LOCAL_PATH:= $(call my-dir)

include $(CLEAR_VARS)

LOCAL_SRC_FILES := $(call all-java-files-under, src)

# apk name
LOCAL_PACKAGE_NAME := CallHelper

LOCAL_CERTIFICATE := platform
include $(BUILD_PACKAGE)
LOCAL_JNI_SHARED_LIBRARIES := libphone-number-jni

# so can call jni/Android.mk
include $(call all-makefiles-under,$(LOCAL_PATH))

主要是最后一条，如果你在Linux 的终端执行 mmm packages/apps/CallHelper 时除了会生成CallHelper.apk外还会去编译jni/Android.mk 在类似out\target\product\sp8825ea\system\lib生成libphone-number-jni.so 文件。

再看下jni/Android.mk

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE_TAGS := optional

# the .so file name, remember need lib in the front
LOCAL_MODULE    := libphone-number-jni

# the main cpp file name
LOCAL_SRC_FILES := number-jni.cpp 


LOCAL_PRELINK_MODULE := false
include $(BUILD_SHARED_LIBRARY)

再看下jni/number-jni.cpp

#include <jni.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include "NumberInfo.h"

//注意下这个方法名，里面有包名信息，如果要在你自己项目中使用这个号码归属地查询，包名不同的话记得要修改这里
extern "C" {
   JNIEXPORT jbyteArray JNICALL Java_com_waitingfy_callhelper_NativeFunction_getLocationFromJni(JNIEnv* env,jclass tis,jstring filename,jstring number);
};

//注意下这个方法名，里面有包名信息，如果要在你自己项目中使用这个号码归属地查询，包名不同的话记得要修改这里
JNIEXPORT jbyteArray JNICALL Java_com_waitingfy_callhelper_NativeFunction_getLocationFromJni(JNIEnv* env,jclass tis,jstring filename,jstring number)
{

    jboolean iscopy;
    const char* fnData=(env)->GetStringUTFChars( filename, &iscopy);//get binary file name
    const char* num = (env)->GetStringUTFChars(number, &iscopy); //get number
     int phoneNum = 0;   
     sscanf(num,"%7d",&phoneNum);
   NumberInfoAction action;
    char* location = action.GetCityNameByNumber(fnData,phoneNum);// get result
    jbyte *by = (jbyte*)location;
    jbyteArray jarray = env->NewByteArray(strlen(location));// change to jbytearray
    env->SetByteArrayRegion(jarray,0,strlen(location),by);
    return jarray;
}

jni/NumberInfo.h 就不列出来了。去掉了把txt转换成二进制文件的方法就留了查询方法。

最后看下src/com.waitingfy.callhelper/NativeFunction.java

package com.waitingfy.callhelper;



public class NativeFunction  {
    //方法前有native 关键词,这里的getLocationFromJni跟jni/number-jni.cpp中的遥相呼应
    public static native byte[]  getLocationFromJni(String filename,String number);
    /** Load jni .so on initialization */
    static {
         System.loadLibrary("phone-number-jni");//注:不需要lib开头和.so结束,只需要中间的名字  
    }

}