XmppManager

private void addTask(Runnable runnable) {
		Log.d(LOGTAG, "addTask(runnable)...");
		taskTracker.increase();
		synchronized (taskList) {
			if (taskList.isEmpty() && !running) {
				running = true;
				futureTask = taskSubmitter.submit(runnable);
				if (futureTask == null) {
					taskTracker.decrease();
				}
			} else {
				/**
				 * runTask(); 解決伺服器端重啟後,客戶端不能成功連線 Androidpn 伺服器
				 */
				runTask();
				taskList.add(runnable);
			}
		}
		Log.d(LOGTAG, "addTask(runnable)... done");
	}