Android NDK项目：java.lang.UnsatisfiedLinkError：dalvik.system.PathClassLoader

如何解决Android NDK项目：java.lang.UnsatisfiedLinkError：dalvik.system.PathClassLoader

我是NDK的新手。

我想在我的标准Java Android Studio项目中添加一些C ++代码。

我做了什么：

1. 在主文件夹下添加cpp文件夹

2. 在my cpp文件夹中添加myccplib.cpp和myccplib.h

3. 在Gradle（模块）中添加以下内容：

   android { 
   
    externalNativeBuild {
   
            cmake {
   
                version "3.10.2"
            } 
    } 
    }
   

myccplib.cpp中的

4. 代码：

   #include "myccplib.h"
   
   
    #include <jni.h>
    #include <string>
   
    extern "C" JNIEXPORT jstring JNICALL
   
   
    Java_com_example_tof_MainActivity_stringFromJNI( JNIEnv *env,jobject /* this */) {
        std::string hello = "Hello,World!";
        return env->NewStringUTF(hello.c_str());
    }
   

5. MainActivity.java中的代码：

 public class MainActivity extends AppCompatActivity {

    static {
        System.loadLibrary("myccplib"); // "myjni.dll" in Windows,"libmyjni.so" in Unixes
    }


    public native String stringFromJNI();


 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

  String s = stringFromJNI();
        Log.d("stringFromJNI " + s);



}

}

我的CMakeLists.txt文件：

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.

add_library( # Sets the name of the library.
             native-lib

             # Sets the library as a shared library.
             SHARED

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

                       # Links the target library to the log library
                       # included in the NDK.
                       ${log-lib} )

问题：我崩溃了：

2020-10-14 19:02:45.465 25918-25918/com.example.tof E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.tof,PID: 25918
java.lang.UnsatisfiedLinkError: dalvik.system.PathClassLoader[DexPathList[[zip file "/data/app/com.example.tof-t8Csh416BSdO6UBfZv0mOw==/base.apk"],nativeLibraryDirectories=[/data/app/com.example.tof-t8Csh416BSdO6UBfZv0mOw==/lib/arm64,/system/lib64,/product/lib64]]] couldn't find "libmyccplib.so"
    at java.lang.Runtime.loadLibrary0(Runtime.java:1067)
    at java.lang.Runtime.loadLibrary0(Runtime.java:1007)
    at java.lang.System.loadLibrary(System.java:1667)
    at com.example.tof.MainActivity.<clinit>(MainActivity.java:37)

我使用的是Android 4.0。

有人能告诉我我想念什么吗？

谢谢！