NDK调用第三方so文件

说明:此处的so可以是jni生成的或者纯净的C语言的动态库.关于生成.so可参看我的上篇文章.

导入第三方.so.需要新建jniLibs,必须是这个文件名,否则会找不到.so(最简单的方式)
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修改CmakeList文件.
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CmakeList的文件内容

cmake_minimum_required(VERSION 3.4.1)
add_library(
        share-lib#第三方so的名称
        SHARED#动态库标志
        IMPORTED)#导入第三方的标志
#注意这两个属性必须靠在一起,下边是对上边的解释.
set_target_properties(share-lib #第三方so的名称
        PROPERTIES IMPORTED_LOCATION
        ${CMAKE_SOURCE_DIR}/../jniLibs/${ANDROID_ABI}/libshare-lib.so)#设置.so的路径(必须)


add_library( # Sets the name of the library.
        native-lib#jni的loadLibrary的名称
        SHARED#动态库标志
        native-lib.cpp)#jni的源文件
target_include_directories(native-lib PRIVATE
        ${CMAKE_SOURCE_DIR}/../myinclude #配置include的路径(如果需要使用.h文件的话)
        )

find_library( # Sets the name of the path variable.
        log-lib
        log)
target_link_libraries( # 链接所有的.cpp .so,(.h文件不需要)
        native-lib
        share-lib#第三方so的名称
        ${log-lib})

此时,第三方导入完毕调取即可.JNI调用代码如下:native-lib.c

#include <jni.h>
#include <string>

extern "C" std::string getMyString();
using namespace std;
extern "C" JNIEXPORT jstring JNICALL
Java_com_okay_usendkdemo_MainActivity_stringFromJNI(
        JNIEnv *env,
        jobject /* this */) {
    return env->NewStringUTF(getMyString().c_str());
}

调用代码如下:

public class MainActivity extends AppCompatActivity {

    // Used to load the 'native-lib' library on application startup.
    static {
        System.loadLibrary("native-lib");
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Example of a call to a native method
        TextView tv = findViewById(R.id.sample_text);
        tv.setText(stringFromJNI()+"--");
    }

    /**
     * A native method that is implemented by the 'native-lib' native library,
     * which is packaged with this application.
     */
    public native String stringFromJNI();
}