ANDROID STUDIO中统一管理版本号引用配置

为了提高项目开发效率，在实际项目开发过程中往往会引入一些开源框架，还有项目中使用的各种Module，当引入Module过多时最好提供一种统一的方式去管理版本号，如：compileSdkVersion、buildToolsVersion、androidTestCompile 等，便于日后对版本号进行维护，此处记录第2种方式处理上述问题
1.在工程根目录下的build.gradle文件下添加 ext{ .... } 中的内容

// Top-level build file where you can add configuration options common to all sub-projects/modules.
//apply from:"config.gradle"/*引入配置文件:config.gradle*/
buildscript {
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.0'
        // 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
}
ext {
    minSdkVersion = 15
    targetSdkVersion = 27
    compileSdkVersion = 27
    supportLibraryVersion = '27.+'
}
//或者使用下面的写法也是可以的
/*project.ext {
    minSdkVersion = 15
    targetSdkVersion = 27
    compileSdkVersion = 27
    supportLibraryVersion = '27.+'
}*/

2.在app目录下或者依赖的model目录下的build.gradle中使用 $rootProject.supportLibraryVersion

apply plugin: 'com.android.application'

android {

    compileSdkVersion rootProject.ext.compileSdkVersion

    defaultConfig {
        applicationId "com.example.think"
        minSdkVersion rootProject.ext.minSdkVersion
        targetSdkVersion rootProject.ext.targetSdkVersion
        versionCode rootProject.ext.versionCode
        versionName rootProject.ext.versionName
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    implementation "com.android.support:appcompat-v7:$rootProject.supportLibraryVersion"
    implementation "com.android.support:cardview-v7:$rootProject.supportLibraryVersion"
    implementation "com.android.support:design:$rootProject.supportLibraryVersion"
}

3,进行同步的操作,即可引用成功,如果需要配置版本,我们只需在工程的根目录下的ext {}中进行响应的配置更改即可,这样整个工程中的所有model都会使用相同的版本.