Android gradle groovy改为kotlin总结

前言： Android gradle 的 Groovy 转 Kotlin 的难点在于groovy非常不规范，以为是一个变量其实是一个方法，以为是方法其实是一个一个字符串，koltin提供了更严格的语法。改为kotlin之后最大的变化就是扩展字段了，和groovy的语法完全不一样，需要好好了解学习一下，本文也会讲到。

下面是我对自己的项目改造总结，使用的gradle版本是gradle-7.3.3，agp版本是7.2.1。

文件重命名

改造前首先要将原来的gradle文件加上‘kts’后缀，如build.gradle改为build.gradle.kts，kts是Kotlin Script的缩写。重命名后AndroidStudio会自动识别为kotlin dsl。

项目的build.gradle

groovy

// Top-level build file where you can add configuration options common to all sub-projects/modules.
apply from: 'config.gradle'
apply plugin: 'com.alibaba.arouter'buildscript {repositories {maven { url "https://maven.aliyun.com/repository/public" }}dependencies {classpath 'com.android.tools.build:gradle:7.2.1'classpath "com.alibaba:arouter-register:1.0.2"}
}allprojects {repositories {maven { url "https://maven.aliyun.com/repository/public" }}configurations.all {// fix 依赖冲突resolutionStrategy.force "androidx.appcompat:appcompat:1.4.2"resolutionStrategy.force "androidx.recyclerview:recyclerview:1.2.1"}
}task clean(type: Delete) {delete rootProject.buildDir
}

kotlin

apply(from = "config.gradle.kts")
apply(plugin = "com.alibaba.arouter")buildscript {repositories {maven("https://maven.aliyun.com/repository/public")}dependencies {classpath(libs.android.gradlePlugin)classpath(libs.greendao.gradlePlugin)}
}allprojects {repositories {maven("https://maven.aliyun.com/repository/public")}configurations.all {resolutionStrategy.force("androidx.appcompat:appcompat:1.4.2")resolutionStrategy.force("androidx.recyclerview:recyclerview:1.2.1")}
}tasks.create<Delete>("clean") {delete(rootProject.buildDir)
}

module的build.gradle

groovy

apply plugin: 'com.android.application'
apply plugin: 'org.greenrobot.greendao'android {compileSdk = libs.versions.compileSdk.get().toInteger()ndkVersion = libs.versions.ndkVersion.get()defaultConfig {applicationId "com.myapp.sample"minSdkVersion(libs.versions.minSdk.get().toInteger())targetSdkVersion(libs.versions.targetSdk.get().toInteger())versionCode 1versionName "1.0"testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"multiDexEnabled trueexternalNativeBuild {cmake {cppFlags ""abiFilters "arm64-v8a", "armeabi-v7a", "x86"}}}signingConfigs {app {keyAlias 'appkey'keyPassword '******'storeFile file('key.jks')storePassword '******'}}buildTypes {release {minifyEnabled truezipAlignEnabled truesigningConfig signingConfigs.appproguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro', 'proguard-android.pro', 'proguard-third-libs.pro'}debug {minifyEnabled falsedebuggable truesigningConfig signingConfigs.app}}compileOptions {sourceCompatibility JavaVersion.VERSION_1_8targetCompatibility JavaVersion.VERSION_1_8}buildFeatures {dataBinding true}greendao {schemaVersion 1}externalNativeBuild {cmake {path "src/main/cpp/CMakeLists.txt"version "3.10.2"}}lintOptions {abortOnError false}
}dependencies {configurations.all {// check for updates every buildresolutionStrategy.cacheChangingModulesFor 30, 'seconds'}implementation(libs.glide)annotationProcessor(libs.glide.compiler)implementation(libs.androidx.constraintlayout)implementation(project(':easyPhotos'))implementation(libs.google.zxing.core) {exclude group: 'com.google.guava'}
}

kotlin

plugins {id("com.android.application")id("org.greenrobot.greendao")
}
android {compileSdk = libs.versions.compileSdk.get().toInt()ndkVersion = libs.versions.ndkVersion.get()defaultConfig {applicationId = "com.myapp.sample"minSdk = libs.versions.minSdk.get().toInt()targetSdk = libs.versions.targetSdk.get().toInt()versionCode = 1versionName = "1.0"testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"multiDexEnabled = trueexternalNativeBuild {cmake {cppFlags += listOf()abiFilters += listOf("arm64-v8a", "armeabi-v7a", "x86")}}}signingConfigs {create("release") {keyAlias = "appkey"keyPassword = "******"storeFile = file("key.jks")storePassword = "******"}}buildTypes {release {isMinifyEnabled = trueisZipAlignEnabled = truesigningConfig = signingConfigs.getByName("release")proguardFiles(getDefaultProguardFile("proguard-android.txt"),"proguard-rules.pro","proguard-android.pro","proguard-third-libs.pro")}debug {isMinifyEnabled = falseisDebuggable = truesigningConfig = signingConfigs.getByName("release")}}compileOptions {sourceCompatibility = JavaVersion.VERSION_1_8targetCompatibility = JavaVersion.VERSION_1_8}buildFeatures {dataBinding = true}greendao {schemaVersion = 1}externalNativeBuild {cmake {path("src/main/cpp/CMakeLists.txt")version = "3.10.2"}}lintOptions {isAbortOnError = false}}dependencies {configurations.all {// check for updates every buildresolutionStrategy.cacheChangingModulesFor(30, TimeUnit.SECONDS)}implementation(libs.glide)annotationProcessor(libs.glide.compiler)implementation(project(":easyPhotos"))implementation(libs.androidx.constraintlayout)implementation(libs.google.zxing.core) {//也可这么写  exclude(group = "com.google.guava")exclude(mapOf("group" to "com.google.guava"))}
}

