使用Gradle Wrapper构建项目时找不到com.android.tools.build:gradle:3.0.1

我最近碰到了个特别头疼的问题：用Gradle Wrapper执行./gradlew命令构建Android项目时直接失败，报错找不到com.android.tools.build:gradle:3.0.1依赖，但在Android Studio里点击构建却完全正常。试了好几种办法都没解决，最后终于找到原因了，分享给同样踩坑的朋友。

报错信息 #

FAILURE: Build failed with an exception.
* What went wrong:
A problem occurred configuring project ':app'.
> Could not resolve all files for configuration ':app:classpath'.
> Could not find com.android.tools.build:gradle:3.0.1.
Searched in the following locations:
https://maven.fabric.io/public/com/android/tools/build/gradle/3.0.1/gradle-3.0.1.pom
https://maven.fabric.io/public/com/android/tools/build/gradle/3.0.1/gradle-3.0.1.jar
https://jcenter.bintray.com/com/android/tools/build/gradle/3.0.1/gradle-3.0.1.pom
https://jcenter.bintray.com/com/android/tools/build/gradle/3.0.1/gradle-3.0.1.jar
Required by: project :app
* Try:
Run with --stacktrace option to get the stack trace.
Run with --info or --debug option to get more log output.
* Get more help at https://help.gradle.org

我试过的无效方法 #

• 确认Gradle Wrapper版本是4.1（和Android Studio里使用的版本一致）
• 在根目录build.gradle中添加了google()仓库
• 尝试设置android.enableAapt2=false

我的初始配置文件 #

根目录build.gradle #

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.1'
        // 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
}

gradle-wrapper.properties #

distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-all.zip

最终解决方法 #

原来我被官方文档的描述误导了！文档说“要将此类库添加到构建中，请在顶层build.gradle文件中包含Google的Maven仓库”，但实际上还需要在app模块的build.gradle文件中也添加buildscript的仓库配置：

修改app/build.gradle，添加以下内容：

...
buildscript {
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.1'
    }
}
...

添加之后再执行./gradlew，构建就正常通过了！

内容的提问来源于stack exchange，提问作者FGarcia