gradle统一版本

一个项目（project）文件夹中有多个工程（module），这多个module使用的

compileSdkVersion
buildToolsVersion
minSdkVersion
targetSdkVersion
依赖库

统一管理其版本号，避免频繁修改

在module项目里的build.gradle文件中，通过下面的方式来统一版本

1.$rootProject.supportLibraryVersion
2.$rootProject.ext.junitVersion

举例

dependencies {
      compile "com.android.support:appcompat-v7:$rootProject.supportLibraryVersion"
      compile "com.android.support:cardview-v7:$rootProject.supportLibraryVersion"
      compile "com.android.support:design:$rootProject.supportLibraryVersion"
      compile "com.android.support:recyclerview-v7:$rootProject.supportLibraryVersion"
}

对比

下面是没有统一管理的依赖

dependencies {
    compile 'com.android.support:appcompat-v7:25.1.0'
    compile 'com.android.support:design:25.1.0'
    testCompile 'junit:junit:4.12'
}

当module很多的时候，如果没有统一管理，那么将可能导致很多问题：

1. A module使用24版本的v7包，B module使用25版本的v7包。当另一台电脑需要运行这些module时而不得不下载24和25两个版本的v7包，即浪费时间又浪费系统资源；
2. 而当需要更新依赖库版本时，必须一个一个module去修改，非常耗时；

废话少说，下面开始设置

代码

在project的build.gradle文件的最底部加上

ext {
    // Sdk and tools
    minSdkVersion = 15
    targetSdkVersion = 25
    compileSdkVersion = 25
    buildToolsVersion = '25.0.2'

    // App dependencies
    supportLibraryVersion = '25.1.0'
    guavaVersion = '18.0'
    junitVersion = '4.12'
    mockitoVersion = '1.10.19'
    powerMockito = '1.6.2'
    hamcrestVersion = '1.3'
    runnerVersion = '0.5'
    rulesVersion = '0.5'
    espressoVersion = '2.2.2'
}

上面的名称和版本号根据个人需要进行修改。
在module里的build.gradle里

android {
    compileSdkVersion rootProject.ext.compileSdkVersion
    buildToolsVersion rootProject.ext.buildToolsVersion

    defaultConfig {
        applicationId "你的包名"
        minSdkVersion rootProject.ext.minSdkVersion
        targetSdkVersion rootProject.ext.targetSdkVersion
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner 'android.support.test.runner.AndroidJUnitRunner'
}
dependencies {
    compile (group:'com.android.support',name:'appcompat-v7',version:"$rootProject.supportLibraryVersion")
    // App's dependencies, including test
    compile "com.android.support:appcompat-v7:$rootProject.supportLibraryVersion"
    compile "com.android.support:cardview-v7:$rootProject.supportLibraryVersion"
    compile "com.android.support:design:$rootProject.supportLibraryVersion"
    compile "com.android.support:recyclerview-v7:$rootProject.supportLibraryVersion"
    compile "com.android.support:support-v4:$rootProject.supportLibraryVersion"
    compile "com.android.support.test.espresso:espresso-idling-resource:$rootProject.espressoVersion"
    compile "com.google.guava:guava:$rootProject.guavaVersion"

    // Dependencies for local unit tests
    testCompile "junit:junit:$rootProject.ext.junitVersion"
    testCompile "org.mockito:mockito-all:$rootProject.ext.mockitoVersion"
    testCompile "org.hamcrest:hamcrest-all:$rootProject.ext.hamcrestVersion"

    // Android Testing Support Library's runner and rules
    androidTestCompile "com.android.support.test:runner:$rootProject.ext.runnerVersion"
    androidTestCompile "com.android.support.test:rules:$rootProject.ext.runnerVersion"

    // Dependencies for Android unit tests
    androidTestCompile "junit:junit:$rootProject.ext.junitVersion"
    androidTestCompile "org.mockito:mockito-core:$rootProject.ext.mockitoVersion"
    androidTestCompile 'com.google.dexmaker:dexmaker:1.2'
    androidTestCompile 'com.google.dexmaker:dexmaker-mockito:1.2'

    // Espresso UI Testing
    androidTestCompile "com.android.support.test.espresso:espresso-core:$rootProject.espressoVersion"
    androidTestCompile "com.android.support.test.espresso:espresso-contrib:$rootProject.espressoVersion"
    androidTestCompile "com.android.support.test.espresso:espresso-intents:$rootProject.espressoVersion"

    // Resolve conflicts between main and test APK:
    androidTestCompile "com.android.support:support-annotations:$rootProject.supportLibraryVersion"
    androidTestCompile "com.android.support:support-v4:$rootProject.supportLibraryVersion"
    androidTestCompile "com.android.support:recyclerview-v7:$rootProject.supportLibraryVersion"
    androidTestCompile "com.android.support:appcompat-v7:$rootProject.supportLibraryVersion"
    androidTestCompile "com.android.support:design:$rootProject.supportLibraryVersion"
}

方法二

你也可以新建一个工程级别的.gradle文件来单独装在这些版本号，但需要在module级别的build.gradle文件里添加一行代码（号表示你指定名称）。

上面删除线处更正为：“但需要在project级别”（感谢TsuiYC提醒）

apply from:"*.gradle"

在最外层（Project）工程项目build.gradle顶部添加

apply from:"version.gradle"

最终样式看图：

apply from:"version.gradle" //最外层的工程级别的build.gradle里面添加

buildscript {
    repositories {
        mavenCentral()
        google()
        jcenter()
    }

针对第二种方法，不用修改model.gradle里的任何代码

感谢

参考原作者

Android Studio中用gradle统一版本
Gradle统一依赖管理