Question

不熟悉c ++，有人可以帮助我将cmd添加到myStr数组并将其传递给main()函数，这是我目前所拥有的：

JNIEXPORT void JNICALL Java_my_package_JNIActivity_callCmdLine(
    JNIEnv *env, jobject obj, jstring cmd)
{
    const char *nativeString = env->GetStringUTFChars(cmd, 0);
    env->ReleaseStringUTFChars(cmd, nativeString);

    char * myStr [] = {"v", nativeString};

    //int main(int argc, char *argv[])
    main(1, myStr); 
}

Answer 1

好吧，在你完成它之前不要释放它。

char * nativeString;

{    const char * _nativeString = env->GetStringUTFChars(cmd, 0);
     nativeString = strdup (_nativeString);
     env->ReleaseStringUTFChars(cmd, _nativeString);
}

char * myStr [] = {"v", nativeString};
main(1, myStr); 

free (nativeString);

Answer 2

为什么不利用对象来保证删除是自动完成的？？

class ConvertStringHelper
{
public:
    ConvertStringHelper( JNIEnv *env, jstring value )
    {
        m_str = env->GetStringUTFChars(value, 0);
        m_value = &value;
        m_env = env;
    }
    ~ConvertStringHelper()
    {
        m_env->ReleaseStringUTFChars( *m_value, m_str);
    }

    jstring* m_value;
    const char *m_str;
    JNIEnv *m_env;
};

然后：

    ConvertStringHelper helper( env, cmd );
    const char* nativeStr = helper.m_str;
    // nativeStr is valid in helper's scope and memory will be cleanly released when exiting the scope!

jni将字符串转换为char数组

2 个答案: