我有一个模型类，我曾经用它从主要的有状态类中创建一个对象。我的主类有一个文本框和一个按钮。但是他们都是完全不同的有状态类(Class)。也就是说，我在dart文件中有3个不同的类(主页，文本字段，按钮)。我想在我的文本字段和按钮中访问和修改在主页构建中启动的对象。
我的工作:我已将我的对象放在dart文件中所有类的顶部，并假定所有类都可以访问它们。那是成功的。所有类都可以访问该对象，即使从主页面向该对象初始化的值也可以在其他类(文本字段，按钮)中使用。
现在遇到的问题是:即使我可以访问对象中的那些值，但无论FancyTextField类是否更新，我都无法将其修改为StatusButton类的最新值。
我的项目做什么:我将从主页构建中的firestore数据库中获取一些值，并将其传递给其他两个类中的textfield和button。这样，它就类似于我在其上的值。然后，我将从文本字段和按钮将修改后的值保存到对象，然后将其从主页上传到Firestore数据库。
页面的完整代码:
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:flutter/painting.dart';
import 'package:flutter/services.dart';
import 'package:om/models/machine.dart';
import 'package:om/utils/kalaicons_icons.dart';
Machine machine;
class WorkshopTool extends StatefulWidget {
final String rotary;
WorkshopTool(this.rotary);
@override
_WorkshopToolState createState() => _WorkshopToolState(rotary);
}
class _WorkshopToolState extends State<WorkshopTool> {
String rotary;
bool _showOnScreen = true;
_WorkshopToolState(this.rotary);
@override
Widget build(BuildContext context) {
var screenSize = MediaQuery.of(context).size;
return FutureBuilder(
future: Firestore.instance
.collection('productionrpt')
.document(rotary)
.get(),
builder: (context, snapshot) {
if (!snapshot.hasData)
return Container(
height: screenSize.height - 50.0,
child: Center(
child: SizedBox(
height: 80.0,
width: 80.0,
child: CircularProgressIndicator(
valueColor:
AlwaysStoppedAnimation<Color>(Colors.green[600]),
strokeWidth: 15.0,
)),
));
machine = Machine.fromMapObjext(snapshot.data);
return Container(
height: screenSize.height - 50.0,
width: screenSize.width,
child: Stack(
children: <Widget>[
SingleChildScrollView(
child: Column(
children: <Widget>[
//To make a empty column space for stack on top
Container(
height: 80.0,
padding: EdgeInsets.only(bottom: 5.0, right: 15.0),
child: Align(
alignment: Alignment.bottomRight,
child: Text(
machine.date,
style: TextStyle(
color: Colors.black,
fontSize: 17.0,
fontStyle: FontStyle.italic,
fontWeight: FontWeight.bold),
),
),
),
FancyTextField('Production'),
FancyTextField('Damages'),
FancyTextField('Plan'),
SizedBox(
height: 20.0,
),
Padding(
padding: EdgeInsets.only(
bottom:
MediaQuery.of(context).viewInsets.bottom)),
],
),
),
Container(
height: 50.0,
decoration: BoxDecoration(
color: Colors.green[400],
borderRadius:
BorderRadius.vertical(top: Radius.circular(15.0))),
),
Align(
alignment: Alignment.bottomRight,
child: Padding(
padding: const EdgeInsets.all(20.0),
child: MaterialButton(
color: Colors.black,
padding: EdgeInsets.only(
top: 10.0, bottom: 10.0, left: 20.0, right: 20.0),
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(15.0)),
child: Text(
'UPDATE',
style: TextStyle(
fontSize: 30.0,
fontWeight: FontWeight.bold,
color: Colors.white),
),
onPressed: () {
print('Saved to cloud : ${machine.production}');
firebasePutData();
}),
),
),
Align(
alignment: Alignment.bottomLeft,
child: Padding(
padding: EdgeInsets.all(20.0),
child: StatusButton(),
),
),
Align(
alignment: Alignment.topLeft,
child: IconButton(
icon: Icon(
Icons.close,
size: 40,
color: Colors.black,
),
onPressed: () {
print('Bottomsheet closed');
}),
),
Align(
alignment: Alignment.topCenter,
child: Padding(
padding: const EdgeInsets.all(10.0),
child: Text(
machine.rotary,
style: TextStyle(
color: Colors.black,
fontSize: 20.0,
decoration: TextDecoration.underline,
fontWeight: FontWeight.bold),
),
),
),
Padding(
padding: const EdgeInsets.all(4.0),
child: Align(
alignment: Alignment.topRight,
child: Switch(
value: _showOnScreen,
activeTrackColor: Colors.black54,
activeColor: Colors.black,
inactiveThumbColor: Colors.grey[600],
inactiveTrackColor: Colors.grey[500],
onChanged: (v) {
_showOnScreen = !_showOnScreen;
print('Switch tapped');
}),
),
),
],
),
);
});
}
void firebasePutData() {
Firestore.instance
.collection("productionrpt")
.document(rotary)
.updateData(machine.toMap());
print('Data updated');
}
} //End of main page STATE (a bottom sheet)
//#######################################################################################################
//############ FANCY TEXT FIELD FOR ENTERING MACHINE DATA #################
class FancyTextField extends StatefulWidget {
final String _title;
FancyTextField(
this._title,
);
@override
_FancyTextFieldState createState() => _FancyTextFieldState(this._title);
}
class _FancyTextFieldState extends State<FancyTextField> {
final String _title;
final TextEditingController _ctrl = TextEditingController();
_FancyTextFieldState(this._title);
@override
void initState() {
switch (_title) {
case 'Production':
_ctrl.text = machine.production.toString();
break;
case 'Plan':
_ctrl.text = machine.plan.toString();
