如何在基于Android.mk的Android项目中引入CMake项目？

问题描述 #

我正在构建Android原生项目，当前采用Android.mk进行构建。现需引入两个依赖项目：funchook（依赖capstone），但这两个项目仅提供CMakeLists.txt而非Android.mk，请问是否有方法引入这些CMake项目？

当前项目目录结构：

├── build.gradle
├── jni
│   ├── Android.mk
│   ├── Application.mk
│   ├── example.cpp
│   └── libcxx
└── src
    └── main
        └── AndroidManifest.xml

Android.mk 配置：

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)
LOCAL_MODULE := example
LOCAL_SRC_FILES := example.cpp
LOCAL_STATIC_LIBRARIES := libcxx
LOCAL_LDLIBS := -llog
include $(BUILD_EXECUTABLE)

include jni/libcxx/Android.mk

Application.mk 配置：

APP_ABI      := armeabi-v7a arm64-v8a x86 x86_64
APP_CPPFLAGS := -std=c++17 -fno-exceptions -fno-rtti -fvisibility=hidden -fvisibility-inlines-hidden
APP_STL      := none
APP_PLATFORM := android-21

AndroidManifest.xml 配置：

<?xml version="1.0" encoding="utf-8"?>
<manifest package="native" />

解决方案 #

方法1：通过ndk-build直接调用CMake构建依赖 #

ndk-build（r21及以上版本）支持在Android.mk中调用CMake编译外部项目，生成静态库后直接链接到主项目：

1. 将funchook和capstone源码放到项目jni/thirdparty目录下，结构如下：

   jni/
   └── thirdparty/
       ├── capstone/
       └── funchook/
   

2. 修改主Android.mk，添加依赖编译逻辑：

   LOCAL_PATH := $(call my-dir)
   
   # 编译capstone静态库
   include $(CLEAR_VARS)
   LOCAL_MODULE := capstone
   LOCAL_SRC_FILES := thirdparty/capstone/CMakeLists.txt
   # 传递CMake编译参数，关闭动态库、测试编译
   LOCAL_CMAKE_FLAGS := -DCAPSTONE_BUILD_SHARED=OFF -DCAPSTONE_BUILD_STATIC=ON -DCAPSTONE_BUILD_TESTS=OFF
   include $(BUILD_CMAKE_PROJECT)
   
   # 编译funchook静态库（依赖capstone）
   include $(CLEAR_VARS)
   LOCAL_MODULE := funchook
   LOCAL_SRC_FILES := thirdparty/funchook/CMakeLists.txt
   LOCAL_CMAKE_FLAGS := -DFUNCHOOK_BUILD_SHARED=OFF -DFUNCHOOK_BUILD_STATIC=ON -DFUNCHOOK_USE_CAPSTONE=ON
   LOCAL_STATIC_LIBRARIES := capstone
   include $(BUILD_CMAKE_PROJECT)
   
   # 更新主可执行文件的依赖
   include $(CLEAR_VARS)
   LOCAL_MODULE := example
   LOCAL_SRC_FILES := example.cpp
   LOCAL_STATIC_LIBRARIES := libcxx capstone funchook
   LOCAL_LDLIBS := -llog
   include $(BUILD_EXECUTABLE)
   
   include jni/libcxx/Android.mk
   

方法2：预编译依赖为静态库后引入 #

提前用CMake编译好对应ABI的静态库，再复制到项目中通过Android.mk引用：

1. 用CMake或Android Studio针对每个目标ABI（armeabi-v7a、arm64-v8a等）编译capstone和funchook的静态库（.a文件）。

2. 在项目jni目录下创建libs/[ABI]结构，将对应ABI的静态库放入：

   jni/
   └── libs/
       ├── armeabi-v7a/
       │   ├── libcapstone.a
       │   └── libfunchook.a
       ├── arm64-v8a/
       │   ├── libcapstone.a
       │   └── libfunchook.a
       ├── x86/
       │   ├── libcapstone.a
       │   └── libfunchook.a
       └── x86_64/
           ├── libcapstone.a
           └── libfunchook.a
   

3. 修改Android.mk引入预编译库：

   LOCAL_PATH := $(call my-dir)
   
   # 引入预编译的capstone静态库
   include $(CLEAR_VARS)
   LOCAL_MODULE := capstone
   LOCAL_SRC_FILES := libs/$(TARGET_ABI)/libcapstone.a
   include $(PREBUILT_STATIC_LIBRARY)
   
   # 引入预编译的funchook静态库
   include $(CLEAR_VARS)
   LOCAL_MODULE := funchook
   LOCAL_SRC_FILES := libs/$(TARGET_ABI)/libfunchook.a
   LOCAL_STATIC_LIBRARIES := capstone
   include $(PREBUILT_STATIC_LIBRARY)
   
   # 更新主可执行文件依赖
   include $(CLEAR_VARS)
   LOCAL_MODULE := example
   LOCAL_SRC_FILES := example.cpp
   LOCAL_STATIC_LIBRARIES := libcxx capstone funchook
   LOCAL_LDLIBS := -llog
   include $(BUILD_EXECUTABLE)
   
   include jni/libcxx/Android.mk
   

方法3：迁移整个项目到CMake构建 #

如果长期维护项目，建议直接切换到CMake构建，更便于依赖管理：

1. 在app/src/main/cpp目录下创建CMakeLists.txt，替换原Android.mk逻辑：

   cmake_minimum_required(VERSION 3.18.1)
   
   project(example)
   
   # 引入capstone和funchook子项目
   add_subdirectory(../../jni/thirdparty/capstone capstone_build)
   add_subdirectory(../../jni/thirdparty/funchook funchook_build)
   
   # 构建主可执行文件
   add_executable(example
       ../../jni/example.cpp
   )
   
   # 链接依赖库
   target_link_libraries(example
       log
       libcxx
       capstone
       funchook
   )
   
   # 设置编译参数
   target_compile_options(example PRIVATE
       -std=c++17
       -fno-exceptions
       -fno-rtti
       -fvisibility=hidden
       -fvisibility-inlines-hidden
   )
   
   set_target_properties(example PROPERTIES
       CXX_STANDARD 17
   )
   

2. 修改build.gradle配置CMake构建：

   android {
       defaultConfig {
           externalNativeBuild {
               cmake {
                   abiFilters 'armeabi-v7a', 'arm64-v8a', 'x86', 'x86_64'
                   arguments "-DANDROID_PLATFORM=android-21", "-DANDROID_STL=none"
               }
           }
       }
       externalNativeBuild {
           cmake {
               path "src/main/cpp/CMakeLists.txt"
           }
       }
   }
   

内容的提问来源于stack exchange，提问作者Alexandru Nitan