database - 颤振中的所有音符都显示相同的日期。日期未动态更新

Question

我是 Flutter 的初学者，我正在构建一个简单的笔记应用程序。每当用户创建便笺时，创建日期的月份和年份将被插入到 SQflite DB 中，我在主屏幕上获取相同的内容。但对于所有其他笔记，也会显示相同的日期月份和年份。不知道哪里出错了，求大神帮忙。在过去的两天里，我陷入了困境。我已经检查了 StackOverflow 中的其他答案，从那里我了解了 date 的实现，但无法解决这个问题。

数据库助手类

import 'package:path/path.dart';
import 'package:sqflite/sqflite.dart';
import 'model_notes.dart';

class DatabaseHelper {
  static final _databaseName = "myNote.db";
  static final _databaseVersion = 1;
  static final table = 'notes_table';
  static final columnId = 'id';
  static final columnTitle = 'title';
  static final columnBody = 'body';
  static final columnDate = 'date';

  DatabaseHelper._privateConstructor();

  static final DatabaseHelper instance = DatabaseHelper._privateConstructor();
  static Database _database;

  Future<Database> get database async {
    if (_database != null) return _database;
    _database = await initDatabase();
    return _database;
  }

  initDatabase() async {
    String path = join(await getDatabasesPath(), _databaseName);
    return await openDatabase(path,
        version: _databaseVersion, onCreate: _onCreate);
  }

  Future _onCreate(Database db, int version) async {
    await db.execute('''
          CREATE TABLE $table (
            $columnId INTEGER PRIMARY KEY AUTOINCREMENT,
            $columnTitle TEXT NOT NULL,
            $columnBody TEXT NOT NULL,
            $columnDate TEXT NOT NULL
          )
          ''');
  }

  Future<int> insert(Note note) async {
    Database db = await instance.database;
    if (note.title.trim().isEmpty) note.title = 'Untitled Note';
    return await db.insert(table, {'title': note.title, 'body': note.body, 'date': note.date});
  }

  Future<List<Note>> getNotesFromDB() async {
    final db = await database;
    List<Note> notesList = [];
    List<Map> maps = await db.query(table);
    if (maps.length > 0) {
      maps.forEach((map) {
        notesList.add(Note.fromMap(map));
      });
    }
    return notesList;
  }
}

这是我的笔记模型类

import 'db_operations.dart';

class Note {
  int id;
  String title;
  String body;
  String date;

  Note(this.id, this.title, this.body, this.date);

  Note.fromMap(Map<String, dynamic> map) {
    id = map['id'];
    title = map['title'];
    body = map['body'];
    date = map['date'];
  }

  Map<String, dynamic> toMap() {
    return {
      DatabaseHelper.columnId: id,
      DatabaseHelper.columnTitle: title,
      DatabaseHelper.columnBody: body,
      DatabaseHelper.columnDate: date,
    };
  }

  @override
  String toString() {
    return '$title, $date';
  }
}

这是我添加注释的地方

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:note_taking_app/constants/buttons_and_icons_misc(classes).dart';
import 'package:note_taking_app/db/db_operations.dart';
import 'package:note_taking_app/db/model_notes.dart';

final bodyController = TextEditingController();
final headerController = TextEditingController();
final dbHelper = DatabaseHelper.instance;
String formattedDate = DateFormat.yMMMd('en_US').format(DateTime.now());

class AddingNotes extends StatefulWidget {
  @override
  _AddingNotesState createState() => _AddingNotesState();
}

class _AddingNotesState extends State<AddingNotes> {
  @override
  void initState() {
    super.initState();
    bodyController.clear();
    headerController.clear();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        elevation: 0,
        backwardsCompatibility: true,
        leading: LeadingIcon(
          callBack: () {
            Navigator.pop(context);
          },
        ),
        backgroundColor: Colors.white.withOpacity(0.4),
        actions: <Widget>[
          ActionsIconButton(
            icon: Icon(undo, color: black),
            callBack: () {
              debugPrint('undo tapped');
            },
          ),
          ActionsIconButton(
            icon: Icon(redo, color: black),
            callBack: () {
              debugPrint('redo tapped');
            },
          ),
          ActionsIconButton(
            icon: Icon(save, color: black),
            callBack: () async {
              String title = headerController.text;
              String body = bodyController.text;
              Note note = Note(20, title, body, formattedDate);
              var value = await dbHelper.insert(note);            
              Navigator.pop(context);
            },
          )
        ],
      ),
      body: Container(
        color: Colors.white.withOpacity(0.4),
        child: Padding(
          padding: const EdgeInsets.all(13.0),
          child: Column(
            children: [
              HeaderBody(
                textEditingController: headerController,
              ),
              SizedBox(
                height: 32.0,
              ),
              Expanded(
                child: NotesBody(
                  textEditingController: bodyController,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

这是我显示笔记的地方

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:intl/intl.dart';
import 'package:note_taking_app/constants/buttons_and_icons_misc(classes).dart';
import 'package:note_taking_app/constants/text_and_decorations(methods).dart';
import 'package:note_taking_app/db/model_notes.dart';
import 'package:note_taking_app/ui/adding_notes.dart';

class MainScreen extends StatefulWidget {
  @override
  _MainScreenState createState() => _MainScreenState();
}

class _MainScreenState extends State<MainScreen> {
  List<Note> noteList = [];

  @override
  void initState() {
    super.initState();
    dbHelper.initDatabase();
    setNotesFromDB();
  }

  setNotesFromDB() async {
    print("Entered setNotes in main page");
    var fetchedNotes = await dbHelper.getNotesFromDB();
    setState(() {
      noteList = fetchedNotes;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: mainScreenAppBar,
      floatingActionButton: FAB(
        whatToDo: () {
          gotoAddingNotesPage(context);
        },
      ),
      body: SafeArea(
        child: ListView.builder(
          itemCount: noteList.length,
          itemBuilder: (context, index) {
            return TileCard(
              titleText: ('${noteList[index].title}'),
              dateText: ('${noteList[index].date}'),
            );
          },
        ),
      ),
    );
  }

  gotoAddingNotesPage(BuildContext context) {
    Navigator.push(
      context,
      MaterialPageRoute(builder: (context) => AddingNotes()),
    ).then((value) => setState(() {
          setNotesFromDB();
        }));
  }
}

这是我声明 dateText 小部件的 TileCard 类

class TileCard extends StatelessWidget {
  final String titleText;
  final String dateText;

  const TileCard({@required this.titleText, @required this.dateText});

  @override
  Widget build(BuildContext context) {
    return Container(
      height: 90,
      child: Card(
        shape:
            RoundedRectangleBorder(borderRadius: BorderRadius.circular(12.0)),
        elevation: 0,
        margin: const EdgeInsets.all(8.0),
        child: ListTile(
          shape:
              RoundedRectangleBorder(borderRadius: BorderRadius.circular(12.0)),
          title: Text(
            titleText,
            style: TextStyle(fontWeight: FontWeight.w700),
          ),
          tileColor: Colors.grey.withOpacity(0.2),
          subtitle: Padding(
            padding: EdgeInsets.only(top: 10.0),
            child: Text(dateText),
          ),
        ),
      ),
    );
  }
}

我添加了图像，这就是现在的样子。

标签： databasesqlitedatetimeflutter-dependenciessqflite