本文的思路：
android APP调用自定义java API,自定义java API调用自定义jni接口
1：在android源码目录framework/base下面创建add目录
add目录里面的结构如下：
里面的Nadd.java android_jnitest_Nadd.cpp 和Android.mk内容如下：
Nadd.java
package android.jnitest;
public class Nadd {
static {
System.loadLibrary("hello_jni");
}
public native int nadd(int a, int b);
}
android_jnitest_Nadd.cpp
#define LOG_TAG "hello-JNI"
#include
#include
#include
#include
#include
#include
#include
#include "jni.h"
#include "JNIHelp.h"
#include "android_runtime/AndroidRuntime.h"
static jint native_nadd(JNIEnv *env, jobject obj, jint a, jint b)
{
return (a + b);
}
static JNINativeMethod gMethods[] = {
{"nadd", "(II)I", (void *)native_nadd},
};
static int register_android_jnitest_Nadd(JNIEnv *env)
{
return android::AndroidRuntime::registerNativeMethods(env, "android/jnitest/Nadd", gMethods, NELEM(gMethods));
}
jint JNI_OnLoad(JavaVM *vm, void *reserved)
{
JNIEnv *env = NULL;
if (vm->GetEnv((void **)&env, JNI_VERSION_1_4) != JNI_OK) {
printf("Error GetEnv\n");
return -1;
}
assert(env != NULL);
if (register_android_jnitest_Nadd(env)
printf("register_android_test_hello error.\n");
return -1;
}
return JNI_VERSION_1_4;
}
Android.mk
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_PRELINK_MODULE := false
LOCAL_SRC_FILES := \
android_jnitest_Nadd.cpp
LOCAL_SHARED_LIBRARIES := \
libandroid_runtime
LOCAL_MODULE := libhello_jni
include $(BUILD_SHARED_LIBRARY)
上面的步骤已经将代码准备好了
2:修改build/core/pathmap.mk文件
在FRAMEWORKS_BASE_SUBDIRS变量后添加add\，代码如下
FRAMEWORKS_BASE_SUBDIRS := \
$(addsuffix /java, \
core \
graphics \
location \
media \
opengl \
sax \
telephony \
wifi \
vpn \
keystore \
add \
)
3:修改frameworks/base/Android.mk 文件
在packages_to_document变量后添加自己源代码的包名称，如android/jnitest，结果如下
packages_to_document := \
android \
javax/microedition/khronos\
android/jnitest
4:make update-api
这一步更新api,api文档在frameworks/base/api/current.txt
5:修改build/target/product/base.mk
在PRODUCT_PACKAGES += \后面添加 libhello_jni
PRODUCT_PACKAGES += \
20-dns.conf \
95-configured \
am \
android.policy \
android.test.runner \
app_process \
applypatch \
bmgr \
bugreport \
content \
dhcpcd \
dhcpcd-run-hooks \
dnsmasq \
framework \
fsck_msdos \
ime \
javax.obex \
libSR_AudioIn \
libandroid \
libandroid_runtime \
libandroid_servers \
libaudioeffect_jni \
libaudioflinger \
libbundlewrapper \
libcamera_client \
libcameraservice \
libchromium_net \
libdl \
libdrm1 \
libdrm1_jni \
libeffects \
libiprouteutil \
libjni_latinime \
libjnigraphics \
libmedia \
libmedia_jni \
libmediaplayerservice \
libmtp \
libnetlink \
libnetutils \
libreference-ril \
libreverbwrapper \
libril \
librtp_jni \
libsensorservice \
libskia \
libsonivox \
libsoundpool \
libsqlite \
libstagefright \
libstagefright_amrnb_common \
libstagefright_avc_common \
libstagefright_enc_common \
libstagefright_foundation \
libstagefright_omx \
libstagefright_yuv \
libsystem_server \
libusbhost \
libutils \
libvisualizer \
libvorbisidec \
libwpa_client \
media \
media_cmd \
mediaserver \
monkey \
mtpd \
ndc \
netcfg \
netd \
ping \
platform.xml \
pppd \
pm \
racoon \
run-as \
schedtest \
screenshot \
sdcard \
services \
settings \
svc \
system_server \
tc \
vdc \
vold \
webview \
wm\
libhello_jni
6:make PRODUCT-sdk-sdk -j 4
7:编译好后，自己的sdk会编译到out/host/linux-x86/下，里面的android-sdk_eng.xxx_linux-x86就是自己的sdk，在eclipse中选择自己sdk的路径
如下图：我这里只是介绍，没有选择，用户可以选择~/out/host/linux-x86/android-sdk_eng.xxx_linux-x86路径,然后点击Apply
8:编写app测试
eclipse创建一个最简单的hello工程，
将里面的MainActivity.java内容替换如下(或者来这里下载http://download.csdn.net/detail/a624731186/7219509)
package com.example.jnitest;
import android.jnitest.Nadd;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Nadd test = new Nadd();
setTitle("The Native Add Result is "+String.valueOf(test.nadd(30, 30)));
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
)
)
