编译时替换资源 - Android重叠包与资源合并一见

Usage:   aapt l[ist] [-v] [-a] file.{zip,jar,apk}     List contents of Zip-compatible archive.     aapt d[ump] [--values] [--include-meta-data] WHAT file.{apk} [asset [asset ...]]     ...     aapt p[ackage] [-d][-f][-m][-u][-v][-x][-z][-M AndroidManifest.xml] \          ...          [--utf16] [--auto-add-overlay] \          ...          [-S resource-sources [-S resource-sources ...]] \          [-F apk-file] [-J R-file-dir] \          ...       Package the android resources.  It will read assets and resources that are     supplied with the -M -A -S or raw-files-dir arguments.  The -J -P -F and -R     options control which files are output.    ...     Modifiers:     ...     # 特别说明下，这就是前一篇我们说到的include的base set啦，比如android.jar     -I  add an existing package to base include set     ...     # overlay通过-S指定，可以指定多个目录，     -S  directory in which to find resources.  Multiple directories will be scanned         and the first match found (left to right) will take precedence.     ...     # 自动添加overlays包里的资源     --auto-add-overlay         Automatically add resources that are only in overlays.     ...

aapt package \  -M AndroidManifest.xml \  -m -J gen \  -S src/com/example/res \  -S src/com/example/ui/res

假如我们有如上的aapt命令输入，那么当 src/com/example/res 与 src/com/example/ui/res 有相同资源的时候，就会使用前者的，这里对资源替换的粒度是resource而不是文件，比如两个文件夹的values/string.xml都有对同一个string id的描述，最后就会使用前者的字符串。

然后我们再来看看 --auto-add-overlay 有什么用，

假如我们在 src/com/example/ui/res 定义了资源string a，但是在 src/com/example/res 却没有这个string，那就会报错，因为基础包里是没有那个资源的，这时候就需要加上 --auto-add-overlay ，于是就会自动把新的资源都添加进去。

overlay大致就是这么一回事啦。

Gradle实践

aaptOptions

google的官方文档简直说了和没说一样。还是自己来吧，用AS的模板新建一个Testapp工程，随便建两个res文件夹，各放两个strings.xml，结构为：

├── res  │   ├── drawable  │   ├── layout  │   │   ├── activity_main.xml  │   │   └── content_main.xml  │   ├── menu  │   │   └── menu_main.xml  │   ├── mipmap-xxxhdpi  │   │   └── ic_launcher.png  │   └── values  │       ├── colors.xml  │       ├── dimens.xml  │       ├── strings.xml  │       └── styles.xml  ├── res2  │   └── values  │       └── strings.xml  └── res3      └── values          └── strings.xml

res2和res3分别定义了一个string hehe ，value分别为 hehe res2 和 hehe res3 。

content_main.xml的TextView使用了 hehe （原来就是那个Hello World）。当然这里as会报错，因为res2和res3并没有标示为资源文件夹。

在module的build.gradle里:

android {    ...    aaptOptions {        additionalParameters '-S',                '/Users/yifan/dev/github/Testapp/app/src/main/res3',                '-S',                '/Users/yifan/dev/github/Testapp/app/src/main/res2',                '--auto-add-overlay'        noCompress 'foo', 'bar'        ignoreAssetsPattern '!.svn:!.git:!.ds_store:!*.scc:.*:<dir>_*:!CVS:!thumbs.db:!picasa.ini:!*~'    }    ...  }

All input files are considered out-of-date for incremental task ':app:processDebugResources'.  Starting process 'command '/Users/yifan/dev/sdk/adt-bundle-mac-sdk/build-tools/23.0.2/aapt''. Working directory: /Users/yifan/dev/github/Testapp/app Command: /Users/yifan/dev/sdk/adt-bundle-mac-sdk/build-tools/23.0.2/aapt package -f --no-crunch -I /Users/yifan/dev/sdk/adt-bundle-mac-sdk/platforms/android-23/android.jar -M /Users/yifan/dev/github/Testapp/app/build/intermediates/manifests/full/debug/AndroidManifest.xml -S /Users/yifan/dev/github/Testapp/app/build/intermediates/res/merged/debug -A /Users/yifan/dev/github/Testapp/app/build/intermediates/assets/debug -m -J /Users/yifan/dev/github/Testapp/app/build/generated/source/r/debug -F /Users/yifan/dev/github/Testapp/app/build/intermediates/res/resources-debug.ap_ --debug-mode --custom-package cn.zhaiyifan.testapp -0 apk -S /Users/yifan/dev/github/Testapp/app/src/main/res2 --output-text-symbols /Users/yifan/dev/github/Testapp/app/build/intermediates/symbols/debug  Successfully started process 'command '/Users/yifan/dev/sdk/adt-bundle-mac-sdk/build-tools/23.0.2/aapt''  /Users/yifan/dev/github/Testapp/app/build/intermediates/res/merged/debug/values-af/values-af.xml:3 : AAPT: Resource at abc_action_bar_home_description appears in overlay but not in the base package; use <add-resource> to add.  ...  ...各种类似报错  /usr/local/google/buildbot/src/googleplex-android/mnc-supportlib-release/frameworks/support/v7/appcompat/res/color/switch_thumb_material_light.xml:19 : AAPT: No resource found that matches the given name (at 'color' with value '@color/switch_thumb_normal_material_light').    :app:processDebugResources FAILED  :app:processDebugResources (Thread[main,5,main]) completed. Took 10.493 secs.

android.sourceSets { main.res.srcDirs = ['src/main/res', 'src/main/res2'] }

android {      compileSdkVersion 23      buildToolsVersion "23.0.2"        defaultConfig {          applicationId "cn.zhaiyifan.testapp"          minSdkVersion 14          targetSdkVersion 23          versionCode 1          versionName "1.0"      }      buildTypes {          release {              minifyEnabled false              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'          }      }      aaptOptions {          additionalParameters '-S',                  '/Users/yifan/dev/github/Testapp/app/src/main/res3',                  '-S',                  '/Users/yifan/dev/github/Testapp/app/src/main/res2',                  '--auto-add-overlay'          noCompress 'foo', 'bar'          ignoreAssetsPattern '!.svn:!.git:!.ds_store:!*.scc:.*:<dir>_*:!CVS:!thumbs.db:!picasa.ini:!*~'      }      android.sourceSets {          main.res.srcDirs = ['src/main/res', 'src/main/res2']      }  }