Gradle应用例子（二）（待更）

例子5 编写一个通用的利于管理依赖库版本的脚本文件

参考项目

googlesamples的BasicSample

再应用Android插件时，我们通常会配置很多版本号，例如

...
buildscript {
    
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.2'
    }
}
...

其中的com.android.tools.build:gradle:3.1.2

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.newtrekwang.test"
        minSdkVersion 18
        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 'com.android.support:appcompat-v7:28.0.0-alpha3'
    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'
}

其中的18，28，com.android.support:appcompat-v7:28.0.0-alpha3，com.android.support:appcompat-v7:28.0.0-alpha3等等

问题

这样直接显示配置的方式，版本号少量还行，多了就有点难受了。

• 构建的时候你要一个一个从别的地方copy版本号
• 加入多个module都依赖了相同的版本号，岂不是改一处，到处都要改
• 一些配置语句太长了

解决

把版本号分在另一个文件，其它地方要用就从文件里拿

例：
1.建一个gradle文件，存放常用的版本号和库名，可以看作存放的都是些键值对，利用gradle的project的扩展可以把这些键值对暂时放进去，然后其他gradle文件要用这些值时通过project获取就行。

version.gradle

// 版本号
ext.deps = [:]
def versions = [:]
versions.arch_core = '1.1.1'
versions.constrant_layout= '1.0.2'
versions.room = '1.1.1'
versions.lifcycle = '1.1.1'
versions.support = "27.1.1"
versions.dagger = "2.15"
versions.junit = "4.12"
versions.espresso = "3.0.1"

versions.rxjava2 = "2.1.3"
versions.rx_android = "2.0.1"

versions.retrofit = "2.3.0"
versions.okhttp3 = "3.9.1"

versions.mockwebserver = "3.8.1"
versions.apache_commons = "2.5"
versions.mockito = "2.7.19"
versions.mockito_all = "1.10.19"
versions.dexmaker = "2.2.0"

versions.glide = "4.7.1"
versions.timber = "4.5.1"

versions.android_gradle_plugin = "3.1.2"



versions.atsl_runner = "1.0.1"
versions.atsl_rules = "1.0.1"
versions.hamcrest = "1.3"
versions.kotlin = "1.2.41"
versions.paging = "1.0.1"
versions.work = "1.0.0-alpha04"
versions.navigation = "1.0.0-alpha01"

versions.arouter = "1.2.2"
versions.arouter_compiler = "1.1.3"


def deps = [:]

// support库
def support = [:]
support.annotations = "com.android.support-annotations:$versions.support"
support.app_compat = "com.android.support:appcompat-v7:$versions.support"
support.recyclerview = "com.android.support:recyclerview-v7:$versions.support"
support.cardview = "com.android.support:cardview-v7:$versions.support"
support.design = "com.android.support:design:$versions.support"
support.v4 = "com.android.support:support-v4:$versions.support"
support.core_utils = "com.android.support:support-core-utils:$versions.support"
support.constrant_layout = "com.android.support.constrant:constrant-layout:$versions.constrant_layout"
deps.support = support

//room相关库
def room  = [:]
room.runtime = "android.arch.persistence.room:runtime:$versions.room"
room.compiler = "android.arch.persistence.room:compiler:$versions.room"
room.rxjava2 = "android.arch.persistence.room:rxjava2:$versions.room"
room.testing = "android.arch.persistence.room:testing:$versions.room"
deps.room = room

//lifecycle相关库
def lifecycle = [:]
lifecycle.runtime = "android.arch.lifecycle:runtime:$versions.lifecycle"
lifecycle.extensions = "android.arch.lifecycle:extensions:$versions.lifecycle"
lifecycle.java8 = "android.arch.lifecycle:common-java8:$versions.lifecycle"
lifecycle.compiler = "android.arch.lifecycle:compiler:$versions.lifecycle"
deps.lifecycle = lifecycle

// arch_core库
def arch_core = [:]
arch_core.testing = "android.arch.core:core-testing:$versions.arch_core"
deps.arch_core = arch_core

//dagger 库
def dagger = [:]
dagger.runtime = "com.google.dagger:dagger:$versions.dagger"
dagger.android = "com.google.dagger:dagger-android:$versions.dagger"
dagger.android_support = "com.google.dagger:dagger-android-support:$versions.dagger"
dagger.compiler = "com.google.dagger:dagger-compiler:$versions.dagger"
dagger.android_support_compiler = "com.google.dagger:dagger-android-processor:$versions.dagger"
deps.dagger = dagger
//glide库
def glide = [:]
glide.runtime = "com.github.bumptech.glide:glide:$versions.glide"
glide.compiler = "com.github.bumptech.glide:compiler:$versions.glide"
deps.glide = glide
// rxjava
deps.rxjava2 = "io.reactivex.rxjava2:rxjava:$versions.rxjava2"
deps.rx_android = "io.reactivex.rxjava2:rxandroid:$versions.rx_android"
// gradle插件
deps.android_gradle_plugin = "com.android.tools.build:gradle:$versions.android_gradle_plugin"
// junit
deps.junit = "junit:junit:$versions.junit"
// ARouter
deps.arouter = "com.alibaba:arouter-api:$versions.arouter"
deps.arouter_compiler = "com.alibaba:arouter-compiler:$versions.arouter_compiler"
// retrofit
deps.retrofit = "com.squareup.retrofit2:retrofit:$versions.retrofit"
deps.okhttp3 = "com.squareup.okhttp3:okhttp:$versions.okhttp3"
deps.okhttp3_interceptor = "com.squareup.okhttp3:logging-interceptor:$versions.okhttp3"
deps.retrofit_converter_gson = "com.squareup.retrofit2:converter-gson:$versions.retrofit"
deps.retrofti_adapter_rxjava = "com.squareup.retrofit2:adapter-rxjava:$versions.retrofit"
ext.deps = deps

def build_versions = [:]
build_versions.min_sdk = 19
build_versions.target_sdk = 28
build_versions.build_tools = "27.0.3"
ext.build_versions = build_versions

2.在根目录的build.gradle的buildscript块中使project应用version.gradle，把version.gradle里的键值对加入扩展，应用后，后面的地方就可以由键名获取键值了，当然键值就是你配置的常用的版本号。

buildscript {
    apply from: 'version.gradle'
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath deps.android_gradle_plugin
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

比如其中deps.android_gradle_plugin就指的是com.android.tools.build:gradle:versions.android_gradle_plugin，然后versions.android_gradle_plugin指的是3.1.2

同样的道理,一个libModule的build.gradle就可以配置为这样

apply plugin: 'com.android.library'

android {
    compileSdkVersion build_versions.target_sdk
    buildToolsVersion build_versions.build_tools

    defaultConfig {
        minSdkVersion build_versions.min_sdk
        targetSdkVersion build_versions.target_sdk
        versionCode 1
        versionName "1.0"

    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    //support
    api deps.support.app_compat
    api deps.support.recyclerview
    api deps.support.cardview
    api deps.support.design
    api deps.support.v4
    api deps.support.core_utils
    //junit
    testImplementation deps.junit
    //rxJava
    api deps.rxjava2
    api deps.rx_android
    // net
    api deps.retrofit
    api deps.okhttp3
    api deps.okhttp3_interceptor
    api deps.retrofit_converter_gson
    api deps.retrofti_adapter_rxjava

    //dagger2
    api deps.dagger.runtime
    annotationProcessor deps.dagger.compiler
}

要改版本号就在version.gradle里改，而且可以在version.gradle尽可能多的版本号或库名字，下次新建项目，直接copy version.gradle进去应用就可以了，不必再到处查库名和版本号