Android NDK应用程序未能加载库

My native library code:

我的本地库代码:

#include <string.h>
#include <jni.h>

jstring Java_com_mindtherobot_samples_ndkfoo_NdkFooActivity_invokeNativeFunction(JNIEnv* env, jobject javaThis) {
  return env->NewStringUTF("Hello from native code!");
}

Android.mk:

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)

LOCAL_MODULE    := libpacman
LOCAL_SRC_FILES := main.cpp
LOCAL_CFLAGS := -DANDROID_NDK
LOCAL_LDLIBS := -llog

include $(BUILD_SHARED_LIBRARY)

MainActivity.java:

public class MainActivity extends Activity {

    static {
        System.loadLibrary("libpacman");
    }

    // declare the native code function - must match main.cpp
    private native String invokeNativeFunction();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // this is where we call the native code
        String hello = invokeNativeFunction();

        new AlertDialog.Builder(this).setMessage(hello).show();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
}

Library is compiled successfully and libpacman.so is in libs/armeabi directory, but logcat says:

成功编译了库和libpacman。libs/armeabi目录也是如此，但logcat说:

E/AndroidRuntime(13060): FATAL EXCEPTION: main
E/AndroidRuntime(13060): java.lang.ExceptionInInitializerError
E/AndroidRuntime(13060):    at java.lang.Class.newInstanceImpl(Native Method)
E/AndroidRuntime(13060):    at java.lang.Class.newInstance(Class.java:1319)
E/AndroidRuntime(13060):    at android.app.Instrumentation.newActivity(Instrumentation.java:1053)
E/AndroidRuntime(13060):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1974)
E/AndroidRuntime(13060):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
E/AndroidRuntime(13060):    at android.app.ActivityThread.access$600(ActivityThread.java:130)
E/AndroidRuntime(13060):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
E/AndroidRuntime(13060):    at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime(13060):    at android.os.Looper.loop(Looper.java:137)
E/AndroidRuntime(13060):    at android.app.ActivityThread.main(ActivityThread.java:4745)
E/AndroidRuntime(13060):    at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime(13060):    at java.lang.reflect.Method.invoke(Method.java:511)
E/AndroidRuntime(13060):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
E/AndroidRuntime(13060):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
E/AndroidRuntime(13060):    at dalvik.system.NativeStart.main(Native Method)
E/AndroidRuntime(13060): Caused by: java.lang.UnsatisfiedLinkError: Couldn't load libpacman: findLibrary returned null
E/AndroidRuntime(13060):    at java.lang.Runtime.loadLibrary(Runtime.java:365)
E/AndroidRuntime(13060):    at java.lang.System.loadLibrary(System.java:535)
E/AndroidRuntime(13060):    at com.example.pacman.MainActivity.<clinit>(MainActivity.java:11)
E/AndroidRuntime(13060):    ... 15 more
W/ActivityManager(  315):   Force finishing activity com.example.pacman/.MainActivity

So, system can not find the library, but if unzip APK file - it's in the lib directory. Why not in the libs?

因此，系统无法找到库，但是如果解压APK文件——它在lib目录中。为什么不在图书馆呢?

Edit. OK, now i fixed the package names:

编辑。好的，现在我修改了包名:

jstring Java_com_wiagames_pacman_MainActivity_invokeNativeFunction(JNIEnv* env, jobject javaThis) {
  return env->NewStringUTF("Hello from native code!");
}

Android.mk and MainActivity.java are the same. Package is com.wiagames.pacman everywhere. But I'm getting error:

Android。可和MainActivity。java是相同的。包是com.wiagames。吃豆子无处不在。但我得到错误:

E/AndroidRuntime(23084): FATAL EXCEPTION: main
E/AndroidRuntime(23084): java.lang.ExceptionInInitializerError
E/AndroidRuntime(23084):    at java.lang.Class.newInstanceImpl(Native Method)
E/AndroidRuntime(23084):    at java.lang.Class.newInstance(Class.java:1319)
E/AndroidRuntime(23084):    at android.app.Instrumentation.newActivity(Instrumentation.java:1053)
E/AndroidRuntime(23084):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1974)
E/AndroidRuntime(23084):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
E/AndroidRuntime(23084):    at android.app.ActivityThread.access$600(ActivityThread.java:130)
E/AndroidRuntime(23084):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
E/AndroidRuntime(23084):    at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime(23084):    at android.os.Looper.loop(Looper.java:137)
E/AndroidRuntime(23084):    at android.app.ActivityThread.main(ActivityThread.java:4745)
E/AndroidRuntime(23084):    at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime(23084):    at java.lang.reflect.Method.invoke(Method.java:511)
E/AndroidRuntime(23084):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
E/AndroidRuntime(23084):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
E/AndroidRuntime(23084):    at dalvik.system.NativeStart.main(Native Method)
E/AndroidRuntime(23084): Caused by: java.lang.UnsatisfiedLinkError: Couldn't load libpacman: findLibrary returned null
E/AndroidRuntime(23084):    at java.lang.Runtime.loadLibrary(Runtime.java:365)
E/AndroidRuntime(23084):    at java.lang.System.loadLibrary(System.java:535)
E/AndroidRuntime(23084):    at com.wiagames.pacman.MainActivity.<clinit>(MainActivity.java:13)
E/AndroidRuntime(23084):    ... 15 more
W/ActivityManager(  315):   Force finishing activity com.wiagames.pacman/.MainActivity

3 个解决方案

#1

According to my experiences in NDK,the path of your class in Android App must be the same as

根据我在NDK的经验，你的类在Android App上的路径必须和

Java_com_mindtherobot_samples_ndkfoo_NdkFooActivity_invokeNativeFunction



Java_com_mindtherobot_samples_ndkfoo [package name]
NdkFooActivity [activity or class name]
invokeNativeFunction [function name]

#2

Your classname is visibly not NdkFooActivity. Also make sure that your java package is com.mindtherobot.samples.ndkfoo. The name of native function and the Java context from which are you calling it must be in sync. Normally you would produce the native header with javah -jni which works on the already compiled class, not the java sources.

你的类名显然不是NdkFooActivity。还要确保java包是com.mindtherobo .sampl .ndkfoo。本机函数的名称和调用它的Java上下文必须是同步的。通常，您将使用java -jni生成本机头文件，它在已编译的类上工作，而不是在java源代码上。

#3

The library name you pass to System.loadLibrary() should simply be pacman, not libpacman.

传递给System.loadLibrary()的库名应该是pacman，而不是libpacman。

#1