android - 定期任务的 ScheduledThreadPoolExecutor(使用 Retrofit)只触发一次，永远不会再触发

Question

我有以下代码用于每 X 秒从服务器轮询一次未读通知计数

我通过 App.onCreate() 中的 ScheduledThreadPoolExecutor 开始这个过程，

Log.d("XXX", "Requesting Notification count from server ...");

被调用一次(我可以在 Logcat 中看到)，但是两个 Retrofit 回调函数都没有被调用(实际上没有 Retrofit 调试日志)。此外，“从服务器请求通知计数......”再也不会打印出来(即周期性任务未运行)

我也将 Retrofit 用于其他网络服务调用(根据用户输入)并且它们工作正常(我可以在 logcat 中看到传入和传出的请求/响应)

public class App extends Application  {



    private ScheduledExecutorService scheduleTaskExecutor;
    ...


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

        //region Set up the periodic notification count listener task


        scheduleTaskExecutor= Executors.newScheduledThreadPool(2);
        scheduleTaskExecutor.scheduleAtFixedRate(new PeriodicNotifCountFetchTask(), 0, 5, TimeUnit.SECONDS);

        //endregion
    }


    class PeriodicNotifCountFetchTask implements Runnable {

        @Override
        public void run() {
            Log.d("XXX", "Requesting Notification count from server ...");
            EMRestClient.getmEMRestService().getNotificationCount(new Callback<NotificationCount>() {
                @Override
                public void success(NotificationCount response, Response unused) {

                    int unreadNotifCount = response.getCount();

                    Log.d("XXX", "Successfully fetched notification count, unread = " + response.getCount());
                    if (unreadNotifCount>0){
                        // call listener to repaint menu
                        for (NewNotificationListener x :notifListeners){
                            x.onNewNotificationReceived(response.getCount());    
                        }
                    }
                }

                @Override
                public void failure(RetrofitError error) {
                    Log.d("XXX", "Failed to fetch notification count from server");
                }
            });

        }
    }


}

改造部分代码在这里:

    @POST("/notification/notification_count/")
    void getNotificationCount(Callback<NotificationCount> callback);

Answer 1

可能会出现一些异常，因为后续调用将被抑制。 ScheduledThreadPoolExecutor only "ticking" once

所以试着把你的代码放在 runOnUiThread 的 runnable 里面，比如 Scheduling recurring task in Android