如何在SQLITE数据库中创建编辑函数

Question

我创建了一个应用程序，公司可以在其中添加客户的联系方式。数据保存在sqlite上。它与做应用非常相似。在ListTile上，您将获得一个位置图标（尚未功能性），该公司的名称，然后是删除图标（效果很好）。添加按钮正常工作，所有新公司都列出了，并列出了公司的详细信息。

单击公司名称打开瓷砖后，您会看到所有公司的详细信息，但是，在底部，我有一个编辑图标。我似乎找不到我的编辑功能工作。

我找到了一些帮助代码，但是它不起作用，而且由于我对编程的新手，所以我只是不明白我在做什么错。当我单击编辑图标时，它将打开输入页面，其中通常会插入新的详细信息（请参见下文）。它应该做的是打开输入页面，但使用现有的公司详细信息，以便可以进行编辑。

这是我的代码：

我将我的SQFILTE代码保留在我的A库页面：

library

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

 //Customer

 class Todo {
 int? id;
 final String title;
 final String name;
 final String phone;
 final String fax;
 final String email;
 final String street;
 final String city;
 final String town;
 final String code;
 bool isExpanded;

 Todo({
 this.id,
  required this.title,
  required this.name,
  required this.phone,
  required this.fax,
  required this.email,
  required this.street,
  required this.city,
  required this.town,
  required this.code,
  this.isExpanded = false,
  });

 Map<String, dynamic> toMap() {
 return {
  'id': id,
  'title': title,
  'name': name,
  'phone': phone,
  'fax': fax,
  'email': email,
  'street': street,
  'city': city,
  'town': town,
  'code': code,
  'isExpanded': isExpanded ? 1 : 0,
   };
   }

   @override
   String toString() {
   return 'Todo(id : $id, title : $title, name : $name, phone : $phone, fax: $fax, email: 
   $email, street: $street, city: $city, town: $town, code: $code, isExpanded : 
   $isExpanded,)';
   }
   }




    class DatabaseConnect {
    Database? _database;  
    Future<Database> get database async {    
   final dbpath = await getDatabasesPath();   
   const dbname = 'todo.db';   
   final path = join(dbpath, dbname);   
   _database = await openDatabase(path, version: 1, onCreate: _createDB);

   return _database!;
    }


   Future<void> _createDB(Database db, int version) async {
   await db.execute('''
   CREATE TABLE todo(
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    title TEXT,
    name TEXT,
    phone TEXT,
    fax TEXT,
    email TEXT,
    street TEXT,
    city TEXT,
    town TEXT,
    code TEXT,
    isExpanded INTEGER
  
      )
     ''');
   }


   Future<void> insertTodo(Todo todo) async {   
    final db = await database;   
    await db.insert(
    'todo',
    todo.toMap(),
    conflictAlgorithm: ConflictAlgorithm.replace,
    );
    }

  Future<void> deleteTodo(Todo todo) async {
   final db = await database;
   await db.delete(
  'todo',
  where: 'id == ?',
  whereArgs: [todo.id],
  );
   }

   Future<void> updateTodo(Todo todo) async {
   final db = await database;
   db.update('todo', todo.toMap(), where: 'id=?', whereArgs: [todo.id]);

  }



   Future<List<Todo>> getTodo() async {
   final db = await database;


   List<Map<String, dynamic>> items = await db.query(
  'todo',
  orderBy: 'title ASC',
   ); //this will order the list by id in descending order

  return List.generate(
  items.length,
  (i) => Todo(
    id: items[i]['id'],
    title: items[i]['title'],
    name: items[i]['name'],
    phone: items[i]['phone'],
    fax: items[i]['fax'],
    email: items[i]['email'],
    street: items[i]['street'],
    city: items[i]['city'],
    town: items[i]['town'],
    code: items[i]['code'],
    isExpanded: items[i]['isExpanded'] == 1 ? true : false,
    ),
   );
   }

