import 'package:flutter/material.dart';
import '../main.dart';
import 'colors.dart';
import 'todo_item.dart';
import 'todo.dart';
import 'package:shared_preferences/shared_preferences.dart';
class Toodoo extends StatefulWidget {
const Toodoo({Key? key}) : super(key: key);
@override
State<Toodoo> createState() => _ToodooState();
}
class _ToodooState extends State<Toodoo> {
final todosList = ToDo.todoList();
List<ToDo> _foundToDo = [];
final _todoController = TextEditingController();
final GlobalKey<ScaffoldState> _key = GlobalKey();
String ""
@override
void initState() {
_foundToDo = todosList;
super.initState();
}
@override
Widget build(BuildContext context) {
return Scaffold(
key: _key,
appBar: AppBar(
leading: IconButton(
icon: const Icon(Icons.menu, color: Colors.black),
onPressed: () => _key.currentState!.openDrawer(),
),
backgroundColor: const Color(0xff346594),
title: const Text("ToDos", style: TextStyle(color: Colors.black)),
),
backgroundColor: tdBGColor,
body: Stack(
children: [
Container(
padding: const EdgeInsets.symmetric(
horizontal: 20,
vertical: 15,
),
child: Column(
children: [
searchBox(),
Expanded(
child: ListView(
children: [
Container(
margin: const EdgeInsets.only(
top: 50,
bottom: 20,
),
child: const Text(
'All ToDos',
style: TextStyle(
fontSize: 20,
fontWeight: FontWeight.w500,
),
),
),
for (ToDo todo in _foundToDo.reversed)
ToDoItem(
todo: todo,
onToDoChanged: _handleToDoChange,
onDeleteItem: _deleteToDoItem,
),
],
),
)
],
),
),
Align(
alignment: Alignment.bottomCenter,
child: Row(children: [
Expanded(
child: Container(
margin: const EdgeInsets.only(
bottom: 20,
right: 20,
left: 20,
),
padding: const EdgeInsets.symmetric(
horizontal: 20,
vertical: 5,
),
decoration: BoxDecoration(
color: Colors.white,
boxShadow: const [
BoxShadow(
color: Colors.grey,
offset: Offset(0.0, 0.0),
blurRadius: 10.0,
spreadRadius: 0.0,
),
],
borderRadius: BorderRadius.circular(10),
),
child: TextField(
controller: _todoController,
decoration: const InputDecoration(
hintText: 'Add a new todo item',
border: InputBorder.none),
),
),
),
Container(
margin: const EdgeInsets.only(
bottom: 20,
right: 20,
),
child: ElevatedButton(
onPressed: () {
_addToDoItem(_todoController.text);
},
style: ElevatedButton.styleFrom(
backgroundColor: tdBlue,
minimumSize: const Size(60, 60),
elevation: 10,
),
child: const Text('+', style: TextStyle(fontSize: 40),),
),
),
]),
),
],
),
drawer: const Navigation(),
);
}
void _handleToDoChange(ToDo todo) {
setState(() {
todo.isDone = !todo.isDone;
});
}
void _deleteToDoItem(String id) {
setState(() {
todosList.removeWhere((item) => item.id == id);
});
}
void _addToDoItem(String toDo) async{
final sp = await SharedPreferences.getInstance();
setState(() {
todosList.add(ToDo(
id: DateTime.now().millisecondsSinceEpoch.toString(),
todoText: toDo,
));
});
sp.setString(id, todo)
_todoController.clear();
}
void _runFilter(String enteredKeyword) {
List<ToDo> results = [];
if (enteredKeyword.isEmpty) {
results = todosList;
} else {
results = todosList
.where((item) => item.todoText!
.toLowerCase()
.contains(enteredKeyword.toLowerCase()))
.toList();
}
setState(() {
_foundToDo = results;
});
}
Widget searchBox() {
return Container(
);
}
}
我正在尝试使用共享首选项在本地保存待办事项数据，但不知道如何实现这一点，对此的任何帮助将不胜感激。共享首选项是在此类应用程序中使用的最佳选择，因此这就是我使用共享首选项的原因偏好而不是 firebase。
我将来已经初始化了共享首选项，但问题是如何使用代码上面给出的控制器读取和显示数据。
是的，共享首选项是将数据永久存储在本地设备上的好方法。我可以建议你一种方法来做到这一点。
您只需要创建一个键（和值），并且该值将是一个字符串化数组。每次用户创建新的待办事项时，您首先需要拉取之前的数组，将其解析为 JSON，将最新的待办事项推送到该数组中，然后再次设置键值。
如果您想通过仅从一个键提取数据来向用户显示所有待办事项，此数组也会帮助您，因为所有待办事项将存储在一个数组中。
var todos = [
{
"id": "",
"todoText": "''"
},
{
"id": "",
"todoText": "''"
},
...
]
但是您需要存储字符串化数组，因此从共享首选项获取数据后需要解析回 JSON
处理小数据时，共享偏好是一个好主意。示例：
// NB: you need to have shared_preferences in your packages (pubspec.yaml)
class SharedPreferencesFunction{
// save String, example: 'John', 'I love coding, it is fun' and so on
void saveString({required String key, required String value}) async {
final SharedPreferences sharedPreferences =
await SharedPreferences.getInstance();
await sharedPreferences.setString(key, value);
}
// save bool example: true, or false
void saveBool({required String key, required bool value}) async {
final SharedPreferences sharedPreferences =
await SharedPreferences.getInstance();
await sharedPreferences.setBool(key, value);
}
// save int, numbers without points. like 1,50, 100 not 0.9, or
//zero point other something(number)
void saveInt({required String key, required int value}) async {
final SharedPreferences sharedPreferences =
await SharedPreferences.getInstance();
await sharedPreferences.setInt(key, value);
}
// save double, number with decimal point. like 9.0, 10.5, e.t.c
void saveDouble({required String key, required double value}) async {
final SharedPreferences sharedPreferences =
await SharedPreferences.getInstance();
await sharedPreferences.setDouble(key, value);
}
// save List<String> a list of Strings. more like ['paul', 'john', 'jack'];
void saveListOfString({
required String key,
required List<String> value,
}) async {
final SharedPreferences sharedPreferences =
await SharedPreferences.getInstance();
await sharedPreferences.setStringList(key, value);
}
}
Now to retrieve save this data you need to simply call that above method
like this:
class MyClass {
// your other codes,
void saveString(String someValue){
SharedPreferencesFunction().saveString(key:'learning', value: someValue);
}
// and others like that, according your data. // bool, int, double,
// List<String>, .... and so on
// remember to use this code according to your data type needs, but your data // has to be (bool, String, int, double,List<String>) if you happen to have a // map and you want to save it, don't try to use the following code
final Map<String, Object> info = {
'name':'john',
'age':'20',
};
// error
final String data = info.toString();
// and save it like
saveString(data); // it is possible to save this data but you won't be able // to retrieve it for use later.
// instead use import 'dart:convert' show json;
like
final String data = json.encode(info);
// retrieve using json.decode
}
// finally retrieving data is simple
class RetrieveData{
void data()async{
final sharedPref= await SharedPreferences.getInstance();
sharedPref.getString('learning');
// this returns a String ? might be null if the value is absent
}
}