CMake : 遞歸的添加所有cpp文件

最近在使用android studio的時候又發現了一個非常不方便的地方：

每次創建新的C++文件，都需要手動把新創建的C++文件名添加到CMakeLists.txt文件中，不然的話編輯器的頂部就會一直報：

目前我的項目結構如下：

 對應的CMakeLists.txt文件如下：

# For more information about using CMake with Android Studio, read the
# documentation: https://d.android.com/studio/projects/add-native-code.html

# Sets the minimum version of CMake required to build the native library.

cmake_minimum_required(VERSION 3.4.1)

# Add header file path
# include_directories(src/main/cpp/include)

# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds them for you.
# Gradle automatically packages shared libraries with your APK.

add_library( # Sets the name of the library.
        HaAlgorithm

        # Sets the library as a shared library.
        SHARED

        src/main/cpp/HaAptUserTuneJNI.cpp
        src/main/cpp/AndroidLog.cpp

        # Algorithm
        src/main/cpp/HaAlgorithm/apt_tune.cpp
        src/main/cpp/HaAlgorithm/invfreqz.cpp
        src/main/cpp/HaAlgorithm/main.cpp
        src/main/cpp/HaAlgorithm/sort_sos.cpp
        src/main/cpp/HaAlgorithm/tf2sos.cpp
        src/main/cpp/HaAlgorithm/user_tune_eq.cpp
        src/main/cpp/HaAlgorithm/wdrc_payload.cpp

        # CommandDefine
        src/main/cpp/HaCommandDefine/NoiseReductionPayload.cpp
        )

# Searches for a specified prebuilt library and stores the path as a
# variable. Because CMake includes system libraries in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.

find_library( # Sets the name of the path variable.
        log-lib

        # Specifies the name of the NDK library that
        # you want CMake to locate.
        log)

# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in this
# build script, prebuilt third-party libraries, or system libraries.

target_link_libraries( # Specifies the target library.
        HaAlgorithm
        android
        # Links the target library to the log library
        # included in the NDK.
        ${log-lib})

可以看到，add_library 一行中已經添加了很多的cpp 文件， 有些還在第二級的子目錄。

解決辦法：

可以通過file指令搜索出所有后綴名為".cpp"的文件，然后添加到項目中，新的CMakeLists.txt修改如下：

cmake_minimum_required(VERSION 3.4.1)

set(CMAKE_CXX_STANDARD 11)

file(GLOB_RECURSE native_srcs src/main/cpp/*.cpp)

add_library(HaAlgorithm SHARED ${native_srcs})

target_link_libraries(
        HaAlgorithm
        android
        log
)

重點在於標紅的那一句，什么意思呢，相當於告訴CMake, 搜索當前目錄以及子目錄中所有的以.cpp結尾的文件，然后把它們保存到  native_srcs 變量中。這里要注意CMakeLists.txt文件的位置，我是放在項目根目錄下，所以我在搜索的時候指定了前綴：src/main/cpp。

這樣修改之后，以后再添加新的C++代碼就不需要再修改CMake文件了，編譯APK的時候CMake會自動找出符合條件的C++文件並且參與到構建當中。

美中不足的是，雖然編譯最終apk的時候,新添加的文件也會被編譯，但是新添加的C++文件上方還是會出現：

 並且點擊右邊的“Sync Now” 之后還是沒用！

經過反復嘗試發現可以通過點擊菜單欄上的“Refresh Linked  C++ Projects” 讓它消失。