在Android上面如何使用带有心跳检测的Socket

由于移动设备的网络的复杂性，经常会出现网络断开，如果没有心跳包的检测，客户端只会在需要发送数据的时候才知道自己已经断线，会延误，甚至丢失服务器发送过来的数据。一下简单建立一个带有心跳检测的SocketDemo。

Android 后台Servevice

package org.feng.sockettest.server;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.ref.WeakReference;
import java.net.Socket;import java.net.UnknownHostException;
import java.util.Arrays;
import android.app.Service;
import android.content.Intent;
import android.os.Handler;
import android.os.IBinder;
import android.os.RemoteException;
import android.support.v4.content.LocalBroadcastManager;
import android.util.Log;

public class BackService extends Service { 
    private static final String TAG = "BackService"; 
    private static final long HEART_BEAT_RATE = 3 * 1000; 
    public static final String HOST = "192.168.1.101";// "192.168.1.21";// 
    public static final int PORT = 9800; 
    public static final String MESSAGE_ACTION="org.feng.message_ACTION"; 
    public static final String HEART_BEAT_ACTION="org.feng.heart_beat_ACTION"; 
    private ReadThread mReadThread; 
    private LocalBroadcastManager mLocalBroadcastManager;   
    private WeakReference<Socket> mSocket; // For heart Beat     
    private Handler mHandler = new Handler();
    private Runnable heartBeatRunnable = new Runnable() { 
        @Override 
        public void run() {
            if (System.currentTimeMillis() - sendTime >= HEART_BEAT_RATE) { 
                boolean isSuccess = sendMsg("");//就发送一个\r\n过去 如果发送失败，就重新初始化一个socket 
                if (!isSuccess) {                   
                mHandler.removeCallbacks(heartBeatRunnable);                    
                mReadThread.release();                  
                releaseLastSocket(mSocket); 
                new InitSocketThread().start();             
                }           
            }           
        mHandler.postDelayed(this, HEART_BEAT_RATE);
        }   
    }; 
    private long sendTime = 0L; 
    private IBackService.Stub iBackService = new IBackService.Stub() { 
        @Override 
        public boolean sendMessage(String message) throws RemoteException { 
            return sendMsg(message);        
        }   
    }; 

    @Override 
    public IBinder onBind(Intent arg0) { 
        return iBackService;    
    } 

    @Override 
    public void onCreate() { 
        super.onCreate(); 
        new InitSocketThread().start();     
        mLocalBroadcastManager=LocalBroadcastManager.getInstance(this);         
    } 
    public boolean sendMsg(String msg) { 
        if (null == mSocket || null == mSocket.get()) { 
            return false;       
        }       
        Socket soc = mSocket.get();
        try { 
            if (!soc.isClosed() && !soc.isOutputShutdown()) {
                OutputStream os = soc.getOutputStream();                
                String message = msg + "\r\n";                                  
                os.write(message.getBytes());               
                os.flush();             
                sendTime = System.currentTimeMillis();//每次发送成数据，就改一下最后成功发送的时间，节省心跳间隔时间 
            } else { 
                return false;           
            }       
        } catch (IOException e) {           
            e.printStackTrace(); 
            return false;       
        }
        return true;    
    } 
    private void initSocket() {
    //初始化Socket 
        try {           
            Socket so = new Socket(HOST, PORT);         
            mSocket = new WeakReference<Socket>(so);    
            mReadThread = new ReadThread(so);           
            mReadThread.start();            
            mHandler.postDelayed(heartBeatRunnable,             
            HEART_BEAT_RATE);//初始化成功后，就准备发送心跳包 
        } catch (UnknownHostException e) {
            e.printStackTrace();        
        } catch (IOException e) {           
            e.printStackTrace();        
        }   
    } 
    private void releaseLastSocket(WeakReference<Socket> mSocket){ 
        try { 
            if (null != mSocket) {              
                Socket sk = mSocket.get(); 
                if (!sk.isClosed()) {                   
                    sk.close();             
                }               
                sk = null;              
                mSocket = null;         
            }       
        } catch (IOException e) {           
            e.printStackTrace();        
        }   
    } 
    class InitSocketThread extends Thread { 
        @Override 
        public void run() { 
            super.run();            
            initSocket();       
        }   
    } 
    // Thread to read content from Socket 
    class ReadThread extends Thread { 
        private WeakReference<Socket> mWeakSocket; 
        private boolean isStart = true; 
        public ReadThread(Socket socket) {          
            mWeakSocket = new WeakReference<Socket>(socket);        
        } 
        public void release() {         
            isStart = false;            
            releaseLastSocket(mWeakSocket);     
        } 
        @Override 
        public void run() { 
            super.run();            
            Socket socket = mWeakSocket.get();
             if (null != socket) { 
                try {                   
                    InputStream is = socket.getInputStream(); 
                    byte[] buffer = new byte[1024 * 4];
                    int length = 0; 
                    while (!socket.isClosed() &&!socket.isInputShutdown()&& isStart && ((length = is.read(buffer)) != -1)) {
                        if (length > 0) {                           
                            String message = new String(Arrays.copyOf(buffer,length)).trim();                           
                            Log.e(TAG, message); //收到服务器过来的消息，就通过Broadcast发送出去 
                            if(message.equals("ok")){
                                //处理心跳回复 
                                Intent intent=new Intent(HEART_BEAT_ACTION);                                
                                mLocalBroadcastManager.sendBroadcast(intent);                           
                            }else{ 
                                //其他消息回复 
                                Intent intent=new Intent(MESSAGE_ACTION);                               
                                intent.putExtra("message", message);                                
                                mLocalBroadcastManager.sendBroadcast(intent);                           
                            }                       
                        }                   
                    }               
                } catch (IOException e) {                   
                    e.printStackTrace();                
                }           
            }       
        }   
    }
}

