android 一个简单的服务例子

 public class MessageService extends Service {

     // 获取消息线程
     private MessageThread messageThread = null;

     // 点击查看
     private Intent messageIntent = null;
     private PendingIntent messagePendingIntent = null;

     // 通知栏消息
     private int messageNotificationID = 1000;
     private Notification messageNotification = null;
     private NotificationManager messageNotificatioManager = null;
     private final IBinder binder = new MessageService.LocalBinder();

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

     // 定义内容类继承Binder
     class LocalBinder extends Binder {
         // 返回本地服务
         // 可以返回这个服务，然后<bold>activity可以通过服务调用服务的方法</bold>了。
         MessageService getService() {
             return MessageService.this;
         }

     }

     @Override
     public int onStartCommand(final Intent intent, final int flags,
             final int startId) {
         // 初始化
         messageNotification = new Notification();
         messageNotification.icon = R.drawable.ic_launcher;
         messageNotification.tickerText = "新消息";
         messageNotification.defaults = Notification.DEFAULT_SOUND;
         messageNotificatioManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

         messageIntent = new Intent(this, MessageActivity.class);
         messagePendingIntent = PendingIntent.getActivity(this, 0,
                 messageIntent, 0);

         // 开启线程
         messageThread = new MessageThread();
         messageThread.isRunning = true;
         messageThread.start();

         return super.onStartCommand(intent, flags, startId);
     }

     /**
      * 从服务器端获取消息
      *
      */
     class MessageThread extends Thread {
         // 运行状态，下一步骤有大用
         public boolean isRunning = true;

         @Override
         public void run() {
             while (isRunning) {
                 try {
                     // 休息15s
                     Thread.sleep(15 * 1000);
                     // 获取服务器消息
                     String serverMessage = getServerMessage();
                     if (serverMessage != null && !"".equals(serverMessage)) {
                         // 更新通知栏
                         messageNotification.setLatestEventInfo(
                                 MessageService.this, "新消息", "奥巴马宣布,本拉登兄弟挂了!"
                                         + serverMessage, messagePendingIntent);
                         messageNotificatioManager.notify(messageNotificationID,
                                 messageNotification);
                         // 每次通知完，通知ID递增一下，避免消息覆盖掉
                         messageNotificationID++;
                     }
                 } catch (InterruptedException e) {
                     e.printStackTrace();
                 }
             }
         }
     }

     /**
      * 这里以此方法为服务器Demo，仅作示例
      *
      * @return 返回服务器要推送的消息，否则如果为空 的话，不推送
      */
     public String getServerMessage() {
         return "YES!";
     }

     @Override
     public void onDestroy() {
         System.exit(0);
         // 或者，二选一，推荐使用System.exit(0)，这样进程退出的更干净
         // messageThread.isRunning = false;
         super.onDestroy();
     }
 }

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