Как выполнять CRUD-операции с шаблоном BLo C? - PullRequest
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Как выполнять CRUD-операции с шаблоном BLo C?

0 голосов
/ 07 февраля 2020

Я изучал на флаттере, как выполнять CRUD-операции, используя паттерн BLo C, я увидел онлайн-учебник и попытался его применить. C, R, U в порядке, но удаление не работает. это исходный код Пожалуйста помоги !

файл todo_blo c .dart 

import 'package:zencartos/models/todo.dart';
import 'package:zencartos/repository/todo_repository.dart';

class TodoBloc {
  //Get instance of the Repository
  final _todoRepository = TodoRepository();
  final _todoController = StreamController<List<Todo>>.broadcast();

  get todos => _todoController.stream;

  TodoBloc() {
    getTodos();
  }

  getTodos({String query}) async {

    _todoController.sink.add(await _todoRepository.getAllTodos(query: query));
  }

  addTodo(Todo todo) async {
    await _todoRepository.insertTodo(todo);
    getTodos();
  }

  updateTodo(Todo todo) async {
    await _todoRepository.updateTodo(todo);
    getTodos();
  }

  deleteTodoById(int id) async {
    _todoRepository.deleteTodoById(id);
    getTodos();
  }

  dispose() {
    _todoController.close();
  }
}

Страница DAO todo_dao.dart 

import 'package:zencartos/database/database.dart';
import 'package:zencartos/models/todo.dart';


class TodoDao {
  final dbProvider = DatabaseProvider.dbProvider;

  Future<int> createTodo(Todo todo) async{
    final db = await dbProvider.database;
    var result = db.insert(todoTABLE, todo.toDatabaseJson());
    return result;
  }

  Future<List<Todo>> getTodos({List<String> columns, String query})
  async{
    final db = await dbProvider.database;

    List<Map<String, dynamic>> result;
    if (query != null){
      if (query.isNotEmpty)
        result = await db.query(todoTABLE, columns: columns, where: 'description LIKE ?', whereArgs: ["%$query%"]);
    } else {
      result = await db.query(todoTABLE, columns: columns);
    }

    List<Todo> todos = result.isNotEmpty
      ? result.map((item)=> Todo.fromDatabaseJson(item)).toList()
        : [];
    return todos;
  }

  //Update Todo record

  Future<int> updateTodo(Todo todo) async{
    final db = await dbProvider.database;

    var result = await db.update(todoTABLE, todo.toDatabaseJson(),
        where: "id = ?", whereArgs: [todo.id]);

    return result;
  }

  //Delete Todo records
  Future<int> deleteTodo(int id) async{
    final db = await dbProvider.database;

    var result = await db.delete(todoTABLE, where: 'id = ?', whereArgs: [id]);

    return result;
  }


}

Страница базы данных database.dart 

import 'dart:io';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';
import 'package:sqflite/sqflite.dart';


final todoTABLE = 'Todo';

class DatabaseProvider {
  static final DatabaseProvider dbProvider = DatabaseProvider();

  Database _database;

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

  createDatabase() async {
    Directory documentsDirectory = await getApplicationDocumentsDirectory();

    String path = join(documentsDirectory.path, "ReactiveTodo");

    var database = await openDatabase(path, version: 1, onCreate: initDB, onUpgrade: onUpgrade);
    return database;
  }

  void onUpgrade(Database database, int oldVersion, int newVersion){
    if (newVersion > oldVersion){}
  }

  void initDB(Database database, int version) async{
    await database.execute("CREATE TABLE $todoTABLE ("
        "id INTEGER PRIMARY KEY, "
        "description TEXT, "
        "is_done INTEGER "
        ")");
  }
}

Страница модели todo.dart 


class Todo{

  int id;
  String description;
  bool isDone = false;


  Todo({this.id, this.description, this.isDone = false});

  factory Todo.fromDatabaseJson(Map<String, dynamic> data) => Todo(
    id: data['data'],
    description: data['description'],

    isDone: data['is_done'] == 0 ? false : true,
  );

