打开构建。Gradle文件位于这里:

这是编写依赖库的旧方法(对于gradle版本2及以下):

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile files('libs/volley.jar')
    compile 'com.android.support:support-v4:21.+'
}

这是导入gradle版本3依赖项的新方法(正确的):

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    testImplementation 'junit:junit:4.12'
    implementation files('libs/volley.jar')
    implementation 'com.android.support:support-v4:21.+'
}

我已经尝试在Android Studio 3.0.1中将谷歌gms服务更改为最新的com.google.gms:google-services:3.2.1，但警告仍然存在。

根据编译器的建议，我将所有编译依赖项更改为实现，并将testCompile更改为testimplemimplementation，如下所示。

dependencies {
implementation fileTree(include: ['*.jar'], dir: 'libs')
implementation 'com.android.support:appcompat-v7:27.1.1'
implementation 'com.android.support:mediarouter-v7:27.1.1'
implementation 'com.android.support:design:27.1.1'
implementation 'com.google.firebase:firebase-ads:12.0.1'
implementation 'com.google.firebase:firebase-crash:12.0.1'
implementation 'com.google.firebase:firebase-core:12.0.1'
implementation 'com.google.firebase:firebase-messaging:12.0.1'
implementation 'com.google.firebase:firebase-perf:12.0.1'
implementation 'com.google.firebase:firebase-appindexing:12.0.1'
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
testImplementation 'junit:junit:4.12'
implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
}

最后，警告被删除!

回到你的位置。在项目级别的Gradle文件中，您会发现以下行突出显示

dependencies {
    classpath 'com.android.tools.build:gradle:3.1.4'  //place your cursor over here 
    //and hit alt+enter and it will show you the appropriate version to select


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

    classpath 'com.google.gms:google-services:4.0.2' //the same as previously
}

当前版本为4.2.0:

构建脚本 {

repositories {
    google()
    jcenter()
}
dependencies {
    classpath 'com.android.tools.build:gradle:3.4.0'

    // NOTE: Do not place your application dependencies here; they belong
    // in the individual module build.gradle files
    classpath 'com.google.gms:google-services:4.2.0'
}

}

在我的情况下，这是由Realm库引起的，在我将它更新到Realm的最新版本(目前为止为5.1.0)后，问题解决了!

下面是gradle的工作脚本:

buildscript {
repositories {
    jcenter()
    google()
}

dependencies {
    classpath 'com.android.tools.build:gradle:3.1.2'
    classpath "io.realm:realm-gradle-plugin:5.1.0"
    // NOTE: Do not place your application dependencies here; they belong
    // in the individual module build.gradle files
    classpath 'com.google.gms:google-services:3.2.1'
  }
}

回复谷歌:https://issuetracker.google.com/issues/74048134

会有一些依赖仍然使用编译，仔细检查你的应用程序依赖和传递依赖。