2021-04-12 学习android jni开发。。

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

cmake_minimum_required(VERSION 3.4.1)

# 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.

//   第一步就是加入直接的编写的c++文件。。。

add_library(# Sets the name of the library.

            mp3-lite

            # Sets the library as a shared library.

            SHARED

            # Provides a relative path to your source file(s).

            src/main/cpp/audio_lame.c

        )

//加入要引用的c++库。。。

add_library(mp3lame

SHARED

            IMPORTED )

//设置要加入的动态链接库的地址。。。。

set_target_properties(mp3lame

PROPERTIES IMPORTED_LOCATION

            ../../../../libs/${CMAKE_ANDROID_ARCH_ABI}/libmp3lame.so )

//设置CMAKE_CXX_FLAGS 

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11")

//这是在引入头文件。。

include_directories(src/main/cpp)

//找到ndk自带的动态链接库。。

find_library(# Sets the name of the path variable.

              log-lib

              log )

//把所有的库链接到我们写的第一个库上。。。。完成。。。。

target_link_libraries(# Specifies the target library.

                      mp3-lite

                    mp3lame

                      # Links the target library to the log library

                     # included in the NDK.

                      ${log-lib} )