Detailed three gradle files in Android project

Foreword
When using Android studio to develop Android projects, it is necessary to contact gradle, such as introducing dependencies, configuring signature information, and so on. When we create a new project, Android studio will help us create three Gradle files by default, one settings.gradle file, two build.gradle files, and the build.gradle file should not be placed in the root directory and module directory of the project project. Let's uncover the mystery of Gradle.

First look at the file directory structure of the new studio project:



settings.gradle
The role of settings.gradle is that after some modules are included, they need to be declared here:

include ': app'
include ': app', ': demo'
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Multiple modules are separated by ",". The settings.gradle file will be executed during the initialization period.

build.gradle file in the project root directory
The gradle file is a common property of all modules defined in this project, and it contains two methods by default:

buildscript {

    repositories {
        google ()
        jcenter ()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.0-beta2'
    }
}

allprojects {
    repositories {
        google ()
        jcenter ()
    }
}
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The buildscript method defines global related properties, and the repositories define jcenter as a repository. A repository represents the source of your dependencies, such as a maven repository. dependencies are used to define the build process. This means that you should not define the dependencies of submodules in this method body. You only need to define the default Android plugin, because this plugin allows you to execute related Android tasks.

The allprojects method can be used to define the default properties of each module. You can not only limit the default configuration. In the future, you can create tasks in the allprojects method body. These tasks will be visible in all modules.

build.gradle file in module directory
The gradle file in the module module only works for this module, and it can override any parameters from the gradle file in the root directory. When writing programs, sometimes we need mobile phones compatible with different system versions for real machine testing, so sometimes we need to modify the version number of the SDK or other things. At this time we need to understand the build.gradle file. The module file should look like this:

apply plugin: 'com.android.application' // Describes the type of module, com.android.application is the program, and the package is .apk. com.android.library is a library, and the package is .aar.
  android
  {
      compileSdkVersion 25 // Compiled SDK version
      buildToolsVersion "25.0.0" // Compiled Tools version
      defaultConfig
      {//default allocation
          applicationId "com.test" // Application package name
          minSdkVersion 14 // Minimum supported version
          targetSdkVersion 22 // Supported target versions
          versionCode 1 // version number
          versionName "1.0.0" // version name
      }

      sourceSets {// directory points to configuration
          main
          {
              manifest.srcFile 'AndroidManifest.xml' // Specify AndroidManifest file
              java.srcDirs = ['src'] // Specify the source directory
              resources.srcDirs = ['src'] // Specify the source directory
              aidl.srcDirs = ['src'] // Specify the source directory
              renderscript.srcDirs = ['src'] // Specify the source directory
              res.srcDirs = ['res'] // Specify the resource directory
              assets.srcDirs = ['assets'] // Specify the assets directory
              jniLibs.srcDirs = ['libs'] // Specify the lib library directory
          }
          debug.setRoot ('build-types / debug') // Specify the path of debug mode
          release.setRoot ('build-types / release') // Specify the path of the release mode
      }

      signingConfigs
      {// Signing configuration
          release
          {// Release signature configuration
              storeFile file ("E: /test.jks") // Key file path
              storePassword "123" // Key file password
              keyAlias "test" // key alias
              keyPassword "123" // key password
          }
          debug
          {// debug version signature configuration
              storeFile file ("test.jks")
              storePassword "123"
              keyAlias "test"
              keyPassword "123"
          }
      }

      buildTypes
      {// build type
          release {// release
              minifyEnabled true // Confusion is on
              proguardFiles getDefaultProguardFile ('proguard-android.txt'), 'proguard-project.txt' // Specify the obfuscation rules file
              signingConfig signingConfigs.release // Set the signing information
          }
          debug {// debug
              signingConfig signingConfigs.release
          }
      }

      packagingOptions
      {
          exclude 'META-INF / ASL2.0'
          exclude 'META-INF / LICENSE'
          exclude 'META-INF / NOTICE'
          exclude 'META-INF / MANIFEST.MF'
      }
      lintOptions
      {
          abortOnError false /// lint terminates error reporting to prevent inexplicable failure during compilation
      }

// android studio 3.0 supports java8 features
compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    lintOptions {// Set skip translation
        disable 'MissingTranslation'
    }

 flavorDimensions "color"

    productFlavors {
        baidu {}
        xiaomi {}
        yyb {}
        huawei {}
    }
    productFlavors.all {
        flavor-> flavor.manifestPlaceholders = [ChannelName: name]
    }

    // Package apk rename
    applicationVariants.all {variant->
        SimpleDateFormat dateFormat = new SimpleDateFormat ("MM-dd")
        def dateFlag = dateFormat.format (new Date ())
        variant.outputs.all {
            def flavorFlag = variant.flavorName
            def newName = "yzb_" + dateFlag + "_v" + variant.versionName + "_" + variant.versionCode + "_" + flavorFlag + ".apk"
            outputFileName = newName
        }
    }
  }

  dependencies

  {
      compile fileTree (dir: 'libs', exclude: ['android-support * .jar'], include: ['* .jar']) // Compile .jar files in the lib directory
      compile project (': demo') // Compile additional project
     // glide image loading frame
      compile 'com.github.bumptech.glide: glide: 3.7.0'
  }
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This is my understanding of Gradle in the Android project. If there is any deficiency, please leave a message to correct me, thank you ~~
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Copyright statement: This article is the original article of the CSDN blogger "fyjc_wlj", which follows the CC 4.0 BY-SA copyright agreement.