  Map<String, dynamic> toDatabaseJson() => {

    "id": this.id,
    "description": this.description,
    "is_done": this.isDone == false ? 0 : 1,
  };
}

Просмотр страницы home_Page2.dart 

import 'package:flutter/services.dart';
import 'package:zencartos/bloc/todo_bloc.dart';
import 'package:zencartos/models/todo.dart';


class HomePage2 extends StatelessWidget {
  HomePage2({Key key, this.title}) : super(key: key);
  final TodoBloc todoBloc = TodoBloc();
  final String title;

  //Allows Todo card to be dismissable horizontally
  final DismissDirection _dismissDirection = DismissDirection.horizontal;

  @override
  Widget build(BuildContext context) {
    SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle.dark.copyWith(
        statusBarColor: Colors.white,
        systemNavigationBarColor: Colors.white,
        systemNavigationBarIconBrightness: Brightness.dark,
        statusBarBrightness: Brightness.dark));
    return Scaffold(
        resizeToAvoidBottomPadding: false,
        body: SafeArea(
            child: Container(
                color: Colors.white,
                padding:
                const EdgeInsets.only(left: 2.0, right: 2.0, bottom: 2.0),
                child: Container(
                  //This is where the magic starts
                    child: getTodosWidget()))),
        bottomNavigationBar: BottomAppBar(
          color: Colors.white,
          child: Container(
            decoration: BoxDecoration(
                border: Border(
                  top: BorderSide(color: Colors.grey, width: 0.3),
                )),
            child: Row(
              mainAxisSize: MainAxisSize.max,
              children: <Widget>[
                IconButton(
                    icon: Icon(
                      Icons.menu,
                      color: Colors.indigoAccent,
                      size: 28,
                    ),
                    onPressed: () {
                      //just re-pull UI for testing purposes
                      todoBloc.getTodos();
                    }),
                Expanded(
                  child: Text(
                    "Todo",
                    style: TextStyle(
                        color: Colors.black,
                        fontWeight: FontWeight.w600,
                        fontFamily: 'RobotoMono',
                        fontStyle: FontStyle.normal,
                        fontSize: 19),
                  ),
                ),
                Wrap(children: <Widget>[
                  IconButton(
                    icon: Icon(
                      Icons.search,
                      size: 28,
                      color: Colors.indigoAccent,
                    ),
                    onPressed: () {
                      _showTodoSearchSheet(context);
                    },
                  ),
                  Padding(
                    padding: EdgeInsets.only(right: 5),
                  )
                ])
              ],
            ),
          ),
        ),
        floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
        floatingActionButton: Padding(
          padding: EdgeInsets.only(bottom: 25),
          child: FloatingActionButton(
            elevation: 5.0,
            onPressed: () {
              _showAddTodoSheet(context);
            },
            backgroundColor: Colors.white,
            child: Icon(
              Icons.add,
              size: 32,
              color: Colors.indigoAccent,
            ),
          ),
        ));
  }

