sqlite - 在SQLite Flutter中单击按钮时如何显示当前日期时间？

Question

This is My App

我想在添加新名称时添加一个包含当前日期的新列，这对我的代码有帮助吗？
此类添加名称

class Employee {
  int id;
  String name;

  Employee(this.id, this.name);

  Map<String, dynamic> toMap() {
    var map = <String, dynamic>{
      'id': id,
      'name': name,
    };
    return map;
  }

  Employee.fromMap(Map<String, dynamic> map) {
    id = map['id'];
    name = map['name'];
  }
}

这是我用来存储名称并显示删除按钮的数据库，如何在添加新名称时在此处添加包含当前日期时间的新列？

强文本

Future<List<Employee>> employees;
  TextEditingController controller = TextEditingController();
  String name;
  int curUserId;

  final formKey = new GlobalKey<FormState>();
  var dbHelper;
  bool isUpdating;

  @override
  void initState() {
    super.initState();
    dbHelper = DBHelper();
    isUpdating = false;
    refreshList();
  }

  refreshList() {
    setState(() {
      employees = dbHelper.getEmployees();
    });
  }

  clearName() {
    controller.text = '';
  }

  validate() {
    if (formKey.currentState.validate()) {
      formKey.currentState.save();
      if (isUpdating) {
        Employee e = Employee(curUserId, name);
        dbHelper.update(e);
        setState(() {
          isUpdating = false;
        });
      } else {
        Employee e = Employee(null, name);
        dbHelper.save(e);
      }
      clearName();
      refreshList();
    }
  }

  form() {
    return Form(
      key: formKey,
      child: Padding(
        padding: EdgeInsets.all(15.0),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          mainAxisSize: MainAxisSize.min,
          verticalDirection: VerticalDirection.down,
          children: <Widget>[
            TextFormField(
              controller: controller,
              keyboardType: TextInputType.text,
              decoration: InputDecoration(labelText: 'Name'),
              validator: (val) => val.length == 0 ? 'Enter Name' : null,
              onSaved: (val) => name = val,
            ),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              children: <Widget>[
                FlatButton(
                  onPressed: validate,
                  child: Text(isUpdating ? 'UPDATE' : 'ADD'),
                ),
                FlatButton(
                  onPressed: () {
                    setState(() {
                      isUpdating = false;
                    });
                    clearName();
                  },
                  child: Text('CANCEL'),
                )
              ],
            ),
          ],
        ),
      ),
    );
  }

  SingleChildScrollView dataTable(List<Employee> employees) {
    return SingleChildScrollView(
      scrollDirection: Axis.vertical,
      child: DataTable(
        columns: [
          DataColumn(
            label: Text('NAME'),
          ),
          DataColumn(
            label: Text('DELETE'),
          ),
        //  DataColumn(label: Text("")'null')

        ],
        rows: employees
            .map(
              (employee) => DataRow(cells: [
                    DataCell(
                      Text(employee.name),
                      onTap: () {
                        setState(() {
                          isUpdating = true;
                          curUserId = employee.id;
                        });
                        controller.text = employee.name;
                      },
                    ),
                    DataCell(IconButton(
                      icon: Icon(Icons.delete),
                      onPressed: () {
                        dbHelper.delete(employee.id);
                        refreshList();
                      },
                    )),
                  ]),
            )
            .toList(),
      ),
    );
  }

  list() {
    return Expanded(
      child: FutureBuilder(
        future: employees,
        builder: (context, snapshot) {
          if (snapshot.hasData) {
            return dataTable(snapshot.data);
          }

          if (null == snapshot.data || snapshot.data.length == 0) {
            return Text("No Data Found");
          }

          return CircularProgressIndicator();
        },
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(

      title: new Text('Stay_Safe'),
      centerTitle: true
      ),
      body: new Container(
        child: new Column(
          mainAxisAlignment: MainAxisAlignment.start,
          mainAxisSize: MainAxisSize.min,
          verticalDirection: VerticalDirection.down,
          children: <Widget>[
            form(),
            list(),
          ],
        ),
      ),
    );
  }
}

Answer 1

将DateTime添加到Employee模型:

class Employee {
  int id;
  String name;
  DateTime dateTime;

  Employee(this.id, this.name, this.dateTime);

  Map<String, dynamic> toMap() {
    final Map<String, dynamic> map = new Map<String, dynamic>();
    map['id'] = this.id;
    map['name'] = this.name;
    map['dateTime'] = dateTime != null ? this.dateTime.toIso8601String() : '';
    return map;
  }