  Future<List<Todo>> searchContacts(String keyword) async {
  final db = await database;
  List<Map<String, dynamic>> items =
    await db.query('todo', where: 'title LIKE ?', whereArgs: ['$keyword%']);

   return List.generate(
   items.length,
   (i) => Todo(
    id: items[i]['id'],
    title: items[i]['title'],
    name: items[i]['name'],
    phone: items[i]['phone'],
    fax: items[i]['fax'],
    email: items[i]['email'],
    street: items[i]['street'],
    city: items[i]['city'],
    town: items[i]['town'],
    code: items[i]['code'],
    isExpanded: items[i]['isExpanded'] == 1 ? true : false,
    ),
    );
    }
    }

然后，在下面的代码上（casturecercard）在哪里所有新公司数据的ListTile都将转换为卡。在这里还可以看到编辑图标，该图标将被压制到编辑页面。我现在在这里遇到错误，因为我不知道使用“ UpdateFunction”在此处插入什么代码。

customercard ，

 import 'package:flutter/material.dart';
 import 'library.dart';
 import 'package:test_sqlite/editpage.dart';

 class CustomerCard extends StatefulWidget {
 final int id;
 final String title;
 final String name;
 final String phone;
 final String fax;
 final String email;
 final String street;
 final String city;
  final String town;
  final String code;
  bool isExpanded;
  final Function insertFunction;
  final Function deleteFunction;
  final Function updateFunction;

  CustomerCard(
  {required this.id,
  required this.title,
  required this.name,
  required this.phone,
  required this.fax,
  required this.email,
  required this.street,
  required this.city,
  required this.town,
  required this.code,
  required this.isExpanded,
  required this.insertFunction,
  required this.deleteFunction,
   required this.updateFunction,
  Key? key})
  : super(key: key);

  @override
  _CustomerCardState createState() => _CustomerCardState();
   }

  class _CustomerCardState extends State<CustomerCard> {
  var db = DatabaseConnect();

  @override
  Widget build(BuildContext context) {
  var anotherTodo = Todo(
    id: widget.id,
    title: widget.title,
    name: widget.name,
    phone: widget.phone,
    fax: widget.fax,
    email: widget.email,
    street: widget.street,
    city: widget.city,
    town: widget.town,
    code: widget.code,
    isExpanded: widget.isExpanded);

