学步园

1、新建资源项目，如mediatek，目录结构：（和其他app一样，因为只要资源，不需要src）

目录存放到framework/base/core/mediatek

res
Android.mk

AndroidManifest.xml

2、.Android.mk内容：

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_PACKAGE_NAME := mediatek-res
LOCAL_CERTIFICATE := platform
# Tell aapt to create “extending (non-application)” resource IDs,
# since these resources will be used by many apps.
LOCAL_AAPT_FLAGS := -x
LOCAL_MODULE_TAGS := optional
# Install this alongside the libraries.
LOCAL_MODULE_PATH := $(TARGET_OUT_JAVA_LIBRARIES)
# Create package-export.apk, which other packages can use to get
# PRODUCT-agnostic resource data like IDs and type definitions.
LOCAL_EXPORT_PACKAGE_RESOURCES := true
LOCAL_BUILDING_ITFUN_RES := true
include $(BUILD_PACKAGE)
# define a global intermediate target that other module may depend on.
.PHONY: mediatek-res-package-target

mediatek-res-package-target: $(LOCAL_BUILT_MODULE)

3.AndroidManifest.xml写法与app一样，这里的包名为package="mediatek"
android:sharedUserId="android.uid.system"

4.修改build/core下package.mk文件

1) 找到resource_export_package := $(intermediates.COMMON)/package-export.apk 行
下方添加：
# ITFUN change begin: ensure framework-res is built before building mediatek-res
ifeq ($(LOCAL_BUILDING_ITFUN_RES), true)
$(resource_export_package): $(call intermediates-dir-for,APPS,framework-res,,COMMON)/src/R.stamp
endif
# ITFUN change end: ensure framework-res is built before building mediatek-res

2)    找到 else # LOCAL_SDK_VERSION 行
下方添加：
# ITFUN change begin: ensure itfun-res is linked as dependency
ifeq ($(LOCAL_BUILDING_ITFUN_RES), true) 
itfun_res_package_export := 
itfun_res_package_export_deps := 
else 
itfun_res_package_export := \
	$(call intermediates-dir-for,APPS,mediatek-res,,COMMON)/package-export.apk
itfun_res_package_export_deps := \
	$(dir $(mediatek_res_package_export))src/R.stamp
endif
# INTUN change end
5、修改framework/base 下Android.mk 文件
framework_res_source_path := APPS/framework-res_intermediates/src
#***************************************************************
# add other-framework-res 
mediatek_res_source_path := APPS/mediatek-res_intermediates/src


LOCAL_INTERMEDIATE_SOURCES := \
            $(framework_res_source_path)/android/R.java \
            $(framework_res_source_path)/android/Manifest.java \
            $(framework_res_source_path)/com/android/internal/R.java \
            $(mediatek_res_source_path)/mediatek/R.java \
            $(mediatek_res_source_path)/mediatek/Manifest.java \
            $(mediatek_res_source_path)/com/mediatek/internal/R.java


# Make sure that R.java and Manifest.java are built before we build
# the source for this library.
framework_res_R_stamp := \
    $(call intermediates-dir-for,APPS,framework-res,,COMMON)/src/R.stamp
mediatek_res_R_stamp := \
        $(call intermediates-dir-for,APPS,mediatek-res,,COMMON)/src/R.stamp
    
$(full_classes_compiled_jar): $(framework_res_R_stamp) $(mediatek_res_R_stamp)

# Make sure that framework-res is installed when framework is.
$(LOCAL_INSTALLED_MODULE): | $(dir $(dir $(LOCAL_INSTALLED_MODULE))mediatek-res.apk)framework-res.apk 


4、修改frameworks/base/libs/utils/AssertManage.cpp文件
a 找到static const char* kSystemAssets = "framework/framework-res.apk";行
下方添加static const char* kItfunAssets = "framework/mediatek-res.apk";
b addDefaultAssets 函数改为：
bool AssetManager::addDefaultAssets()
{
    const char* root = getenv("ANDROID_ROOT");
    LOG_ALWAYS_FATAL_IF(root == NULL, "ANDROID_ROOT not set");

    String8 path(root);
    path.appendPath(kSystemAssets);

    if(!addAssetPath(path, NULL)) {
        return false;
    }

    String8 path2(root);
    path2.appendPath(kItfunAssets);
    return addAssetPath(path2, NULL);
}
5、修改frameworks/base/services/java/com/android/server/PackageManagerService.java文件
找到libFiles.add(mFrameworkDir.getPath() + "/framework-res.apk");行
下方添加
libFiles.add(mFrameworkDir.getPath() + "/mediatek-res.apk"); 
6、最后make clobber 重新make ,完成后只需在代码里使用 mediatek.R.XX就可以调用了



7.如果需要在layout文件夹的xml中通过@mediatek：drawable/bg来引用资源的话，需要修改aapt工具，
aapt工具有参数来-I来指定当前编译的模块的所依赖的其他模块资源，为了能够实现全编译成功，应该给make命令时，默认
加上-I ***，所以这里采用修改源码的方式实现；

首先找到aapt的源码：framework/base/tools/aapt

修改Main.cpp文件：
添加常量如下：
static char *mm = "源码目录/out/target/common/obj/APPS/mediatek-res_intermediates/package-export.apk";
char *mediatek_res = "frameworks/base/core/mediatek/res";
int flag = 0;

在case ‘I’中，末尾添加
if(flag){
 convertPath(mm);
 bundle.addPackageInclude(mm);
}

在case ‘S’中，末尾添加
flag = strcmp(argv[0],mediatek_res);



总结：这样的话，就可以实现资源分离，不仅可以在代码中通过R.drawable.bg引用，
也可以在xml文件中通过@mediatek:drawable/bg

注意：如果发现全编译时通不过，报错的话，需要在所报错的模块的mk文件中添加LOCAL_BUILDING_ITFUN_RES=true