在Activity中发送以及接收数据：

package org.feng.sockettest;
import java.lang.ref.WeakReference;
import org.feng.sockettest.server.BackService;
import org.feng.sockettest.server.IBackService;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.os.RemoteException;
import android.support.v4.content.LocalBroadcastManager;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;


public class MainActivity extends Activity { 
    private static final String TAG = "MainActivity"; 
    private IBackService iBackService; 
    private ServiceConnection conn = new ServiceConnection() { 
        @Override 
        public void onServiceDisconnected(ComponentName name) {         
            iBackService = null;        
        } 
        @Override 
        public void onServiceConnected(ComponentName name, IBinder service) {           
            iBackService = IBackService.Stub.asInterface(service);      
        }   
    }; 
    private TextView mResultText; 
    private EditText mEditText; 
    private Intent mServiceIntent; 
    class MessageBackReciver extends BroadcastReceiver { 
        private WeakReference<TextView> textView; 
        public MessageBackReciver(TextView tv) {            
            textView = new WeakReference<TextView>(tv);     
        } 
        @Override 
        public void onReceive(Context context, Intent intent) {         
            String action = intent.getAction();         
            TextView tv = textView.get();
             if (action.equals(BackService.HEART_BEAT_ACTION)) { 
                if (null != tv) {                   
                    tv.setText("Get a heart heat");             
                }           
            } else {                
                String message = intent.getStringExtra("message");              
                tv.setText(message);            
            }       
        };  
    } 
    private MessageBackReciver mReciver; 
    private IntentFilter mIntentFilter; 
    private LocalBroadcastManager mLocalBroadcastManager; 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState);     
        setContentView(R.layout.activity_main);     
        mLocalBroadcastManager = LocalBroadcastManager.getInstance(this);       
        mResultText = (TextView) findViewById(R.id.resule_text);        
        mEditText = (EditText) findViewById(R.id.content_edit);     
        mReciver = new MessageBackReciver(mResultText);     
        mServiceIntent = new Intent(this, BackService.class);       
        mIntentFilter = new IntentFilter();     
        mIntentFilter.addAction(BackService.HEART_BEAT_ACTION);     
        mIntentFilter.addAction(BackService.MESSAGE_ACTION);    
    } 
    @Override 
    protected void onStart() { 
        super.onStart();        
        mLocalBroadcastManager.registerReceiver(mReciver, mIntentFilter);       
        bindService(mServiceIntent, conn, BIND_AUTO_CREATE);    
    } 
    @Override 
    protected void onStop() { 
        super.onStop();     
        unbindService(conn);        
        mLocalBroadcastManager.unregisterReceiver(mReciver);    
    } 
    public void onClick(View view) { 
        switch (view.getId()) { 
            case R.id.send:         
                String content = mEditText.getText().toString(); 
                try { 
                    boolean isSend = iBackService.sendMessage(content);//Send Content by socket 
                    Toast.makeText(this, isSend ? "success" : "fail",                       Toast.LENGTH_SHORT).show();             
                    mEditText.setText("");          
                } catch (RemoteException e) {               
                    e.printStackTrace();            
                } 
                break; 
            default: break;     
        }   
    }
}

完整项目带服务器段代码的见http://git.oschina.net/fengcunhan/SocketTest.git
该文章转载自：https://my.oschina.net/fengcunhan/blog/178155