尝试访问 nativeLibraryDir 时出错

Question

我正在尝试在 jni 中访问 getPackageManager.getApplicationInfo。

const char* getNativeLibPath(JNIEnv* env, jobject thiz, const char* libraryName, const char* packageName) {
    jclass contextClass = env->GetObjectClass(thiz);
    jmethodID getPackageManager = env->GetMethodID(contextClass, "getPackageManager", "()Landroid/content/pm/PackageManager;");
    jobject instantiatePackageManager = env->CallObjectMethod(thiz, getPackageManager);
    jclass packageManagerClass = env->GetObjectClass(instantiatePackageManager);
    jmethodID getApplicationInfo = env->GetMethodID(packageManagerClass, "getApplicationInfo", "(Ljava/lang/String;I)Landroid/content/pm/ApplicationInfo;");
    jobject instantiateApplicationInfo = env->CallObjectMethod(thiz, getApplicationInfo, packageName, 0);
    jclass applicationInfoClass = env->GetObjectClass(instantiateApplicationInfo);
    jfieldID nativeLibraryDir = env->GetFieldID(applicationInfoClass, "nativeLibraryDir", "Ljava/lang/String;");
    auto string = (jstring) env->GetObjectField(instantiateApplicationInfo, nativeLibraryDir);
    const char* returnValue = env->GetStringUTFChars(string, nullptr);
    std::string appendedResult = std::string(returnValue) + std::string("/") + std::string(libraryName);
    return appendedResult.c_str();
}

这是我的代码。但是由于某种原因我收到了这个错误：JNI ERROR (app bug): accessed stale WeakGlobal 0x74eecd21ff (index 1324143135 in a table of size 38) JNI DETECTED ERROR IN APPLICATION: use of deleted weak global reference 0x74eecd21ff 感谢您的帮助！

Answer 1

您的代码至少存在三个问题：

您使用 const char * 调用 getApplicationInfo，它需要一个 Java 字符串：

jobject instantiateApplicationInfo = env->CallObjectMethod(instantiatePackageManager, getApplicationInfo, env->NewStringUTF(packageName), 0);

需要调用env->ReleaseStringUTF(returnValue)释放Java侧的字符串
你不能 return 那样 const char *。要么直接 return std::string，要么使用 new char[] 分配内存并让调用者释放它。

尝试访问 nativeLibraryDir 时出错

Error when trying to access nativeLibraryDir

android

c++

java-native-interface