使用JNI只有一个C共享库和头文件从Android的调用C [英] Call C from Android using JNI with only a C shared library and header file
问题描述
Android Studio 0.3.1
您好,
我已经写在C以下的库,但没有源$ C $ C它只有libapp_module.so
I have the following library written in C but don't have the source code for it only the libapp_module.so
libapp_module.so: ELF 32-bit LSB shared object, ARM, version 1 (SYSV), dynamically linked (uses shared libs), not stripped
我对这个库中的头文件:
I have the header file for this library:
#ifdef __cplusplus
extern "C" {
#endif
#ifdef _WIN32
#define LIB_API(type) __declspec(dllexport) type
#else
#define LIB_API(type) type
#endif
LIB_API(int) module_init();
#ifdef __cplusplus
}
#endif
问题是例外,当我尝试从我的Android应用程序调用该函数:
The problem is the exception when I try and call the function from my Android App:
D/dalvikvm﹕ Added shared lib /data/app-lib/com.sunsystems.snaptest-1/libapp_module.so 0x416f3d88
D/dalvikvm﹕ No JNI_OnLoad found in /data/app-lib/com.sunsystems.snaptest-1/libapp_module.so 0x416f3d88, skipping init
W/dalvikvm﹕ No implementation found for native Lcom/sunsystems/snaptest/App_Module;.module_init:()I
UnsatisfiedLinkError: Native method not found: com.sunsystems.snaptest.App_Module.module_init:()I
这是我在做什么。
我创建了一个Android应用程序,我想,所以我创建了一个名为App_Module.java类从我的应用程序调用宏module_init()
I have created a Android App and I want to call that module_init() from my App so I have created a class called App_Module.java
public class App_Module {
/* Load native C libraries */
static {
System.loadLibrary("app_module");
}
public native static int module_init();
}
和我使用JNI这样在我的项目的根目录:
And I used JNI like this in my root of the project:
javah -jni -classpath build/classes/debug -d jni/ com.sunsystems.snaptest.App_Module
即生成下面的头接口:
Which generated the following header interface:
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_sunsystems_snaptest_App_Module */
#ifndef _Included_com_sunsystems_snaptest_App_Module
#define _Included_com_sunsystems_snaptest_App_Module
#ifdef __cplusplus
extern "C" {
#endif
/*
* Class: com_sunsystems_snaptest_App_Module
* Method: module_init
* Signature: ()I
*/
JNIEXPORT jint JNICALL Java_com_sunsystems_snaptest_App_Module_module_1init
(JNIEnv *, jclass);
#ifdef __cplusplus
}
#endif
#endif
然后在我的Android应用我加载库在上面App_Module类并调用它像这样:
Then in my Android App I load the library in the above App_Module class and call it like this:
App_Module.module_init()
所以我想它找不到libapp_module.so库中的符号。
So I guess it cannot find symbol inside the libapp_module.so library.
非常感谢您的任何建议,
Many thanks for any suggestions,
推荐答案
您必须实现本地方法,使其调用函数库中的。例如:
You have to implement the native method and make it call the function in your library. For example:
#include "header_file_for_your_library.h"
#include "com_sunsystems_snaptest_App_Module.h"
JNIEXPORT jint JNICALL Java_com_sunsystems_snaptest_App_Module_module_1init(JNIEnv *env, jclass klass) {
return module_init();
}
就有关JNI或Android NDK任何教程将有进一步的细节。
Just about any tutorial on JNI or Android NDK will have further details.
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