开始新项目时,Android Studio 会自动创建其中的部分文件(如下图所示),并为它们填充合理的默认值。
settings.gradle
文件位于项目根目录,用于指示 Gradle 在构建应用时应将哪些模块包括在内。对大多数项目而言,该文件很简单,只包括以下内容:
include ‘:app’
不过,多模块项目需要指定应包括在最终构建之中的每个模块。
顶级 build.gradle
文件位于项目根目录,用于定义适用于项目中所有模块的构建配置。默认情况下,这个顶级构建文件使用 buildscript {}
代码块来定义项目中所有模块共用的 Gradle 存储区和依赖项。以下代码示例描述的默认设置和 DSL 元素可在新建项目后的顶级 build.gradle
文件中找到。
/**
* The buildscript {} block is where you configure the repositories and
* dependencies for Gradle itself--meaning, you should not include dependencies
* for your modules here. For example, this block includes the Android plugin for
* Gradle as a dependency because it provides the additional instructions Gradle
* needs to build Android app modules.
*/
buildscript {
/**
* The repositories {} block configures the repositories Gradle uses to
* search or download the dependencies. Gradle pre-configures support for remote
* repositories such as JCenter, Maven Central, and Ivy. You can also use local
* repositories or define your own remote repositories. The code below defines
* JCenter as the repository Gradle should use to look for its dependencies.
*/
repositories {
jcenter()
}
/**
* The dependencies {} block configures the dependencies Gradle needs to use
* to build your project. The following line adds Android Plugin for Gradle
* version 3.1.0 as a classpath dependency.
*/
dependencies {
classpath 'com.android.tools.build:gradle:3.1.0'
}
}
/**
* The allprojects {} block is where you configure the repositories and
* dependencies used by all modules in your project, such as third-party plugins
* or libraries. Dependencies that are not required by all the modules in the
* project should be configured in module-level build.gradle files. For new
* projects, Android Studio configures JCenter as the default repository, but it
* does not configure any dependencies.
*/
allprojects {
repositories {
jcenter()
}
}
模块级 build.gradle
文件位于每个
目录,用于配置适用于其所在模块的构建设置。您可以通过配置这些构建设置来提供自定义打包选项(例如附加构建类型和产品风味),以及替换 main/
应用清单或顶级 build.gradle
文件中的设置。
/**
* The first line in the build configuration applies the Android plugin for
* Gradle to this build and makes the android {} block available to specify
* Android-specific build options.
*/
apply plugin: 'com.android.application'
/**
* The android {} block is where you configure all your Android-specific
* build options.
*/
android {
/**
* compileSdkVersion specifies the Android API level Gradle should use to
* compile your app. This means your app can use the API features included in
* this API level and lower.
*
* buildToolsVersion specifies the version of the SDK build tools, command-line
* utilities, and compiler that Gradle should use to build your app. You need to
* download the build tools using the SDK Manager.
*/
compileSdkVersion 26
buildToolsVersion "27.0.3"
/**
* The defaultConfig {} block encapsulates default settings and entries for all
* build variants, and can override some attributes in main/AndroidManifest.xml
* dynamically from the build system. You can configure product flavors to override
* these values for different versions of your app.
*/
defaultConfig {
/**
* applicationId uniquely identifies the package for publishing.
* However, your source code should still reference the package name
* defined by the package attribute in the main/AndroidManifest.xml file.
*/
applicationId 'com.example.myapp'
// Defines the minimum API level required to run the app.
minSdkVersion 15
// Specifies the API level used to test the app.
targetSdkVersion 26
// Defines the version number of your app.
versionCode 1
// Defines a user-friendly version name for your app.
versionName "1.0"
}
/**
* The buildTypes {} block is where you can configure multiple build types.
* By default, the build system defines two build types: debug and release. The
* debug build type is not explicitly shown in the default build configuration,
* but it includes debugging tools and is signed with the debug key. The release
* build type applies Proguard settings and is not signed by default.
*/
buildTypes {
/**
* By default, Android Studio configures the release build type to enable code
* shrinking, using minifyEnabled, and specifies the Proguard settings file.
*/
release {
minifyEnabled true // Enables code shrinking for the release build type.
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
/**
* The productFlavors {} block is where you can configure multiple product
* flavors. This allows you to create different versions of your app that can
* override defaultConfig {} with their own settings. Product flavors are
* optional, and the build system does not create them by default. This example
* creates a free and paid product flavor. Each product flavor then specifies
* its own application ID, so that they can exist on the Google Play Store, or
* an Android device, simultaneously.
*/
productFlavors {
free {
applicationId 'com.example.myapp.free'
}
paid {
applicationId 'com.example.myapp.paid'
}
}
/**
* The splits {} block is where you can configure different APK builds that
* each contain only code and resources for a supported screen density or
* ABI. You'll also need to configure your build so that each APK has a
* different versionCode.
*/
splits {
// Screen density split settings
density {
// Enable or disable the density split mechanism
enable false
// Exclude these densities from splits
exclude "ldpi", "tvdpi", "xxxhdpi", "400dpi", "560dpi"
}
}
}
/**
* The dependencies {} block in the module-level build configuration file
* only specifies dependencies required to build the module itself.
*/
dependencies {
compile project(":lib")
compile 'com.android.support:appcompat-v7:27.1.1'
compile fileTree(dir: 'libs', include: ['*.jar'])
}
Gradle 还包括两个属性文件,位于项目根目录,可用于指定适用于 Gradle 构建工具包本身的设置:
gradle.properties
您可以在其中配置项目范围 Gradle 设置,例如 Gradle 后台进程的最大堆大小。
local.properties
为构建系统配置本地环境属性,例如 SDK 安装路径。由于该文件的内容由 Android Studio 自动生成并且专用于本地开发者环境,因此您不应手动修改该文件,或将其纳入您的版本控制系统。
Android Studio 按逻辑关系将每个模块的源代码和资源分组为源集。模块的 main/
源集包括其所有构建变体共用的代码和资源。其他源集目录为可选项,在您配置新的构建变体时,Android Studio 不会自动为您创建这些目录。不过,创建类似于 main/
的源集有助于让 Gradle 只应在构建特定应用版本时使用的文件和资源井然有序:
src/main/
此源集包括所有构建变体共用的代码和资源。
src/
创建此源集可加入特定构建类型专用的代码和资源。
src/
创建此源集可加入特定产品风味专用的代码和资源。
src/
创建此源集可加入特定构建变体专用的代码和资源。
例如,要生成应用的“完整调试”版本,构建系统需要合并来自以下源集的代码、设置和资源:
src/fullDebug/
(构建变体源集)src/debug/
(构建类型源集)src/full/
(产品风味源集)src/main/
(主源集)可以在 values ——> strings.xml 中添加对应字符串常量,并在本项目中通过 "@string/string_name" 来引用
jni
Welcome
可以在 values ——> colors.xml 中添加对应颜色常量,并在本项目中通过 "@color/color_name" 来引用
#125688
#104a74
#FFFFFF
#FFFFFF
#000000
#c8e8ff
#009688
#00796B
#B2DFDB
#FF9800
#212121
#cbcbcb
#FFFFFF
#BDBDBD