奥利奥失败的前台服务

Question

我正在尝试为Oreo及其以上版本创建一个简单的小部件，以便在定期点击时重新加载其数据。以下是我的大纲代码：

public class WodWidget extends AppWidgetProvider {

    @Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
        updateWodWidget(context);
    }

    static void updateWodWidget(Context context) {
        context.startForegroundService(new Intent(context, UpdateService.class));
    }

    public static class UpdateService extends IntentService {
        private static final String TAG = "WodWidgetUpdateService";
        private final Handler mHandler = new Handler();

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

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

            String channelId = "foobar";
            String channelName = "Widget update service";
            NotificationChannel channel = new NotificationChannel(channelId, channelName, NotificationManager.IMPORTANCE_NONE);
            NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
            manager.createNotificationChannel(channel);

            Notification notification = new Notification.Builder(getApplicationContext())
                .setChannelId(channelId)
                .setContentTitle("notification title")
                .setContentText("notification content")
                .build();

            startForeground(1, notification);
        }
        @Override
        protected void onHandleIntent(Intent intent) {
            if (Clicks.ACTION_CLICK.equals(intent.getAction())) {
                Clicks.handleClickAction(this, mHandler);
            } else {
                getWodData(this);
            }
        }

        protected void getWodData(final Context context) {
            WodData.getInstance().invalidate();
            WodWidget.updateViews(context);

            GetHTMLTask task = new GetHTMLTask(new GetHTMLTask.OnTaskCompleted() {
                @Override
                public void onTaskCompleted() {
                    WodWidget.updateViews(context);
                }
            });
            task.execute(WodData.PARSE_URL);
        }
    }
    static void singleClickHandler(Context context) {
        updateWodWidget(context);
    }

    static void doubleClickHandler(Context context) { [...] }

    private static void updateViews(Context context) {
        RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.wod_widget);
        WodData wd = WodData.getInstance();

        view    s.setTextViewText(R.id.appwidget_text, "foobar");
        Intent intent = new Intent(Clicks.ACTION_CLICK, null, context, UpdateService.class);
        PendingIntent pendingIntent = PendingIntent.getService(context, 0, intent, 0);
        views.setOnClickPendingIntent(R.id.layoutWidget, pendingIntent);

        ComponentName thisWidget = new ComponentName(context, WodWidget.class);
        AppWidgetManager.getInstance(context).updateAppWidget(thisWidget, views);
    }
}

现在这个构建并运行良好，有一段时间，也可以单击小部件。但是过了一会儿（几分钟左右），点击不再刷新小部件了，我在logcat中看到以下条目：

W/ActivityManager: Background start not allowed: service Intent { act=com.mywidget.action.CLICK flg=0x10000000 cmp=com.mywidget/.WodWidget$UpdateService bnds=[56,367][620,1111] } to com.mywidget/.WodWidget$UpdateService from pid=-1 uid=10083 pkg=com.mywidget

所以我猜它正在成为后台服务而不是前台服务，但为什么以及如何防止这种情况发生呢？