我正在开发一个简单的Todolist应用。我创建了一个数据库，用于将数据存储在文件“ to_do_item.dart”下。文件“ database_helper.dart”是我存储所有CRUD函数的位置。
打开应用程序后，用户将看到在文件“ todo_list.dart”下创建的屏幕，其中已添加的任务将在列表视图中显示。当用户单击操作按钮时，它将把它们发送到“ input_screen.dart”，其中有一个文本字段可输入任务。用户单击屏幕键盘上的“完成”后，数据将保存在一个名为“ Itemlist”的列表中（“ input_screen”的第49行）。
我想将此列表发送到“ todo_list.dart”并在可滚动的列表视图中显示它们，但我不确定要使用哪种方法。目前，我只想添加并显示该项目。
尝试使用getters，但无法将其用于另一个类，并尝试搜索flutter上其他todolist应用的制作方式，但它们在同一类上使用AlertDialog；我想从一个屏幕（InputScreen类）上获取输入，并在另一个屏幕（TodoList类）上显示它。
“ todo_list.dart”下的代码-
services.AddSingleton<AntiForgery>();
services.AddHttpContextAccessor();
“ input_screen.dart”下的代码
Container(
color: Colors.white,
alignment: Alignment.topLeft,
margin: const EdgeInsets.all(20),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
SizedBox(height: 110,),
Text( "tasks for today",),
SizedBox(height: 20,),
//Todo: display listview on below column
// Column(
// children: <Widget>[
// new Flexible(child: ListView.builder(
itemBuilder:(_,intindex){
// return ListTile(
//// title: _itema,
// );
// }
// )
// )
// ],
// ),
SizedBox(height: 320,),
Row(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[
FloatingActionButton(
onPressed: (){
Navigator.push(context, MaterialPageRoute(builder: (context) => InputScreen()));
},
heroTag: "btn2",
child: Icon(Icons.add, color: Colors.white,), backgroundColor: Colors.black87,),
],
)
]
),
),
“ to_do_item.dart”下的代码-
class InputScreen extends StatefulWidget {
@override
_InputScreenState createState() => _InputScreenState();
}
class _InputScreenState extends State<InputScreen> {
@override
void initState() {
// TODO: implement initState
super.initState();
_readList();
}
void _handleSubmitted(String text) async{
taskcontroller.clear();
TodoItem obj = new TodoItem(text, DateTime.now().toIso8601String());
int SavedItemId = await db.saveItem(obj);
print("item saved id: $SavedItemId");
print("$text");
TodoItem addedItem = await db.getItem(SavedItemId);
setState(() {
Itemlist.insert(0, addedItem);
});
}
_readList() async{
List items = await db.getItems();
items.forEach((item) {
TodoItem todoItem = TodoItem.map(items);
print("db it4ems: ${todoItem.itemName.toString()}");
});
}
var db = new DatabaseHelper();
final List<TodoItem> Itemlist= <TodoItem>[];
TextEditingController taskcontroller = new TextEditingController();
@override
Widget build(BuildContext context) {
SystemChrome.setEnabledSystemUIOverlays([]);
return Scaffold(
resizeToAvoidBottomPadding: false,
backgroundColor: Colors.white,
body: SingleChildScrollView(
child: Column(
mainAxisAlignment: MainAxisAlignment.start,
// crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Container(
color: Colors.white,
alignment: Alignment.topLeft,
margin: const EdgeInsets.all(20),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
SizedBox(height: 110,),
Text("tasks for today:",),
SizedBox(height: 10,),
//Todo: remove sized box below and display tasks there
TextField(
autofocus: true,
onEditingComplete: (){Navigator.pop(context);},
maxLength: 10,
onSubmitted: (NewValue){ _handleSubmitted(NewValue);},
controller: taskcontroller,
decoration: InputDecoration(
labelText: "enter tasks here"
),
style: TextStyle(height: 1.2, fontSize: 20, color: Colors.black87),
)
]
),
),
],
),
),
);
}
}
“ database_helper.dart”下的代码-
import 'package:flutter/material.dart';
class TodoItem extends StatelessWidget {
String _itemName;
String _dateCreated;
int _id;
TodoItem(this._itemName, this._dateCreated);
TodoItem.map(dynamic obj) {
this._itemName = obj["itemName"];
this._dateCreated = obj["dateCreated"];
this._id = obj["id"];
}
String get itemName => _itemName;
String get dateCreated => _dateCreated;
int get id => _id;
Map<String, dynamic> toMap() {
var map = new Map<String, dynamic>();
map["itemName"] = _itemName;
map["dateCreated"] = _dateCreated;
if (_id != null) {
map["id"] = _id;
}
return map;
}
TodoItem.fromMap(Map<String, dynamic> map) {
this._itemName = map["itemName"];
this._dateCreated = map["dateCreated"];
this._id = map["id"];
}
@override
Widget build(BuildContext context) {
return new Container(
margin: const EdgeInsets.all(8.0),
child: new Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
new Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Text(_itemName, )
],
),
],
),
);
}
}
答案 0 :(得分：0)
这可能是this
的副本尽管如此，我希望这会有所帮助
class FrontPage extends StatefulWidget {
@override
_FrontPageState createState() => _FrontPageState();
}
class _FrontPageState extends State<FrontPage> {
