Android Studio中的Module，Facet

詳細內容請參看 http://www.jetbrains.com/idea/webhelp/facet.html

以及 http://www.jetbrains.com/idea/webhelp/android-facet-page.html

那裏有android studio的詳細使用說明。

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A module is a discrete unit of functionality which you can compile, run, test and debug independently.

Modules contain everything that is required for their specific tasks: source code, build scripts, unit tests, deployment descriptors, and documentation. However, modules exist and are functional only in the context of a project.

Configuration information for a module is stored in a .iml module file. By default, such a file is located in the module's content root folder.

Development teams, normally, share the .iml module files through version control.

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Facets represent various frameworks, technologies and languages used in a module. They let IntelliJ IDEA know how to treat the module contents and thus ensure conformity with the corresponding frameworks and technologies.

Using facets enables you to download and configure the necessary framework components, have various descriptors generated automatically and stored in proper locations, and so on.

Most facets may be added to a module irrespective of whether other facets exist.

There are also facets that extend other facets. Such facets are possible only if a module has their parent facet. For more information, seeAvailable Facets and Their Dependencies.

 

Library module

Select this check box to enable using the module as library project so Android application projects can reference its source code and resources.

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在用android studio時，每一個module都要正確第設置上面2方面的內容才能正確運行，否則系統不認爲你是android程序，或是運行報錯。module比較好理解，facet是什麼呢？簡單理解，facet有點想xcode中的target，就是對module資源的利用配置。在一個module中是容許多個facet存在的，每一個facet會對module的資源進行不一樣的應用，好比如下代碼是一個android studio 建立的一個module的配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<module external.linked.project.path="$MODULE_DIR$" external.root.project.path="$MODULE_DIR$/.." external.system.id="GRADLE" external.system.module.group="MyApplication" external.system.module.version="unspecified" type="JAVA_MODULE" version="4">
  <component name="FacetManager">
    <facet type="android-gradle" name="Android-Gradle">
      <configuration>
        <option name="GRADLE_PROJECT_PATH" value=":app" />
      </configuration>
    </facet>
    <facet type="android" name="Android">
      <configuration>
        <option name="SELECTED_BUILD_VARIANT" value="debug" />
        <option name="ASSEMBLE_TASK_NAME" value="assembleDebug" />
        <option name="COMPILE_JAVA_TASK_NAME" value="compileDebugJava" />
        <option name="ASSEMBLE_TEST_TASK_NAME" value="assembleDebugTest" />
        <option name="SOURCE_GEN_TASK_NAME" value="generateDebugSources" />
        <option name="ALLOW_USER_CONFIGURATION" value="false" />
        <option name="MANIFEST_FILE_RELATIVE_PATH" value="/src/main/AndroidManifest.xml" />
        <option name="RES_FOLDER_RELATIVE_PATH" value="/src/main/res" />
        <option name="RES_FOLDERS_RELATIVE_PATH" value="file://$MODULE_DIR$/src/main/res" />
        <option name="ASSETS_FOLDER_RELATIVE_PATH" value="/src/main/assets" />
      </configuration>
    </facet>
  </component>
  <component name="NewModuleRootManager" inherit-compiler-output="false">
    <output url="file://$MODULE_DIR$/build/classes/debug" />
    <exclude-output />
    <content url="file://$MODULE_DIR$">
      <sourceFolder url="file://$MODULE_DIR$/build/source/r/debug" isTestSource="false" generated="true" />
      <sourceFolder url="file://$MODULE_DIR$/build/source/aidl/debug" isTestSource="false" generated="true" />
      <sourceFolder url="file://$MODULE_DIR$/build/source/buildConfig/debug" isTestSource="false" generated="true" />