  void _showAddTodoSheet(BuildContext context) {
    final _todoDescriptionFormController = TextEditingController();
    showModalBottomSheet(
        context: context,
        builder: (builder) {
          return new Padding(
            padding: EdgeInsets.only(
                bottom: MediaQuery.of(context).viewInsets.bottom),
            child: new Container(
              color: Colors.transparent,
              child: new Container(
                height: 230,
                decoration: new BoxDecoration(
                    color: Colors.white,
                    borderRadius: new BorderRadius.only(
                        topLeft: const Radius.circular(10.0),
                        topRight: const Radius.circular(10.0))),
                child: Padding(
                  padding: EdgeInsets.only(
                      left: 15, top: 25.0, right: 15, bottom: 30),
                  child: ListView(
                    children: <Widget>[
                      Row(
                        mainAxisSize: MainAxisSize.min,
                        crossAxisAlignment: CrossAxisAlignment.center,
                        children: <Widget>[
                          Expanded(
                            child: TextFormField(
                              controller: _todoDescriptionFormController,
                              textInputAction: TextInputAction.newline,
                              maxLines: 4,
                              style: TextStyle(
                                  fontSize: 21, fontWeight: FontWeight.w400),
                              autofocus: true,
                              decoration: const InputDecoration(
                                  hintText: 'I have to...',
                                  labelText: 'New Todo',
                                  labelStyle: TextStyle(
                                      color: Colors.indigoAccent,
                                      fontWeight: FontWeight.w500)),
                              validator: (String value) {
                                if (value.isEmpty) {
                                  return 'Empty description!';
                                }
                                return value.contains('')
                                    ? 'Do not use the @ char.'
                                    : null;
                              },
                            ),
                          ),
                          Padding(
                            padding: EdgeInsets.only(left: 5, top: 15),
                            child: CircleAvatar(
                              backgroundColor: Colors.indigoAccent,
                              radius: 18,
                              child: IconButton(
                                icon: Icon(
                                  Icons.save,
                                  size: 22,
                                  color: Colors.white,
                                ),
                                onPressed: () {
                                  final newTodo = Todo(
                                      description:
                                      _todoDescriptionFormController
                                          .value.text);
                                  if (newTodo.description.isNotEmpty) {
                                    /*Create new Todo object and make sure
                                    the Todo description is not empty,
                                    because what's the point of saving empty
                                    Todo
                                    */
                                    todoBloc.addTodo(newTodo);

                                    //dismisses the bottomsheet
                                    Navigator.pop(context);
                                  }
                                },
                              ),
                            ),
                          )
                        ],
                      ),
                    ],
                  ),
                ),
              ),
            ),
          );
        });
  }

  void _showTodoSearchSheet(BuildContext context) {
    final _todoSearchDescriptionFormController = TextEditingController();
    showModalBottomSheet(
        context: context,
        builder: (builder) {
          return new Padding(
            padding: EdgeInsets.only(
                bottom: MediaQuery.of(context).viewInsets.bottom),
            child: new Container(
              color: Colors.transparent,
              child: new Container(
                height: 230,
                decoration: new BoxDecoration(
                    color: Colors.white,
                    borderRadius: new BorderRadius.only(
                        topLeft: const Radius.circular(10.0),
                        topRight: const Radius.circular(10.0))),
                child: Padding(
                  padding: EdgeInsets.only(
                      left: 15, top: 25.0, right: 15, bottom: 30),
                  child: ListView(
                    children: <Widget>[
                      Row(
                        mainAxisSize: MainAxisSize.min,
                        crossAxisAlignment: CrossAxisAlignment.center,
                        children: <Widget>[
                          Expanded(
                            child: TextFormField(
                              controller: _todoSearchDescriptionFormController,
                              textInputAction: TextInputAction.newline,
                              maxLines: 4,
                              style: TextStyle(
                                  fontSize: 18, fontWeight: FontWeight.w400),
                              autofocus: true,
                              decoration: const InputDecoration(
                                hintText: 'Search for todo...',
                                labelText: 'Search *',
                                labelStyle: TextStyle(
                                    color: Colors.indigoAccent,
                                    fontWeight: FontWeight.w500),
                              ),
                              validator: (String value) {
                                return value.contains('@')
                                    ? 'Do not use the @ char.'
                                    : null;
                              },
                            ),
                          ),
                          Padding(
                            padding: EdgeInsets.only(left: 5, top: 15),
                            child: CircleAvatar(
                              backgroundColor: Colors.indigoAccent,
                              radius: 18,
                              child: IconButton(
                                icon: Icon(
                                  Icons.search,
                                  size: 22,
                                  color: Colors.white,
                                ),
                                onPressed: () {
                                  /*This will get all todos
                                  that contains similar string
                                  in the textform
                                  */
                                  todoBloc.getTodos(
                                      query:
                                      _todoSearchDescriptionFormController
                                          .value.text);
                                  //dismisses the bottomsheet
                                  Navigator.pop(context);
                                },
                              ),
                            ),
                          )
                        ],
                      ),
                    ],
                  ),
                ),
              ),
            ),
          );
        });
  }

