Java Android NDK：在...跳过初始化中找不到JNI_OnLoad：但是有JNI_OnLoad
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Android NDK : No JNI_OnLoad found in ... skipping init : But there is JNI_OnLoad
提问by venky
I am asking this question again because I have to.
我再次问这个问题，因为我必须这样做。
I am having this error while running a NDK based application.
运行基于 NDK 的应用程序时出现此错误。
D dalvikvm: No JNI_OnLoad found in /data/app-lib/com.venky-1/libme.so 0xa5082228, skipping init W dalvikvm: No implementation found for native Lcom/venky/Home;.getPermission:(Landroid/app/Activity;)I
D dalvikvm：在 /data/app-lib/com.venky-1/libme.so 0xa5082228 中找不到 JNI_OnLoad，跳过初始化 W dalvikvm：未找到本机 Lcom/venky/Home 的实现；.getPermission:(Landroid/app/Activity ;）一世
I have been through
我经历过
- No JNI_OnLoad found in ... skipping init
- No JNI_OnLoad found skipping init > Application shutdown
- No JNI_Onload() found and VM shutting down
- JNI_OnLoad not found
- 在 ... 跳过 init 中找不到 JNI_OnLoad
- 没有发现 JNI_OnLoad 跳过 init > 应用程序关闭
- 找不到 JNI_Onload() 并且 VM 正在关闭
- 未找到 JNI_OnLoad
Their problem was either
他们的问题要么是
- They were not using JNI_OnLoad because they used JNI specific naming convention (For example Java_com_venky_Home_start()). Hence this message has no significance as there is an alternative.
- They were using C++ and there was function name mangling.
- 他们没有使用 JNI_OnLoad，因为他们使用了 JNI 特定的命名约定（例如 Java_com_venky_Home_start()）。因此，该消息没有意义，因为存在替代方案。
- 他们使用的是 C++，并且有函数名修改。
My case is entirely different. And the above two are invalid in my case. I am using C files. So no mangling. And I am not using JNI kind of function names. I am manually registering the functions using JNI_OnLoad. Hence my conclusion is that "No Implementation Found" is due to the fact that the application is somehow unable to find JNI_OnLoad. But why? It is present in the C file.
我的情况完全不同。以上两个在我的情况下是无效的。我正在使用 C 文件。所以没有损坏。而且我没有使用 JNI 类型的函数名称。我正在使用 JNI_OnLoad 手动注册这些函数。因此，我的结论是“未找到实现”是由于应用程序以某种方式无法找到 JNI_OnLoad。但为什么？它存在于 C 文件中。
Relevant sections of code are as follows. Please ask if you need more.
相关代码段如下。请询问您是否需要更多。
jni/Android.mk
jni/Android.mk
include $(CLEAR_VARS)
LOCAL_MODULE := me
LOCAL_SRC_FILE := me.c
include $(BUILD_SHARED_LIBRARY)
com/venky/Home.java
com/venky/Home.java
package com.venky;
import android.app.Activity;
import android.os.Bundle;
public class Home extends Activity {
static {
System.loadLibrary("me");
}
private native int getPermission(Activity activity);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.home);
getPermission(this);
}
}
jni/me.c
jni/me.c
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <android/log.h>
#include <jni.h>
#define LOG_TAG "com.venky.me"
#define LOG_D(...) __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, __VA_ARGS__)
#define LOG_F(fn_name) __android_log_write(ANDROID_LOG_DEBUG, LOG_TAG, "Called : " fn_name )
static JavaVM *java_vm;
jint JNI_OnLoad(JavaVM *vm, void *reserved)
{
LOG_F ("JNI_OnLoad");
java_vm = vm;
// Get JNI Env for all function calls
JNIEnv* env;
if ((*vm)->GetEnv(vm, (void **) &env, JNI_VERSION_1_6) != JNI_OK) {
LOG_D ("GetEnv failed.");
return -1;
}
// Find the class calling native function
jclass NativeUsb = (*env)->FindClass(env, "com/venky/Home");
if (class_home == NULL) {
LOG_D ("FindClass failed : No class found.");
return -1;
}
// Register native method for getUsbPermission
JNINativeMethod nm[1] = {
{ "getPermission", "(Landroid/app/Activity;)I", get_permission}
};
if ((*env)->RegisterNatives(env, NativeUsb, nm , 1)) {
LOG_D ("RegisterNatives Failed.");
return -1;
}
return JNI_VERSION_1_6;
}
int get_permission (jobject activity)
{
LOG_F ("get_usb_permission");
}
采纳答案by venky
By help of @AlexCohn, I found out my error. And what a silly stupid error it was.
在@AlexCohn 的帮助下，我发现了我的错误。这是多么愚蠢的错误啊。
jni/Android.mk
jni/Android.mk
include $(CLEAR_VARS)
LOCAL_MODULE := me
- LOCAL_SRC_FILE := me.c
+ LOCAL_SRC_FILES := me.c
include $(BUILD_SHARED_LIBRARY)
Because of this, me.c wasn't compiling. Hence it was not included in the built shared library. I had wasted a couple of hours on this at least.
因此，me.c 没有编译。因此它没有包含在构建的共享库中。我至少在这上面浪费了几个小时。