      <sourceFolder url="file://$MODULE_DIR$/build/source/rs/debug" isTestSource="false" generated="true" />
      <sourceFolder url="file://$MODULE_DIR$/build/res/rs/debug" type="java-resource" />
      <sourceFolder url="file://$MODULE_DIR$/build/source/r/test/debug" isTestSource="true" generated="true" />
      <sourceFolder url="file://$MODULE_DIR$/build/source/aidl/test/debug" isTestSource="true" generated="true" />
      <sourceFolder url="file://$MODULE_DIR$/build/source/buildConfig/test/debug" isTestSource="true" generated="true" />
      <sourceFolder url="file://$MODULE_DIR$/build/source/rs/test/debug" isTestSource="true" generated="true" />
      <sourceFolder url="file://$MODULE_DIR$/build/res/rs/test/debug" type="java-test-resource" />
      <sourceFolder url="file://$MODULE_DIR$/src/debug/res" type="java-resource" />
      <sourceFolder url="file://$MODULE_DIR$/src/debug/resources" type="java-resource" />
      <sourceFolder url="file://$MODULE_DIR$/src/debug/aidl" isTestSource="false" />
      <sourceFolder url="file://$MODULE_DIR$/src/debug/assets" isTestSource="false" />
      <sourceFolder url="file://$MODULE_DIR$/src/debug/java" isTestSource="false" />
      <sourceFolder url="file://$MODULE_DIR$/src/debug/jni" isTestSource="false" />
      <sourceFolder url="file://$MODULE_DIR$/src/debug/rs" isTestSource="false" />
      <sourceFolder url="file://$MODULE_DIR$/src/main/res" type="java-resource" />
      <sourceFolder url="file://$MODULE_DIR$/src/main/resources" type="java-resource" />
      <sourceFolder url="file://$MODULE_DIR$/src/main/aidl" isTestSource="false" />
      <sourceFolder url="file://$MODULE_DIR$/src/main/assets" isTestSource="false" />
      <sourceFolder url="file://$MODULE_DIR$/src/main/java" isTestSource="false" />
      <sourceFolder url="file://$MODULE_DIR$/src/main/jni" isTestSource="false" />
      <sourceFolder url="file://$MODULE_DIR$/src/main/rs" isTestSource="false" />
      <sourceFolder url="file://$MODULE_DIR$/src/androidTest/res" type="java-test-resource" />
      <sourceFolder url="file://$MODULE_DIR$/src/androidTest/resources" type="java-test-resource" />
      <sourceFolder url="file://$MODULE_DIR$/src/androidTest/aidl" isTestSource="true" />
      <sourceFolder url="file://$MODULE_DIR$/src/androidTest/assets" isTestSource="true" />
      <sourceFolder url="file://$MODULE_DIR$/src/androidTest/java" isTestSource="true" />
      <sourceFolder url="file://$MODULE_DIR$/src/androidTest/jni" isTestSource="true" />
      <sourceFolder url="file://$MODULE_DIR$/src/androidTest/rs" isTestSource="true" />
      <excludeFolder url="file://$MODULE_DIR$/build/apk" />
      <excludeFolder url="file://$MODULE_DIR$/build/assets" />
      <excludeFolder url="file://$MODULE_DIR$/build/bundles" />
      <excludeFolder url="file://$MODULE_DIR$/build/classes" />
      <excludeFolder url="file://$MODULE_DIR$/build/dependency-cache" />
      <excludeFolder url="file://$MODULE_DIR$/build/incremental" />
      <excludeFolder url="file://$MODULE_DIR$/build/libs" />
      <excludeFolder url="file://$MODULE_DIR$/build/manifests" />
      <excludeFolder url="file://$MODULE_DIR$/build/res" />
      <excludeFolder url="file://$MODULE_DIR$/build/symbols" />
      <excludeFolder url="file://$MODULE_DIR$/build/tmp" />
    </content>
    <orderEntry type="jdk" jdkName="Android API 19 Platform" jdkType="Android SDK" />
    <orderEntry type="sourceFolder" forTests="false" />
    <orderEntry type="library" exported="" name="appcompat-v7-19.1.0" level="project" />
    <orderEntry type="library" exported="" name="support-v4-19.1.0" level="project" />
  </component>
</module>

這裏就有2個facet，第一個是gradule使用的facet，第二個是編譯module時使用的facet。

在使用intellij時，咱們有如下的界面配置facet：

多是facet的功能被gradle代替了，若是你用android studio建立基於gradule的android工程，只有如下的界面：

facet的配置被省略了，若是你想更改，必須到相應的iml文件中去更改。