将androidstudio项目与Firebase集成用于google登录功能时的依赖性错误

我正在Kotlin开发一个应用程序并继续收到错误：

Failed to resolve: firebase-auth-15.0.0`

在尝试同步gradle时.我正在尝试实施谷歌登录功能.

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'com.google.gms.google-services'
android {
compileSdkVersion 28
defaultConfig {
applicationId "nus.is3261.kotlinapp"
minSdkVersion 21
targetSdkVersion 28
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.android.support.constraint:constraint-layout:1.1.3'
implementation 'com.android.support:support-v4:28.0.0'
implementation 'com.android.support:design:28.0.0'
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'
implementation 'com.google.firebase:firebase-auth:16.0.1:15.0.0'
}


我已经尝试按照堆栈溢出here的解决方案,但在同步gradle后我发出此警告警告：app gradle文件必须依赖com.google.firebase：firebase-core才能使Firebase服务按预期工作.

解决方法:

您收到以下错误：

Failed to resolve: firebase-auth-15.0.0

因为您在代码中使用了错误的依赖项.要解决此问题,请更改以下代码行：

implementation 'com.google.firebase:firebase-auth:16.0.1:15.0.0'


至

implementation 'com.google.firebase:firebase-auth:16.0.5'


因为这样的版本16.0.1：15.0.0不存在.

还请添加以下依赖项,该依赖项现在是必需的：

implementation 'com.google.firebase:firebase-core:16.0.4'


Your app gradle file now has to explicitly list com.google.firebase:firebase-core as a dependency for Firebase services to work as expected.

在您的顶级build.gradle文件中,请务必使用最新版本的Google Service插件：

classpath 'com.google.gms:google-services:4.1.0'