关于扩展字段

一、首先是新增扩展字段

groovy要新增扩展字段只需在ext{}里面随便加字段，kotlin改为用extra，语法也做了改变，具体看下面例子：

groovy

//这里在项目根目录的user.gradle下新增用户名和密码
ext {username = 'JohnSnow'password = 'abcxxx'
}

kotlin 有三种写法

// 写法一，如果不写rootProject默认会加上当前的project
rootProject.extra.apply {set("username", "JohnSnow")set("password", "abcxxx")
}// 写法二
val username : String by rootProject.extra("JohnSnow")
val password : String by rootProject.extra("abcxxx")// 写法三,大括号里面可以写语句，最后一行是返回值
val username : String by rootProject.extra{val name = "JohnSnow"name
}
val password : String by rootProject.extra{"abcxxx"}

二、使用扩展字段

groovy

def name = rootProject.ext.username
def pwd = rootProject.ext.password

kotlin 有两种使用方式

//方式一,这种方式就是Map的key-value形式
val name = rootProject.extra["username"] as String
val pwd = rootProject.extra["password"] as String//方式二,这是kotlin dsl提供的语法糖，这种方式指定的变量名username必须与extra里的"username"一致，
//且必须指定字段类型（String）
val username: String by rootProject.extra
val password: String by rootProject.extra

关于上传到maven的写法区别

上传到maven有两种写法，

一种是直接在当前要上传的library模块的build.gradle里写上传脚步代码

这种方式自带模块的project环境，kotlin dsl做了一些适配，写法会更简单些

第二种是放到一个单独的maven.gradle里统一处理，这种方式适用于有很多个library需要上传的情况，不用每个模块都写一遍上传脚本；

这种方式是在单独的gradle里编写没有自带project的环境，所以第二种方式的写法会复杂一些，而且没有代码提示。

一、在library模块编写

groovy

apply plugin: 'com.android.library'android {...略//提交到顺丰maven所需的配置publishing {singleVariant('release') {withSourcesJar()}}
}
// maven插件
apply plugin: 'maven-publish'afterEvaluate {def GROUP_ID = "com.free.sdk"def ARTIFACT_ID = "wo-util"def VERSION = "1.0.0"publishing {publications {//mylib名字随意mylib(MavenPublication) {from components.releasegroupId = GROUP_IDartifactId = ARTIFACT_IDversion = VERSIONpom.withXml {println "!!!!>>>>>> ${project.name} 要上传的版本-> $groupId:$artifactId:$version"println "!!!!>>>>>> ${project.name} 依赖的包："configurations.implementation.allDependencies.each {if (it.version != "unspecified") { // 过滤项目内library引用println "   " + it.group + ":" + it.name + ":" + it.version}}}}}//需要发布的目标仓库repositories {maven {url = rootProject.extra["mavenUrl"] as Stringcredentials {//密码认证username = rootProject.extra["username"] as Stringpassword = rootProject.extra["password"] as String}}}}
}

kotlin

plugins {id("com.android.library")//注意maven插件要写在头部`maven-publish`
}android {...略//提交到顺丰maven所需的配置publishing {singleVariant("release") {withSourcesJar()}}
}afterEvaluate {val GROUP_ID = "com.free.sdk"val ARTIFACT_ID = "wo-util"val VERSION = "1.0.0"publishing {publications {//mylib名字随意register<MavenPublication>("mylib") {from(components["release"])groupId = GROUP_IDartifactId = ARTIFACT_IDversion = VERSIONpom.withXml {println("!!!!>>>>>> ${project.name} 要上传的版本-> $groupId:$artifactId:$version")println("!!!!>>>>>> ${project.name} 依赖的包：")configurations.implementation.allDependencies.forEach { dependency ->if (dependency.version != "unspecified") {println("   ${dependency.group}:${dependency.name}:${dependency.version}")}}}}}repositories {maven {setUrl(rootProject.extra["mavenUrl"] as String)credentials {username = rootProject.extra["username"] as Stringpassword = rootProject.extra["password"] as String}}}}
}

二、在maven.gradle里统一处理

在library的build.gradle.kts里引入maven.gradle

plugins {id("com.android.library")
}
apply(from = "${rootProject.rootDir}/maven.gradle.kts")

maven.gradle.kts里的代码

import org.gradle.api.publish.PublishingExtensionapply(plugin = "maven-publish")val libraries: Map<String, Map<String, String>> by rootProject.extra
val library = libraries[project.name]!!
val sonatype: Map<String, String> by rootProject.extraval repositoryUrl = if ((library["version"] as String).endsWith("SNAPSHOT")) {sonatype["snapshotUrl"]!!
} else {sonatype["releaseUrl"]!!
}//publishing报错， 改为 configure<PublishingExtension>原因：
//https://stackoverflow.com/questions/54654376/why-is-publishing-function-not-being-found-in-my-custom-gradle-kts-file-within
configure<PublishingExtension> {// --------不同点1️⃣publications {register<MavenPublication>("mylib") {afterEvaluate { from(components["release"]) }groupId = rootProject.extra["groupId"] as StringartifactId = library["artifactId"]version = library["version"]pom.withXml {println("!!!!>>>>>> ${project.name} 要上传的版本-> $groupId:$artifactId:$version")println("!!!!>>>>>> ${project.name} 依赖的包：")configurations {"implementation" {// --------不同点2️⃣allDependencies.forEach {if (it.version != "unspecified") { // 过滤项目内library引用println("   " + it.group + ":" + it.name + ":" + it.version)}}}}}}}repositories {maven {setUrl(repositoryUrl)credentials {username = sonatype["username"]password = sonatype["password"]}}}
}