   return Card(
    child: Column(
    crossAxisAlignment: CrossAxisAlignment.start,
    children: [
      Theme(
        data: Theme.of(context).copyWith(dividerColor: Colors.transparent),
        child: ExpansionTile(
          initiallyExpanded: false,
          title: Text(
            widget.title,
            style: const TextStyle(
              //fontWeight: FontWeight.bold,
              fontSize: 16,
            ),
          ),
          children: [
            ListTile(
              leading: const Icon(
                Icons.person,
                size: 20,
                color: Colors.teal,
              ),
              visualDensity: const VisualDensity(vertical: -3),
              title: Text(
                widget.name,
                style: const TextStyle(
                  fontSize: 16,
                  fontWeight: FontWeight.normal,
                  color: Colors.black,
                ),
              ),
            ),
            ListTile(
              leading: const Icon(
                Icons.phone,
                size: 20,
                color: Colors.teal,
              ),
              visualDensity: const VisualDensity(vertical: -4),
              title: Text(
                widget.phone,
                style: const TextStyle(
                  fontSize: 16,
                  fontWeight: FontWeight.normal,
                  color: Colors.black,
                ),
              ),
            ),
            ListTile(
              leading: const Icon(
                Icons.report,
                size: 20,
                color: Colors.teal,
              ),
              visualDensity: const VisualDensity(vertical: -4),
              title: Text(
                widget.fax,
                style: const TextStyle(
                  fontSize: 16,
                  fontWeight: FontWeight.normal,
                  color: Colors.black,
                ),
              ),
            ),
            ListTile(
              leading: const Icon(
                Icons.email,
                size: 20,
                color: Colors.teal,
              ),
              visualDensity: const VisualDensity(vertical: -4),
              title: Text(
                widget.email,
                style: const TextStyle(
                  fontSize: 16,
                  fontWeight: FontWeight.normal,
                  color: Colors.black,
                ),
              ),
            ),
            ListTile(
              leading: const Icon(
                Icons.place,
                size: 20,
                color: Colors.teal,
              ),
              visualDensity: const VisualDensity(vertical: -4),
              title: Text(
                widget.street,
                style: const TextStyle(
                  fontSize: 16,
                  fontWeight: FontWeight.normal,
                  color: Colors.black,
                ),
              ),
            ),
            ListTile(
              leading: const Icon(
                Icons.place,
                size: 20,
                color: Colors.teal,
              ),
              visualDensity: const VisualDensity(vertical: -4),
              title: Text(
                widget.city,
                style: const TextStyle(
                  fontSize: 16,
                  fontWeight: FontWeight.normal,
                  color: Colors.black,
                ),
              ),
            ),
            ListTile(
              leading: const Icon(
                Icons.place,
                size: 20,
                color: Colors.teal,
              ),
              visualDensity: const VisualDensity(vertical: -4),
              title: Text(
                widget.town,
                style: const TextStyle(
                  fontSize: 16,
                  fontWeight: FontWeight.normal,
                  color: Colors.black,
                ),
              ),
            ),
            ListTile(
              leading: const Icon(
                Icons.code,
                size: 20,
                color: Colors.teal,
              ),
              visualDensity: const VisualDensity(vertical: -4),
              title: Text(
                widget.code,
                style: const TextStyle(
                  fontSize: 16,
                  fontWeight: FontWeight.normal,
                  color: Colors.black,
                ),
              ),
            ),
            Row(
              mainAxisAlignment: MainAxisAlignment.end,
              children: [
                Padding(
                  padding: const EdgeInsets.all(8.0),
                  child: ElevatedButton(
                    onPressed: () {
                      showModalBottomSheet(
                        isScrollControlled: true,
                        context: context,
                        builder: (context) =>
                            EditPage(updateFunction: addItem),);
                    },
                    style: ElevatedButton.styleFrom(
                      shape: const StadiumBorder(),
                      primary: Colors.white,
                      elevation: 0,
                      padding: const EdgeInsets.symmetric(
                          horizontal: 2, vertical: 2),
                    ),
                    child: const Icon(
                      Icons.edit,
                      size: 20,
                      color: Colors.grey,
                    ),
                  ),
                ),
              ],
            ),
          ],
          leading: const IconButton(
            icon: Icon(
              Icons.place,
              color: Colors.blue,
              size: 20,
            ),
            onPressed: null,
            alignment: Alignment.center,
          ),
          trailing: IconButton(
            onPressed: () {
              widget.deleteFunction(anotherTodo);
            },
            icon: const Icon(
              Icons.delete,
              color: Colors.red,
              size: 20,
            ),

然后编辑页面是输入页面时，在按下编辑按钮时将转到该页面。在此页面上，应该查看所有现有的公司数据，以便可以对其进行编辑，但是它仅打开带有提示文本的新输入页面。

editPage

import 'package:flutter/material.dart';
import 'library.dart';
import 'package:flutter/cupertino.dart';

class EditPage extends StatelessWidget {

final textController = TextEditingController();
final nameController = TextEditingController();
final phoneController = TextEditingController();
final faxController = TextEditingController();
final emailController = TextEditingController();
final streetController = TextEditingController();
final cityController = TextEditingController();
final townController = TextEditingController();
final codeController = TextEditingController();

final Function updateFunction;

 // DatabaseConnect updateFunction = DatabaseConnect();

 EditPage({required this.updateFunction, Key? key, todo}) : super(key: key);