// Activity currentActivity;
var recentActivities = <Widget>[];//<Widget>[Activity("Skiing", "assets/activity_logos/Squat.png").getSummary(),Activity("Skiing", "assets/activity_logos/Squat.png").getSummary(),Activity("Skiing", "assets/activity_logos/Squat.png").getSummary(),Activity("Skiing", "assets/activity_logos/Squat.png").getSummary(),Activity("Skiing", "assets/activity_logos/Squat.png").getSummary(),Activity("Skiing", "assets/activity_logos/Squat.png").getSummary()];
var upcomingActivities = <Widget>[];//<Widget>[Activity("Jog", "assets/activity_logos/Squat.png", status: ActivityStatus.completed,).getSummary()];
List<String> tasks = ["previous1", "previous2"];
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
centerTitle: true,
title: Text('Home'),
actions: <Widget>[
GestureDetector(
child: Align(child:Text("+", style: TextStyle(fontSize: 40)), alignment: Alignment.centerLeft, widthFactor: 2,),
onTap: () => Navigator.pushNamed(context, '/activity/new'),
)
],
),
body: Container(
color: Colors.white,
alignment: Alignment.topLeft,
margin: const EdgeInsets.all(20),
child: Stack(
alignment: Alignment.bottomRight,
children: <Widget>[
Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
SizedBox(height: 110,),
Text( "tasks for today",),
SizedBox(height: 20,),
Expanded(child: ListView.builder(
itemCount: tasks.length,
itemBuilder: (BuildContext context, int index) {
return Text(tasks[index]);
})),
]),
FloatingActionButton(
onPressed: () async {
final result = await Navigator.push(
context,
MaterialPageRoute(
builder: (context) => InputScreen(),
));
setState(() {
tasks.add(result);
});
},
heroTag: "btn2",
child: Icon(Icons.add, color: Colors.white,), backgroundColor: Colors.black87,),
]),
),
);
}
}
class InputScreen extends StatefulWidget {
@override
_InputScreenState createState() => _InputScreenState();
}
class _InputScreenState extends State<InputScreen> {
@override
void initState() {
// TODO: implement initState
super.initState();
// _readList();
}
// final List<TodoItem> Itemlist= <TodoItem>[];
TextEditingController taskcontroller = new TextEditingController();
@override
Widget build(BuildContext context) {
SystemChrome.setEnabledSystemUIOverlays([]);
return Scaffold(
resizeToAvoidBottomPadding: false,
backgroundColor: Colors.white,
body: SingleChildScrollView(
child: Column(
mainAxisAlignment: MainAxisAlignment.start,
// crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Container(
color: Colors.white,
alignment: Alignment.topLeft,
margin: const EdgeInsets.all(20),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
SizedBox(height: 110,),
Text("tasks for today:",),
SizedBox(height: 10,),
//Todo: remove sized box below and display tasks there
TextField(
autofocus: true,
onEditingComplete: () {
String textToSendBack = taskcontroller.text;
Navigator.pop(context, textToSendBack );
},
maxLength: 10,
onSubmitted: (NewValue){ },
controller: taskcontroller,
decoration: InputDecoration(
labelText: "enter tasks here"
),
style: TextStyle(height: 1.2, fontSize: 20, color: Colors.black87),
)
]
),
),
],
),
),
);
}
}
class TodoItem extends StatelessWidget {
String _itemName;
String _dateCreated;
int _id;
TodoItem(this._itemName, this._dateCreated);
TodoItem.map(dynamic obj) {
this._itemName = obj["itemName"];
this._dateCreated = obj["dateCreated"];
this._id = obj["id"];
}
String get itemName => _itemName;
String get dateCreated => _dateCreated;
int get id => _id;
Map<String, dynamic> toMap() {
var map = new Map<String, dynamic>();
map["itemName"] = _itemName;
map["dateCreated"] = _dateCreated;
if (_id != null) {
map["id"] = _id;
}
return map;
}
TodoItem.fromMap(Map<String, dynamic> map) {
this._itemName = map["itemName"];
this._dateCreated = map["dateCreated"];
this._id = map["id"];
}
@override
Widget build(BuildContext context) {
return new Container(
margin: const EdgeInsets.all(8.0),
child: new Row(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
new Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Text(_itemName, )
],
),
],
),
);
}
}
主要更改包括
在输入页面上：
TextField(
autofocus: true,
onEditingComplete: () {
String textToSendBack = taskcontroller.text;
Navigator.pop(context, textToSendBack );
}
在首页上：
FloatingActionButton(
onPressed: () async {
final result = await Navigator.push(
context,
MaterialPageRoute(
builder: (context) => InputScreen(),
));
setState(() {
tasks.add(result);
});
},
一些小部件布局，我将数据保存在一个任务数组中，但是您可以根据需要进行更改。