Android 后台Service : 向服务器发送心跳包

public class HeartbeatService extends Service implements Runnable
{
    private Thread          mThread;
    public int              count           = 0;
    private boolean         isTip           = true;
    private static String   mRestMsg;
    private static String   KEY_REST_MSG    = "KEY_REST_MSG";

    @Override
    public void run()
    {
        while (true)
        {
            try
            {
                if (count > 1)
                {
                    Log.i("@qi", "offline");
                    count = 1;
                    if (isTip)
                    {
                        //判断应用是否在运行
                        ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
                        List<RunningTaskInfo> list = am.getRunningTasks(3);
                        for (RunningTaskInfo info : list)
                        {
                            if (info.topActivity.getPackageName().equals("org.yhn.demo"))
                            {
                                //通知应用，显示提示“连接不到服务器”
                                Intent intent = new Intent("org.yhn.demo");
                                intent.putExtra("msg", true);
                                sendBroadcast(intent);
                                break;
                            }
                        }

                        isTip = false;
                    }
                }
                if (mRestMsg != "" && mRestMsg != null)
                {
                    //向服务器发送心跳包
                    sendHeartbeatPackage(mRestMsg);
                    count += 1;
                }

                Thread.sleep(1000 * 3);
            }
            catch (InterruptedException e)
            {
                e.printStackTrace();
            }
        }
    }

    private void sendHeartbeatPackage(String msg)
    {
        HttpGet httpGet = new HttpGet(msg);
        DefaultHttpClient httpClient = new DefaultHttpClient();
        // 发送请求
        HttpResponse httpResponse = null;
        try
        {
            httpResponse = httpClient.execute(httpGet);
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        if (httpResponse == null)
        {
            return;
        }

        // 处理返回结果
        final int responseCode = httpResponse.getStatusLine().getStatusCode();
        if (responseCode == HttpStatus.SC_OK)
        {
            //只要服务器有回应就OK
            count = 0;
            isTip = true;
        }
        else
        {
            Log.i("@qi", "responseCode " + responseCode);
        }

    }

    @Override
    public IBinder onBind(Intent intent)
    {
        return null;
    }


    @Override
    public void onCreate()
    {
        super.onCreate();
    }



    @Override
    public void onDestroy()
    {
        super.onDestroy();
    }

    public void onStart(Intent intent, int startId)
    {
        Log.i("@qi", "service onStart");
        //从本地读取服务器的URL，如果没有就用传进来的URL
        mRestMsg = getRestMsg();
        if (mRestMsg == null || mRestMsg == "")
        {
            mRestMsg = intent.getExtras().getString("url");
        }
        setRestMsg(mRestMsg);

        mThread = new Thread(this);
        mThread.start();
        count = 0;

        super.onStart(intent, startId);
    }

    public String getRestMsg()
    {
        SharedPreferences prefer = getSharedPreferences("settings.data", Context.MODE_PRIVATE);
        Log.i("@qi", "getRestMsg() " + prefer.getString(KEY_REST_MSG, ""));
        return prefer.getString(KEY_REST_MSG, "");
    }

    public void setRestMsg(String restMsg)
    {
        SharedPreferences prefer = getSharedPreferences("settings.data", Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = prefer.edit();
        editor.putString(KEY_REST_MSG, restMsg);
        editor.commit();
    }

}

启动Service：

Intent serviceIntent = new Intent("HeartbeatService");
serviceIntent.putExtra("url",url);
startService(serviceIntent);

最后别忘了注册Server和GET_TASKS

<service
            android:name=".demo.HeartbeatService"
            android:label="QServer"
            android:persistent="true" >
            <intent-filter>
                <action android:name="HeartbeatService" />
            </intent-filter>
        </service>

<uses-permission android:name="android.permission.GET_TASKS" />

运行效果：

来源：http://blog.csdn.net/vestigge/article/details/8563447