1、创建cpp目录,用于存放C和C++代码。
2、创建CMake构建脚本CMakeLists.txt文件,将其放在cpp目录中。
# Sets the minimum version of CMake required to build the native library.
cmake_minimum_required(VERSION 3.22.1)
# Declares and names the project.
project("test-project")
# 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.
test
# Sets the library as a shared library.
SHARED
# Provides a relative path to your source file(s).
test.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.
test
# Links the target library to the log library
# included in the NDK.
${log-lib})
3、配置CMakeLists.txt文件路径和CMake的版本,使CMake工具能够编译该文件。在app中的build.gradle加入以下代码。
4、创建test.cpp用于测试。
#include <jni.h>
#include <android/log.h>
extern "C"
JNIEXPORT void JNICALL
Java_com_example_cmakelisttest_MainActivity_testMethod(JNIEnv *env, jobject) {
__android_log_print(ANDROID_LOG_INFO,"TAG","Hello Native!");
}
5、加载C或C++代码生成的so库,并调用其中的方法。
public class MainActivity extends AppCompatActivity {
static {
System.loadLibrary("test"); // 加载生成的so库
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
testMethod(); // 调用native方法
}
public native void testMethod(); // 定义native方法
}
6、运行该程序,如果成功,则会打印"Hello Native!"。
附录:文件结构图