 @override
 Widget build(BuildContext context) {
 return Container(
  padding: const EdgeInsets.all(30.0),
  decoration: const BoxDecoration(
    color: Colors.white,
    borderRadius: BorderRadius.only(
      topLeft: Radius.circular(30.0),
      topRight: Radius.circular(30.0),
    ),
    ),
    child: Scaffold(
     appBar: AppBar(
      backgroundColor: Colors.white,
      elevation: 0,
      title: const Padding(
        padding: EdgeInsets.all(15.0),
        child: Text(
          'Client Details',
          style: TextStyle(color: Colors.black, fontSize: 24),
        ),
      ),
      leading: GestureDetector(
        onTap: () {
          Navigator.of(context).pushReplacementNamed('/homePage');
        },
        child: const Icon(
          Icons.arrow_back,
          color: Colors.black,
        ),
        ),
      ),
      body: SingleChildScrollView(
       child: Container(
        color: Colors.white,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            
              TextField(
              controller: textController,
              autofocus: true,
              textAlign: TextAlign.left,
              decoration: const InputDecoration(
                hintText: ' Company Name',
                hintStyle: TextStyle(color: Colors.grey),
              ),
             ),
            TextField(
              controller: nameController,
              autofocus: true,
              textAlign: TextAlign.left,
              decoration: const InputDecoration(
                hintText: ' Contact Name & Surname',
                hintStyle: TextStyle(color: Colors.grey),
              ),
            ),
            TextField(
              controller: phoneController,
              autofocus: true,
              textAlign: TextAlign.left,
              decoration: const InputDecoration(
                hintText: ' Contact Number',
                hintStyle: TextStyle(color: Colors.grey),
              ),
            ),
            TextField(
              controller: faxController,
              autofocus: true,
              textAlign: TextAlign.left,
              decoration: const InputDecoration(
                hintText: 'Fax Number',
                hintStyle: TextStyle(color: Colors.grey),
              ),
            ),
            TextField(
              controller: emailController,
              autofocus: true,
              textAlign: TextAlign.left,
              decoration: const InputDecoration(
                hintText: 'Email Address',
                hintStyle: TextStyle(color: Colors.grey),
              ),
            ),
            TextField(
              controller: streetController,
              autofocus: true,
              textAlign: TextAlign.left,
              decoration: const InputDecoration(
                hintText: 'Street Name',
                hintStyle: TextStyle(color: Colors.grey),
              ),
            ),
            TextField(
              controller: cityController,
              autofocus: true,
              textAlign: TextAlign.left,
              decoration: const InputDecoration(
                hintText: ' City',
                hintStyle: TextStyle(color: Colors.grey),
              ),
            ),
            TextField(
              controller: townController,
              autofocus: true,
              textAlign: TextAlign.left,
              decoration: const InputDecoration(
                hintText: 'Town',
                hintStyle: TextStyle(color: Colors.grey),
              ),
            ),
            TextField(
              controller: codeController,
              autofocus: true,
              textAlign: TextAlign.left,
              decoration: const InputDecoration(
                hintText: ' Code',
                hintStyle: TextStyle(color: Colors.grey),
              ),
            ),
            GestureDetector(
              onTap: () {
                Navigator.pop(context);
                var myTodo = Todo(
                    title: textController.text,
                    name: nameController.text,
                    phone: phoneController.text,
                    fax: faxController.text,
                    email: emailController.text,
                    street: streetController.text,
                    city: cityController.text,
                    town: townController.text,
                    code: codeController.text,
                    isExpanded: false);
                updateFunction.updateTodo(myTodo);
              },
              child: Padding(
                padding: const EdgeInsets.fromLTRB(0, 10, 0, 0),
                child: Container(
                  decoration: BoxDecoration(
                    color: Theme.of(context).primaryColor,
                    borderRadius: BorderRadius.circular(15),
                  ),
                  padding: const EdgeInsets.symmetric(
                      horizontal: 25, vertical: 10),
                  child: const Text(
                    'Add',
                    textAlign: TextAlign.center,
                    style: TextStyle(
                      color: Colors.white,
                      fontWeight: FontWeight.bold,
                    ),
          