break;
case 'Damages':
_ctrl.text = machine.damage.toString();
break;
}
super.initState();
}
@override
Widget build(BuildContext context) {
return Container(
height: 125.0,
margin: EdgeInsets.all(8.0),
decoration: BoxDecoration(
color: Colors.green[400],
borderRadius: BorderRadius.circular(15.0),
// boxShadow: [
// BoxShadow(
// blurRadius: 5, color: Colors.green[300], spreadRadius: 5)
// ]
),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
_title,
style: TextStyle(
color: Colors.black,
fontSize: 23.0,
fontWeight: FontWeight.bold),
),
Container(
height: 50,
width: 300,
alignment: Alignment.center,
padding: const EdgeInsets.all(5.0),
margin: const EdgeInsets.only(
top: 10.0, bottom: 10, left: 30.0, right: 30.0),
decoration: BoxDecoration(
color: Colors.white70,
borderRadius: BorderRadius.circular(10),
),
child: TextField(
//maxLength: 5,
controller: _ctrl,
textAlign: TextAlign.center,
keyboardType: TextInputType.number,
style: TextStyle(
color: Colors.black,
fontSize: 30.0,
),
decoration: InputDecoration(
border: InputBorder.none,
),
onChanged: (v) {
switch (_title) {
case 'Production':
machine.production = int.parse(_ctrl.text);
break;
case 'Plan':
machine.plan = int.parse(_ctrl.text);
break;
case 'Damages':
machine.damage = int.parse(_ctrl.text);
break;
}
print('Prod: ${machine.production}');
},
),
),
],
),
);
}
} //END OF CLASS FANCY TEXT FIELD
//######################################################################################################
//####### A STATEFUL WIDGET FOR MACHINE STATUS BUTTON : running, off, breakdown ##########
class StatusButton extends StatefulWidget {
@override
_StatusButtonState createState() => _StatusButtonState();
}
class _StatusButtonState extends State<StatusButton> {
Color color;
IconData icon;
@override
Widget build(BuildContext context) {
switch (machine.stats) {
case 0:
color = Colors.grey[600];
icon = Icons.power_settings_new;
break;
case 1:
color = Colors.blue;
icon = Icons.power_settings_new;
break;
default:
color = Colors.red;
icon = Kalaicons.breakdown;
break;
}
return Container(
height: 70.0,
width: 70.0,
decoration: BoxDecoration(
color: color,
shape: BoxShape.circle,
),
child: IconButton(
icon: Icon(
icon,
color: Colors.white,
size: 50.0,
),
onPressed: () {
setState(() {
machine.stats > 1 ? machine.stats = 0 : machine.stats++;
print('Status button pressed: ${machine.stats}');
});
},
));
}
} //END OF CLASS STATUS BUTTON
我的模特:
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:intl/intl.dart';
class Machine {
int _production;
int _plan;
int _damage;
int _stats = 0;
String _date = '~Not available';
String _rotary;
// Machine(this._production, this._damage, this._date,
// [this._stats, this._plan]);
int get production => this._production;
int get plan => this._plan;
int get damage => this._damage;
int get stats => this._stats;
String get date => this._date;
String get rotary => this._rotary;
set production(int updatedValue) {
if (updatedValue != null) {
this._production = updatedValue;
}
}
set plan(int updatedValue) {
if (updatedValue != null) {
this._plan = updatedValue;
}
}
set damage(int updatedValue) {
if (updatedValue != null) {
this._damage = updatedValue;
}
}
set stats(int updatedValue) {
this._stats = updatedValue;
}
// set date(String updatedValue) {
// this._date = DateFormat.jm().format(DateTime.now());
//
// }
//Function to set a map list of new data for firebase
Map<String, dynamic> toMap() {
var map = Map<String, dynamic>();
map['production'] = this._production;
map['plan'] = this._plan;
map['damages'] = this._damage;
map['stats'] = this._stats;
map['date'] = DateFormat("MMMM dd, hh:mm a").format(DateTime.now());
return map;
}
//Constructor to extract firebase collections
Machine.fromMapObjext(DocumentSnapshot map) {
this._production = map['production'];
this._plan = map['plan'];
this._damage = map['damages'];
this._stats = map['stats'];
this._date = map['date'];
this._rotary = map['machine'];
}
}
最近更新:
StatusButton的值被gettiong更新为对象和firestore。但是，更新后的FancyTextField的值仅反射(reflect)在该类本身内部。不全局更新。
最佳答案
最后，我自己发现问题持续了3天。发生问题是因为弹出键盘时，该小部件也会使其状态重建。由于我的Firebase数据已在构建中的FutureBuilder上存储，因此我的旧数据将再次从Firebase中调出并将其保存在新编辑的数据之上。
为什么我放在TextField上的初始文本没有更改？
因为我已经将它设置在initState类的FancyTextField上，所以在重建小部件时，我将不会执行，并且编辑后的值将保持不变。
为什么更新StatusButton值而不失败？
因为当我点击按钮键盘时，不会弹出，并且构建也不会重新构建。但是后来我注意到，在将StatusButton状态更改为其他值并点击TextField使其变为OLD值(即当前在Firebase中的值)之后。由于构建是重新创建的。我就是这样想的。
我为克服此问题所做的工作:
我只是简单地删除了从firebase获取数据的FutureBuilder，并为其创建了Future并在initState中启动。
如果有人愿意，我可以在这里显示更新的代码
关于flutter - 在Flutter Dart中访问和修改来自不同类的变量，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/61009328/