JNI方法:正式参数列表的长度不同 [英] JNI method: formal argument lists differ in length

问题描述

我正在尝试修改一个JNI函数，该函数从Java层获取一个字符串参数.

I'm trying to emend a JNI function that takes a string argument from the java layer.

最初，.java文件中的Java代码是:

Initially, the java code from the .java file was:

callJNIMethod();

我正在尝试更改它，以便可以给它一个字符串，如下所示:

I'm trying to change it so that I can give it a string, like this:

String arg = "abcd";
callJNIMethod(arg);

在我的JNI代码中，这是以前的功能:

In my JNI code, this is what the function previously looked like:

JNIEXPORT jboolean JNICALL Java_com_file_app_Activity_callJNIMethod(
JNIEnv *env, jclass clazz){

//use the string
}

这就是我将其更改为的内容(在包装器.cpp文件和标头.h文件中):

This is what I changed it to (in the wrapper .cpp file and the header .h file):

JNIEXPORT jboolean JNICALL Java_com_file_app_Activity_callJNIMethod(
JNIEnv *env, jclass clazz, jstring str);

我收到一个错误消息，称方法callJNIMethod无法应用于给定类型.

I'm getting an error that the method callJNIMethod cannot be applied to the given types.

required: no arguments
found: java.lang.String
reason: actual and formal argument lists differ in length
Note: Some input files use or override a deprecated API.

有什么想法吗?

推荐答案

您通过编辑.h文件而误入歧途.对本机方法的更改应从您的Java源代码开始.

You went astray by editing the .h file. Changes to native methods should begin in your Java source.

.h文件应由javah从编译的.class文件中生成.您可以将构建系统设置为在每个构建中重新运行javah.这样，您将立即看到本机方法实现是否不再与Java源代码中的本机声明匹配.

The .h file should be generated by javah from the compiled .class file. You can set up your build system to re-run javah with each build. That way you'll see right away if the native method implementations no longer match the native declarations in your Java source.

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