然后，我有一个客户页面，您将在其中看到以下功能：addItem，deleteItem和updateEtem，本质上包含在'insertfunction，deletefunction和updateFunction中。

客户

import 'package:flutter/material.dart';
import 'package:flutter/cupertino.dart';
import '../customerlist.dart';
import '../library.dart';
import '../user_input.dart';

class Customer extends StatefulWidget {
const Customer({Key? key}) : super(key: key);

 @override
  _CustomerState createState() => _CustomerState();
  }

  class _CustomerState extends State<Customer> {
   var db = DatabaseConnect();

  void addItem(Todo todo) async {
  await db.insertTodo(todo);
  setState(() {});
  }

   void deleteItem(Todo todo) async {
    await db.deleteTodo(todo);
    setState(() {});
    }

    void updateItem(Todo todo) async {
    await db.updateTodo(todo);
    setState(() {});
    }

    @override
     Widget build(BuildContext context) {
     return Scaffold(
      backgroundColor: Colors.white,
     appBar: AppBar(
      centerTitle: false,
      title: const Padding(
        padding: EdgeInsets.all(50.0),
        child: Text(
          'My Clients',
          style: TextStyle(
              fontSize: 24,
              fontWeight: FontWeight.w600,
              color: Colors.black),
        ),
      ),
      backgroundColor: Colors.white,
      elevation: 0,
      actions: [
        IconButton(
          onPressed: () {
            Navigator.of(context).pushReplacementNamed('/searchPage');
          },
          icon: const Icon(
            Icons.search,
            color: Colors.black,
          ),
        ),
        ]),
        body: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
       const Padding(
        padding: EdgeInsets.symmetric(horizontal: 16, vertical: 10),
        child: Text(
          'Company Name',
          style: TextStyle(fontSize: 14, fontWeight: FontWeight.w600),
        ),
        ),
        CustomerList(
         insertFunction: addItem,
          deleteFunction: deleteItem,
         updateFunction: updateItem,
        ),
        ],

    
        ),
       floatingActionButton: FloatingActionButton(
        backgroundColor: Colors.lightBlueAccent,
        child: const Icon(Icons.add),
        onPressed: () {
         showModalBottomSheet(
          isScrollControlled: true,
          context: context,
          builder: (context) => CustomerProfile(insertFunction: addItem),
          );
        }

ps：我真的需要帮助。我已经被困在这里一个多月了。我已经观看了YouTube频道，阅读堆栈溢出和文档，但我根本无法弄清楚。任何帮助真的将不胜感激。

Answer 1

从您的问题中，我能够理解的是，基本上，您要与当前数据一起填充编辑页面屏幕，然后允许用户对其进行修改（应该如此）。

在CustomerCard屏幕中，您有数据，并且希望能够对其进行修改。最简单的解决方案，我可以看到，只需将此数据传递给您的编辑页面窗口小部件即可。

class EditPage extends StatelessWidget {

final Todo todo; // <- Add this variable

final late TextEditingController textController; // Do this to add initial value to controller  
final late TextEditingController nameController;
// ...  and the rest of the TextEditingControllers

EditPage({required this.updateFunction, Key? key, 
    required this.todo // <- Add this
}) : super(key: key);

@override
void initState() {
    textController = TextEditingController(text: todo.title);
    nameController = TextEditingController(text: todo.name);
    // .. and add the rest of the fields

    super.initState();
}

@override
Widget build(BuildContext context) {
   ...
}

当您调用编辑页面时，您只需将todo传递给它即可。您可以做到这一点：

EditPage(
    updateFunction: addItem,
    todo: anotherTodo, // This is the todo you are creating in the customerCard
)

