如何在加载其余小部件之前执行函数 onPressed()？

Question

所以我有一个异步函数，当我从日历中单击某一天时会执行该函数。如果在数据库中有那天存储的信息，我将结果添加到列表任务中。这是那个函数

// This code is suppose to get all the taskNames of user on clicked day
  Future<void> getUserEvents() async {
    //We get Collection of 'userAssignments' from database
    final CollectionReference userAssignments =
        Firestore.instance.collection('userAssignments');

    //We get current logged in user
    FirebaseUser user = await FirebaseAuth.instance.currentUser();

    //This is used to format a DateTime of selected day to String 'yyyy-MM-dd'
    var formater = new DateFormat('yyyy-MM-dd');
    String formatted = formater.format(_controller.selectedDay);

    //We get rid off a all the unneded data from list
    tasks.clear();

    //This is a query, We loop through entire collection and we look for a document
    // with email of logged in user and we look for a day that is
    // equal to selected formated day (variable formatted)

    userAssignments
        .where("userEmail", isEqualTo: user.email)
        .where("eventDayForCalendar", isEqualTo: formatted)
        .snapshots()
        .listen((data) => data.documents.forEach((doc) {

              // We get a taskName from that document and we add it to our local List tasks
              String taskName = doc["taskName"];

              tasks.add(taskName);
            }));
  }

这里是小部件的代码。在代码的最下面，Column负责为List任务中的每个元素显示一张卡片。

//This is the class in which you can initialize widgets
class _CalendarPageState extends State<CalendarPage> {
  final DatabaseService _dbServices = DatabaseService();
  final AuthService _auth = AuthService();

  //This List stores all found tasks while conducting a getUserEvents()
  List<String> tasks = new List<String>();

//Here is placed the code from above

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      //This creates a box that sorrounds the calendar and makes it scrollable
      body: SingleChildScrollView(
        child: Column(
          children: <Widget>[
            TableCalendar(
              events: _events,
              //Set the calendar controler parameter
              calendarController: _controller,
              //Set the starting day of the week to monday
              startingDayOfWeek: StartingDayOfWeek.monday,
              //Set default calendar format to week
              initialCalendarFormat: CalendarFormat.week,
              onDaySelected: (day, events) async {

                //Here i call the function that executes query and 
                // stores results in list tasks
                await getUserEvents();
                setState(() {
                  _selectedEvents = events;
                });
              },
              //Start defining the calendar style
              calendarStyle: CalendarStyle(
                todayColor: Colors.green,
                selectedColor: Colors.blue,
              ),
              headerStyle: HeaderStyle(
                titleTextStyle: TextStyle(
                  fontWeight: FontWeight.bold,
                  fontSize: 20,
                ),
                //Hide the formatter for week/month
                formatButtonShowsNext: false,
                formatButtonVisible: false,
                centerHeaderTitle: true,
              ),
            ),
            Column(
                children: tasks
                    .map((i) => new Card(
                            child: ListTile(
                          title: Text(i.toString()),
                          leading: Icon(Icons.assignment_turned_in),
                        )))
                    .toList())
          ],
        ),
      ),
   
    );
  }

This is how it looks when function loads in before Column Widget

And this is how it looks on the same day if widget loads in before function is completed

是否可能有一个小部件可以暂停代码在他下面或他内部执行？

Answer 1

我认为如果您在 getUserEvents() 的末尾添加 setState((){ tasks =tasks; }); 小部件应该重建。