  Widget getTodosWidget() {
    return StreamBuilder(
      stream: todoBloc.todos,
      builder: (BuildContext context, AsyncSnapshot<List<Todo>> snapshot) {
        return getTodoCardWidget(snapshot);
      },
    );
  }

  Widget getTodoCardWidget(AsyncSnapshot<List<Todo>> snapshot) {
    if (snapshot.hasData) {
      return snapshot.data.length != 0
          ? ListView.builder(
        itemCount: snapshot.data.length,
        itemBuilder: (context, itemPosition) {
          Todo todo = snapshot.data[itemPosition];
          final Widget dismissibleCard = new Dismissible(
            background: Container(
              child: Padding(
                padding: EdgeInsets.only(left: 10),
                child: Align(
                  alignment: Alignment.centerLeft,
                  child: Text(
                    "Deleting",
                    style: TextStyle(color: Colors.white),
                  ),
                ),
              ),
              color: Colors.redAccent,
            ),
            onDismissed: (direction) {
              todoBloc.deleteTodoById(todo.id);
            },
            direction: _dismissDirection,
            key: new ObjectKey(todo),
            child: Card(
                shape: RoundedRectangleBorder(
                  side: BorderSide(color: Colors.grey[200], width: 0.5),
                  borderRadius: BorderRadius.circular(5),
                ),
                color: Colors.white,
                child: ListTile(
                  leading: InkWell(
                    onTap: () {
                      //Reverse the value
                      todo.isDone = !todo.isDone;
                      todoBloc.updateTodo(todo);
                    },
                    child: Container(
                      //decoration: BoxDecoration(),
                      child: Padding(
                        padding: const EdgeInsets.all(15.0),
                        child: todo.isDone
                            ? Icon(
                          Icons.done,
                          size: 26.0,
                          color: Colors.indigoAccent,
                        )
                            : Icon(
                          Icons.check_box_outline_blank,
                          size: 26.0,
                          color: Colors.tealAccent,
                        ),
                      ),
                    ),
                  ),
                  title: Text(
                    todo.description,
                    style: TextStyle(
                        fontSize: 16.5,
                        fontFamily: 'RobotoMono',
                        fontWeight: FontWeight.w500,
                        decoration: todo.isDone
                            ? TextDecoration.lineThrough
                            : TextDecoration.none),
                  ),
                )),
          );
          return dismissibleCard;
        },
      )
          : Container(
          child: Center(
            //this is used whenever there 0 Todo
            //in the data base
            child: noTodoMessageWidget(),
          ));
    } else {
      return Center(
        child: loadingData(),
      );
    }
  }

  Widget loadingData() {
    todoBloc.getTodos();
    return Container(
      child: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            CircularProgressIndicator(),
            Text("Loading...",
                style: TextStyle(fontSize: 19, fontWeight: FontWeight.w500))
          ],
        ),
      ),
    );
  }

  Widget noTodoMessageWidget() {
    return Container(
      child: Text(
        "Start adding Todo...",
        style: TextStyle(fontSize: 19, fontWeight: FontWeight.w500),
      ),
    );
  }

  dispose() {
    todoBloc.dispose();
  }
}

Страница хранилища todo_repository.dart 

import 'package:zencartos/models/todo.dart';

class TodoRepository {
  final todoDao = TodoDao();

  Future getAllTodos({String query}) => todoDao.getTodos(query: query);

  Future insertTodo(Todo todo) => todoDao.createTodo(todo);

  Future updateTodo(Todo todo) => todoDao.updateTodo(todo);

  Future deleteTodoById(int id) => todoDao.deleteTodo(id);

  //We are not going to use this in the demo
  //Future deleteAllTodos() => todoDao.deleteAllTodos();
}

1 Ответ

0 голосов
/ 10 февраля 2020

В вашем todo_bloc.dart ваш метод удаления должен быть: 

deleteTodoById(int id) async {
  await _todoRepository.deleteTodoById(id);
  getTodos();
}
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