这将使您的当前数据填充到编辑页面。然后，您可以调用您的更新方法，以使用新值更新此数据。要获取新值，请在文本字段上添加on Changed函数。

另外，您在编辑页面中有一个错误：

GestureDetector(
          onTap: () {
           // Navigator.pop(context); // <- This should be called at the end
            var myTodo = Todo(
                title: textController.text,
                name: nameController.text,
                phone: phoneController.text,
                fax: faxController.text,
                email: emailController.text,
                street: streetController.text,
                city: cityController.text,
                town: townController.text,
                code: codeController.text,
                isExpanded: false);
            updateFunction.updateTodo(myTodo);
            
            Navigator.pop(context); // <- Here
          },

希望这会有所帮助。

Answer 2

我最终设法解决了这个问题。

我的UpdateFunction和UpdateItem功能实际上一直很好地工作。我意识到我从未将“ ID”分配给我的变量“ UpdateTodo”。我只有我的textedingcontroller。现在，在我的SQL数据库中，数据库使用“ Where：ID”进行更新，但是由于我没有为文本分配“ ID”，因此每次更新时，我都会有效地返回null。

这是修复之前的getRuedEtector代码的片段，

GestureDetector(
          onTap: () {
            Navigator.pop(context);
            var updateTodo = Todo(
                
                title: textController.text,
                name: nameController.text,
                phone: phoneController.text,
                fax: faxController.text,
                email: emailController.text,
                street: streetController.text,
                city: cityController.text,
                town: townController.text,
                code: codeController.text,
                isExpanded: false);
            nalaFunction(updateTodo);
          },

在修复程序之后，在这里使用相同的代码：

GestureDetector(
          onTap: () {
            Navigator.pop(context);
            var updateTodo = Todo(
                 id: id,
                title: textController.text,
                name: nameController.text,
                phone: phoneController.text,
                fax: faxController.text,
                email: emailController.text,
                street: streetController.text,
                city: cityController.text,
                town: townController.text,
                code: codeController.text,
                isExpanded: false);
            nalaFunction(updateTodo);
          },

以及在customercard类中传递'id'的代码，直到编辑页面：

class CustomerCard extends StatefulWidget {
 final int id;
 final String title;
 final String name;
 final String phone;
 final String fax;
 final String email;
 final String street;
 final String city;
 final String town;
 final String code;
 bool isExpanded;

final Function janFunction;
final Function simbaFunction;

CustomerCard(
 {required this.id,
 required this.title,
 required this.name,
 required this.phone,
 required this.fax,
 required this.email,
 required this.street,
 required this.city,
 required this.town,
 required this.code,
 required this.isExpanded,

和..

 Row(mainAxisAlignment: MainAxisAlignment.end,
  children: [
  Padding(
  padding: const EdgeInsets.all(8.0),
   child: ElevatedButton(
     onPressed: () {
     showModalBottomSheet(
     isScrollControlled: true,
     context: context,
     builder: (context) => EditPage(
      nalaFunction: widget.simbaFunction,
      variable: anotherTodo,
      id: widget.id,
      ),

                    //updateFunction,
                    //),
                  );
                },

并将“ id”传递到编辑页面以便在同一页面上的GestureDetector可以将其与之联系：

class EditPage extends StatelessWidget {
 final Todo variable;
 final Function nalaFunction;
 final int id;

 late final textController = TextEditingController(text: variable.title);
 late final nameController = TextEditingController(text: variable.name);
 late final phoneController = TextEditingController(text: variable.phone);
 late final faxController = TextEditingController(text: variable.fax);
 late final emailController = TextEditingController(text: variable.email);
 late final streetController = TextEditingController(text: variable.street);
 late final cityController = TextEditingController(text: variable.city);
 late final townController = TextEditingController(text: variable.town);
 late final codeController = TextEditingController(text: variable.code);

 EditPage({Key? key,
 required this.nalaFunction,
 required this.variable,
 required this.id,
 }) : super(key: key);

这解决了我的问题，现在我的应用程序现在可以完美更新新的客户数据。