原文地址：http://blog.csdn.net/goleftgoright/article/details/7406292?reload
关于Android应用与Framework的socket通信，相信关心这个问题的朋友们已经看过《android使用socket使底层和framework通信》这篇文章，美中不足的是作者只贴出一些关键的代码片段而并没有放出源码。我这里还是以一个能实际运行的例子为基础来讲，这样也方便大家学习。
首先看一下效果，如下图。我填写姓名"Potter"，选择性别"Mr"然后点击发送，底层socket收到消息后将消息直接返回给我，我将返回的结果（Mr.Potter）直接显示在Result。
ok，有了初步了解后我们现在来看一下如何一步步实现这个例子。
1、配置system/core/rootdir/init.rc。我在init.rc加入如下配置
service htfskservice /system/bin/htfsk
class main
socket htfsk stream 666 system system
oneshot
这里配置了一个名为 “htfskservice” 的服务，手机开机后该服务会自启动并运行/system/bin目录下的脚本htfsk（步骤二将提到如何生成这个脚本）。
同时这里还配置了一个名为 "htfsk" 的socket，并且只有拥有system权限的应用才允许连接这个socket，如何使应用获取system权限可以参考http://my.unix-center.net/~Simon_fu/?p=531这篇文章。
666表示socket的权限
2、编写socket服务端代码，生成可执行脚本htfsk。
首先来看下socket服务端代码 htfsk.c ，内容如下：
#define SOCKET_NAME "htfsk"
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/un.h>
#include <cutils/sockets.h>
#include <utils/Log.h>
#include <android/log.h>
int main(){
char log[200];
int connect_number = 6;
int fdListen = -1, new_fd = -1;
int ret;
struct sockaddr_un peeraddr;
socklen_t socklen = sizeof (peeraddr);
int numbytes ;
char buff[256];
//这一步很关键，就是获取init.rc中配置的名为 "htfsk" 的socket
fdListen = android_get_control_socket(SOCKET_NAME);
if (fdListen < 0) {
sprintf(log,"Failed to get socket '" SOCKET_NAME "' errno:%d", errno);
__android_log_write(ANDROID_LOG_DEBUG,"FTM_JNI",log);
exit(-1);
}
//开始监听
ret = listen(fdListen, connect_number);
sprintf(log,"Listen result %d",ret);
__android_log_write(ANDROID_LOG_DEBUG,"FTM_JNI",log);
if (ret < 0) {
perror("listen");
exit(-1);
}
//等待Socket客户端发启连接请求
new_fd = accept(fdListen, (struct sockaddr *) &peeraddr, &socklen);
sprintf(log,"Accept_fd %d",new_fd);
__android_log_write(ANDROID_LOG_DEBUG,"FTM_JNI",log);
if (new_fd < 0 ) {
sprintf(log,"%d",errno);
__android_log_write(ANDROID_LOG_DEBUG,"FTM_JNI",log);
perror("accept error");
exit(-1);
}
while(1){
//循环等待Socket客户端发来消息
__android_log_write(ANDROID_LOG_DEBUG,"FTM_JNI","Waiting for receive");
if((numbytes = recv(new_fd,buff,sizeof(buff),0))==-1){
sprintf(log,"%d",errno);
__android_log_write(ANDROID_LOG_DEBUG,"FTM_JNI",log);
perror("recv");
continue;
}
//发送消息回执给Socket客户端
if(send(new_fd,buff,strlen(buff),0)==-1)
{
perror("send");
close(new_fd);
exit(0);
}
}
close(new_fd);
close(fdListen);
return 0;
}
写好服务端代码后我们要将他编译成可执行脚本htfsk，编译的Android.mk内容如下：
LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE_TAGS :=optional
LOCAL_C_INCLUDES := $(KERNEL_HEADERS)
LOCAL_SHARED_LIBRARIES := libcutils liblog
LOCAL_MODULE:= htfsk
LOCAL_SRC_FILES:=htfsk.c
LOCAL_PRELINK_MODULE := false
include $(BUILD_EXECUTABLE)
编译成功后就会在/system/bin/目录下找到生成的可执行脚本htfsk
3、编写客户端java代码。核心代码如下：
SocketClient.java
public class SocketClient {
private final String SOCKET_NAME = "htfsk";
private LocalSocket client;
private LocalSocketAddress address;
private boolean isConnected = false;
private int connetTime = 1;
public SocketClient() {
client = new LocalSocket();
address = new LocalSocketAddress(SOCKET_NAME, LocalSocketAddress.Namespace.RESERVED);
new ConnectSocketThread().start();
}
public String sendMsg(String msg) {
if (!isConnected) {
return "Connect fail";
}
try {
BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
PrintWriter out = new PrintWriter(client.getOutputStream());
out.println(msg);
out.flush();
return in.readLine();
} catch (IOException e) {
e.printStackTrace();
}
return "Nothing return";
}
private class ConnectSocketThread extends Thread {
@Override
public void run() {
while (!isConnected && connetTime <= 10) {
try {
sleep(1000);
Log.i("SocketClient","Try to connect socket;ConnectTime:"+connetTime);
client.connect(address);
isConnected = true;
} catch (Exception e) {
connetTime++;
isConnected = false;
Log.i("SocketClient","Connect fail");
}
}
}
}
public void closeSocket() {
try {
client.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
MySocketActivity.java
public class MySocketActivity extends Activity {
private SocketClient socketClient = null;
private static String INFO;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Log.i("MySocketActivity", "Sleep waiting for service socket start");
socketClient = new SocketClient();
}
public void sendName(View view) {
String name = ((TextView) this.findViewById(R.id.editText1)).getText().toString();
if (name == "") {
Toast.makeText(this, getResources().getString(R.string.nameNull), Toast.LENGTH_SHORT).show();
return;
}
String sex = ((Spinner) this.findViewById(R.id.spinner1)).getSelectedItem().toString();
INFO = sex+ "." + name ;
new SocketThread(handler).start();
}
private class SocketThread extends Thread {
private Handler handler;
public SocketThread(Handler handler) {
super();
this.handler = handler;
}
@Override
public void run() {
Log.i("MySocketActivity", "SocketThead wait for result.");
String result = getSocketClient().sendMsg(INFO);
Log.i("MySocketActivity", "Socket reslut:" + result);
Message msg = handler.obtainMessage();
Bundle bundle = new Bundle();
bundle.putString("result", result);
msg.setData(bundle);
handler.sendMessage(msg);
}
}
private Handler handler = new Handler() {
public void handleMessage(android.os.Message msg) {
String result = msg.getData().getString("result");
Log.i("MySocketActivity", "Handler result:" + result);
((TextView) MySocketActivity.this.findViewById(R.id.tvResult)).setText(result);
};
};
@Override
protected void onDestroy() {
if (socketClient != null) {
getSocketClient().closeSocket();
}
super.onDestroy();
}
public SocketClient getSocketClient() {
if (socketClient == null) {
socketClient = new SocketClient();
}
return socketClient;
}
}