  Employee.fromMap(Map<String, dynamic> map) {
    id = map['id'];
    name = map['name'];
    dateTime = map['dateTime'] != null? DateTime.parse(map['dateTime']): null;
  }
}

DateTime.now()返回用户当前的DateTime。每当用户更新或添加新数据时我们都将传递它。我们将创建另一个数据列和单元格来显示时间.datetime需要转换为可显示的字符串，因此我们将使用自定义函数getFormattedDate，最后在Text小部件中显示它。

Future<List<Employee>> employees;
TextEditingController controller = TextEditingController();
String name;
int curUserId;

final formKey = new GlobalKey<FormState>();
var dbHelper;
bool isUpdating;

@override
void initState() {
  super.initState();
  dbHelper = DBHelper();
  isUpdating = false;
  refreshList();
}

refreshList() {
  setState(() {
    employees = dbHelper.getEmployees();
  });
}

clearName() {
  controller.text = '';
}

validate() {
  if (formKey.currentState.validate()) {
    formKey.currentState.save();
    if (isUpdating) {
      Employee e = Employee(curUserId, name,DateTime.now());
      dbHelper.update(e);
      setState(() {
        isUpdating = false;
      });
    } else {
      Employee e = Employee(null, name,DateTime.now());
      dbHelper.save(e);
    }
    clearName();
    refreshList();
  }
}

form() {
  return Form(
    key: formKey,
    child: Padding(
      padding: EdgeInsets.all(15.0),
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        mainAxisSize: MainAxisSize.min,
        verticalDirection: VerticalDirection.down,
        children: <Widget>[
          TextFormField(
            controller: controller,
            keyboardType: TextInputType.text,
            decoration: InputDecoration(labelText: 'Name'),
            validator: (val) => val.length == 0 ? 'Enter Name' : null,
            onSaved: (val) => name = val,
          ),
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            children: <Widget>[
              FlatButton(
                onPressed: validate,
                child: Text(isUpdating ? 'UPDATE' : 'ADD'),
              ),
              FlatButton(
                onPressed: () {
                  setState(() {
                    isUpdating = false;
                  });
                  clearName();
                },
                child: Text('CANCEL'),
              )
            ],
          ),
        ],
      ),
    ),
  );
}

SingleChildScrollView dataTable(List<Employee> employees) {
  return SingleChildScrollView(
    scrollDirection: Axis.vertical,
    child: DataTable(
      columns: [
        DataColumn(
          label: Text('NAME'),
        ),
        DataColumn(
          label: Text('DELETE'),
        ),
        DataColumn(
          label: Text('DATE'),
        ),
        //  DataColumn(label: Text("")'null')

      ],
      rows: employees
          .map(
            (employee) => DataRow(cells: [
          DataCell(
            Text(employee.name),
            onTap: () {
              setState(() {
                isUpdating = true;
                curUserId = employee.id;
              });
              controller.text = employee.name;
            },
          ),
          DataCell(IconButton(
            icon: Icon(Icons.delete),
            onPressed: () {
              dbHelper.delete(employee.id);
              refreshList();
            },
          )),
              DataCell(

                Text(((DateTime date) =>
                "${date.hour % 12}:${date.minute} ${date.hour > 12
                    ? 'PM'
                    : 'AM'}")(
                    employee.dateTime) + ' ${getFormattedDate(employee.dateTime.toIso8601String())}'),
                onTap: () {
                  //Any action
                },
              ),
        ]),
      )
          .toList(),
    ),
  );
}

list() {
  return Expanded(
    child: FutureBuilder(
      future: employees,
      builder: (context, snapshot) {
        if (snapshot.hasData) {
          return dataTable(snapshot.data);
        }

        if (null == snapshot.data || snapshot.data.length == 0) {
          return Text("No Data Found");
        }

        return CircularProgressIndicator();
      },
    ),
  );
}

@override
Widget build(BuildContext context) {
  return new Scaffold(
    appBar: new AppBar(

        title: new Text('Stay_Safe'),
        centerTitle: true
    ),
    body: new Container(
      child: new Column(
        mainAxisAlignment: MainAxisAlignment.start,
        mainAxisSize: MainAxisSize.min,
        verticalDirection: VerticalDirection.down,
        children: <Widget>[
          form(),
          list(),
        ],
      ),
    ),
  );
}


String getFormattedDate(String date) {
  var d = DateTime.parse(date);
  return   [
    "Jan",
    "Feb",
    "Mar",
    "Apr",
    "May",
    "Jun",
    "Jul",
    "Aug",
    "Sep",
    "Oct",
    "Nov",
    "Dec"
  ][d.month - 1] +
      " " +   d.day.toString() +
      "," +
      d.year.toString();
}