JNI是什么的char []（字符数组）的方法描述符？ [英] JNI What is the method descriptor for char [] (char array)?

问题描述

我的Java类code片段。我想使用JNI从我的C文件访问getReg_chal（）方法：

My JAVA class code snippet .I want to access getReg_chal() method from my C file using JNI:

public char[] getReg_chal() {
        return reg_chal;
    }

我的C文件做一些JNI操作：

My C file doing some jni operation:

mid = (*env)->GetMethodID(env, info, "getReg_chal()", "()I");

mid = (*env)->GetMethodID(env, info, "getReg_chal()", ***);

我想知道我的char []方法描述符。写作（）I给了我假的方法描述错误，因为（）我被用于诠释。我将填补什么的 * 的。
请帮帮我。先谢谢了。

I want to know the method descriptor for my char[]. Writing "()I" gives me bogus method descriptor error since ()I is used for Int. What would i fill in *. Please Help me. Thanks in advance.

推荐答案

该方法的签名是（）[C 。

您可以阅读有关的细节这里和这里。

You can read about the details here and here.

要调用的使用方法ID的方法，你只是喜欢写东西。

To call the method using the method id, you'd just write something like

jobject obj = ... // This is the object you want to call the method on
jcharArray arr = (jcharArray) (*env)->CallObjectMethod(env, obj, mid);
int count = (*env)->GetArrayLength(env, arr);
jchar* chars = (*env)->GetCharArrayElements(env, arr, 0);
// Here, "chars" is a C pointer to an array of "count" characters. It's NOT
// going to be 0-terminated, so be careful! Here's where you would do your
// logging or whatever. One possible way to do this is by turning the `jchar`
// array into a proper 0-terminated character string:
char * message = malloc(count + 1);
memcpy(message, chars, count);
message[count] = 0;
LOGD("NDK:LC: [%s]", message);

// When you're done you must call this!
(*env)->ReleaseCharArrayElements(env, arr, chars, 0);

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