Flutter table_calendarで日付を一度タップしないとマーカーが表示されない

前提・実現したいこと

Flutterでアプリを開発しています。
table_calendarを使いマーカーの表示機能を実装したい

ここに質問の内容を詳しく書いてください。
table_calendarを使いマーカーの表示機能を実装したいのですが、一度日付をタップしてから出ないとマーカーが表示されません。
画面表示時にマーカーを表示する方法をご教授いただきたいです。

該当のソースコード

dart
1class HomePage extends StatefulWidget {
2  @override
3  HomePageState createState() => HomePageState();
4}
5class HomePageState extends State<HomePage> {
6  DateTime _focusedDay = DateTime.now();
7  CalendarFormat _calendarFormat = CalendarFormat.month;
8  DateTime? _selectedDay;
9  DateTime? _getEventForDay;
10  Map<DateTime, List> _eventsList = {};
11  int getHashCode(DateTime key) {
12    return key.day * 1000000 + key.month * 10000 + key.year;
13  }
14
15  @override
16  void initState() {
17    super.initState();
18    const str = '2021-10-01';
19    final testDate = DateTime.parse(str);
20    _selectedDay = _focusedDay;
21
22  }
23  @override
24  Widget build(BuildContext context) {
25
26    DateTime? selectDate = new DateTime.now();
27
28    final _events = LinkedHashMap<DateTime, List>(
29      equals: isSameDay,
30      hashCode: getHashCode,
31    )..addAll(_eventsList);
32
33    List _getEventForDay(DateTime day) {
34      return _events[day] ?? [];
35    }
36
37    return  ChangeNotifierProvider<HomeModel>(
38      create: (_) => HomeModel()..fetchEventList(),
39      child: Scaffold(
40        body: Column(
41          children: [
42            Consumer<HomeModel>(
43              builder: (context, model, child) {
44                _eventsList = model.eventList;
45
46                
47                return TableCalendar(
48                  calendarStyle: CalendarStyle(
49                    selectedDecoration: BoxDecoration(
50                      color: Colors.pink[100],
51                      shape: BoxShape.circle,
52                    ),
53                    todayDecoration: BoxDecoration(
54                      color: Colors.deepOrange[200],
55                      shape: BoxShape.circle,
56                    ),
57                  ),
58                  headerStyle: const HeaderStyle(
59                    titleCentered: true,
60                    formatButtonVisible: false,
61                  ),
62                  firstDay: DateTime.utc(2010, 10, 16),
63                  lastDay: DateTime.utc(2030, 3, 14),
64                  focusedDay: DateTime.now(),
65                  eventLoader: _getEventForDay,
66                  locale: 'ja_JP',
67                  selectedDayPredicate: (day) {
68                    return isSameDay(_selectedDay, day);
69                  },
70                  onDaySelected: (selectedDay, focusedDay) {
71                    if (!isSameDay(_selectedDay, selectedDay)) {
72                      setState(() {
73                        _selectedDay = selectedDay;
74                        _focusedDay = focusedDay;
75                      });
76                      _getEventForDay(selectedDay);
77                    }
78                  },
79                  onPageChanged: (focusedDay) {
80                    _focusedDay = focusedDay;
81                  },
82                  calendarBuilders: CalendarBuilders(
83                    markerBuilder: (context, date, events) {
84                      if (events.isNotEmpty) {
85                        return _buildEventsMarker(date, events);
86                      }
87                    }
88                  ),
89                );
90              }
91            ),
92            ListView(
93              shrinkWrap: true,
94              children: _getEventForDay(_selectedDay!)
95                  .map((event) => ListTile(
96                        title: Text(event.toString()),
97                        onTap: () => {
98                          setState(() {
99                            selectDate = _selectedDay;
100                          })
101                        },
102                      ))
103                  .toList(),
104            ),
105            ButtonTheme(
106              child: ElevatedButton.icon(
107                style: ElevatedButton.styleFrom(
108                  primary: const Color.fromRGBO(250,167,176, 1),
109                  shape: const StadiumBorder(),
110                  onPrimary: Colors.white,
111                ),
112                icon: const Icon(Icons.edit_rounded),
113                label: const Text('記録'),
114                onPressed: () => {
115                  
116                },
117              ),
118            )
119          ]
120        ),
121      ),
122    );
123
124  }
125
126  Widget _buildEventsMarker(DateTime date, List events) {
127    return Positioned(
128      right: 5,
129      bottom: 5,
130      child: AnimatedContainer(
131        duration: const Duration(milliseconds: 300),
132        decoration: const BoxDecoration(
133          shape: BoxShape.circle,
134          color: Color.fromRGBO(250,167,176, 1),
135        ),
136        width: 16.0,
137        height: 16.0,
138        child: Center(
139          child: Text(
140            '${events.length}',
141            style: const TextStyle().copyWith(
142              color: Colors.white,
143              fontSize: 12.0,
144            ),
145          ),
146        ),
147      ),
148    );
149  }
150}