中使用Firebase数据库，但我遇到了一些错误： 我首先得到了这个错误：

Manifest merger failed : Attribute application@appComponentFactory value=(android.support.v4.app.CoreComponentFactory) from [com.android.support:support-compat:28.0.0] AndroidManifest.xml:22:18-91
    is also present at [androidx.core:core:1.0.0] AndroidManifest.xml:22:18-86 value=(androidx.core.app.CoreComponentFactory).
    Suggestion: add 'tools:replace="android:appComponentFactory"' to <application> element at AndroidManifest.xml:6:5-24:19 to override.

Android Manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"

    package="com.example.appv1">

    <application
        tools:node="replace"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

build.gradle（模块：应用程序）：

apply插件：“com.android.application”
安卓{
编译DK28版
默认配置{
applicationId“com.example.appv1”
明斯克版本16
targetSdkVersion 28
版本代码1
版本名称“1.0”
TestInstrumentRunner“android.support.test.runner.AndroidJUnitRunner”
}
建筑类型{
释放{
minifyEnabled false
proguard文件GetDefaultProGuard文件（'proguard-android-optimize.txt'），'proguard rules.pro'
}
}
}
依赖关系{
实现文件树（目录：“libs”，包括：['*.jar']）
实现'com.android.support:appcompat-v7:28.0.0'
实现'com.android.support:design:28.0.0'
实现'com.android.support.constraint:constraint布局：1.1.3'
测试实现'junit:junit:4.12'
androidTestImplementation'com.android.support.test:runner:1.0.2'
androidTestImplementation'com.android.support.test.espresso:espresso核心：3.0.2'
//显示图像
实现'com.github.bumptech.glide:glide:3.6.1'
//火基
实现'com.google.firebase:firebase数据库：9.6.0'
//添加要在应用程序中使用的任何其他Firebase产品的SDK
//例如，使用Firebase身份验证和云Firestore
实现'com.google.firebase:firebase auth:19.1.0'
实现'com.google.firebase:firebase-firestore:21.2.1'
实现'com.firebaseui:firebaseui auth:4.3.1'
}
存储库{
jcenter（）
maven{//您正在使用需要androidx库的firebase版本。是的，谢谢@Gabriele Mariotti！我已通过将库更改为androidx所需的库来解决此错误！
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"

    package="com.example.appv1">

    <application
        tools:node="replace"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

 apply plugin: 'com.android.application'

    android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.example.appv1"
        minSdkVersion 16
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    }



dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support:design:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    // Displaying images
    implementation 'com.github.bumptech.glide:glide:3.6.1'
    // Firebase
    implementation 'com.google.firebase:firebase-database:9.6.0'
    // Add the SDKs for any other Firebase products you want to use in your app
    // For example, to use Firebase Authentication and Cloud Firestore
    implementation 'com.google.firebase:firebase-auth:19.1.0'
    implementation 'com.google.firebase:firebase-firestore:21.2.1'
    implementation 'com.firebaseui:firebase-ui-auth:4.3.1'
    }
    repositories {
        jcenter()
        maven {                                  // <-- Add this
            url 'https://maven.google.com/'
        }
    }
    apply plugin: 'com.google.gms.google-services'

build.gradle (Project:Appv1)

    buildscript {
        repositories {
            google()
            jcenter()

        }
        dependencies {
            classpath 'com.android.tools.build:gradle:3.4.1'
            classpath 'com.google.gms:google-services:3.0.0'

            // NOTE: Do not place your application dependencies here; they belong
            // in the individual module build.gradle files
        }
    }

    allprojects {
        repositories {
            google()
            jcenter()

        }
    }

    task clean(type: Delete) {
        delete rootProject.buildDir
    }