原生时间组件

获取选中的时间采用异步的方式，有两种，分别为
Function().then(value{ })
async + value = await Function()

在yaml文件中添加依赖 date_format: ^1.0.8
获取当前时间 DateTime.now()
转换成时间戳 .millisecondsSinceEpoch
时间戳转化为时间 DateTime.fromMillisecondsSinceEpoch()

class _TimeDemoState extends State<TimeDemo> {DateTime _nowDate=DateTime.now();TimeOfDay _nowTime=TimeOfDay(hour: 11, minute: 11);_showDatePicker(){showDatePicker(context: context, initialDate: _nowDate, firstDate: DateTime(2010), lastDate: DateTime(2030),).then((value){setState(() {if (value!=null) _nowDate=value;});});}_showTimePicker() async {var nowtime=await showTimePicker(context: context, initialTime: _nowTime,);setState(() {if (nowtime!=null) _nowTime=nowtime;});}@overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(title: Text('Student Info System'),),body: Column(mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[Row(mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[InkWell(child: Row(mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[Text('${formatDate(_nowDate, [yyyy, '/', mm, '/', dd])}'),Icon(Icons.arrow_drop_down),],),onTap: _showDatePicker,),SizedBox(width: 40),InkWell(child: Row(mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[Text('${_nowTime.format(context)}'),Icon(Icons.arrow_drop_down),],),onTap: _showTimePicker,),],),],),);}
}

第三方时间组件flutter_cupertino_date_picker

class _TimeDemoState extends State<TimeDemo> {DateTime _dateTime=DateTime.now();_showDatePicker() {DatePicker.showDatePicker(context,onMonthChangeStartWithFirstDate: false,pickerTheme: DateTimePickerTheme(showTitle: true,confirm: Text('Done', style: TextStyle(color: Colors.red)),cancel:  Text('Cancel'),),minDateTime: DateTime.parse('2010-01-01'),maxDateTime: DateTime.parse('2030-12-31'),initialDateTime: _dateTime,locale: DateTimePickerLocale.zh_cn,onClose: () => print("----- onClose -----"),onCancel: () => print('onCancel'),onChange: (dateTime, List<int> index) {},onConfirm: (dateTime, List<int> index) {setState(() {_dateTime = dateTime;});},);}_showDateTimePicker() {DatePicker.showDatePicker(context,minDateTime: DateTime.parse('2019-05-15 09:23:10'),maxDateTime: DateTime.parse('2029-06-03 21:11:00'),initialDateTime: DateTime.now(),dateFormat: 'yyyy年M月d日    EEEE,H时 m分',locale: DateTimePickerLocale.zh_cn,pickerTheme: DateTimePickerTheme(showTitle: true,),pickerMode: DateTimePickerMode.datetime, // show TimePickeronCancel: () {debugPrint('onCancel');},onChange: (dateTime, List<int> index) {},onConfirm: (dateTime, List<int> index) {setState(() {_dateTime = dateTime;});},);}@overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(title: Text('Student Info System'),),body: Column(mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[Row(mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[InkWell(child: Row(mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[Text('${formatDate(_dateTime,  [yyyy, '/', mm, '/', dd])}'),Icon(Icons.arrow_drop_down),],),onTap: _showDatePicker,     ),],),Row(mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[InkWell(child: Row(mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[Text('${formatDate(_dateTime,[yyyy, '年', mm, '月', dd,'日     ',HH,'时',nn,'分'])}'),Icon(Icons.arrow_drop_down),],),onTap: _showDateTimePicker,     ),],),],),);}
}