问题描述
我创建了一个文件，在其中创建底部导航和抽屉，当我登录后运行应用程序时，它向我发送此错误。
错误：
The following ArgumentError was thrown building EmployeeDashboard(dirty,state: _EmployeeDashboardState#e749a):
Invalid argument(s)
但工作正常，它在模拟器上没有显示任何红屏，但是当我在手机上运行该应用程序时，它显示红屏并显示“无效参数”错误
这是我的代码
class EmployeeNavigation extends StatefulWidget {
@override
State<StatefulWidget> createState() {
return EmployeeNavigationState();
}
}
String getname;
String getemail;
String getdesignation;
class EmployeeNavigationState extends State<EmployeeNavigation> {
int _selectedTab = 0;
final _pageOptions = [
EmployeeDashboard(),// It's pointing over here
Profile(),//SearchPage(),];
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
),drawer: Emp_DrawerCode(),body: _pageOptions[_selectedTab],bottomNavigationBar: BottomNavigationBar(
currentIndex: _selectedTab,onTap: (int index) {
setState(() {
_selectedTab = index;
});
},items: [
BottomNavigationBarItem(
icon: Icon(Icons.home),title: Text('Home'),),BottomNavigationBarItem(
icon: Icon(Icons.person),title: Text('Profile'),],);
}
}
-------------------------更新----------------- --------------------
这里是EmployeeDashboard文件
class EmployeeDashboard extends StatefulWidget {
@override
_EmployeeDashboardState createState() => _EmployeeDashboardState();
}
class _EmployeeDashboardState extends State<EmployeeDashboard> {
String getTime;
bool valuefirst = false;
String getname;
String getemail;
String getdesignation;
bool getTimeInStatus;
String getaccesstoken;
@override
void initState() {
_userDetails();
_getTime();
}
_userDetails() async{
SharedPreferences myPrefs=await SharedPreferences.getInstance();
setState(() {
getname=myPrefs.getString('name');
getdesignation=myPrefs.getString('designation');
getTimeInStatus=myPrefs.getBool('timeInStatus');
getaccesstoken=myPrefs.getString('accesstoken');
});
}
var localhostUrlTimeIn="http://192.168.1.105:8000/TimeIn";
var localhostUrlTimeOut="http://192.168.1.105:8000/TimeOut";
calltimeInApi() async {
dio dio=new dio();
var data={
'username': getname,'token': getaccesstoken
};
await dio
.post(localhostUrlTimeIn,data: json.encode(data))
.then((onResponse)async {
print(onResponse.headers);
print(onResponse.statusCode);
print(onResponse.data);
}).catchError((onerror){
print(onerror.toString());
//showAlertDialog(context);
});
}
calltimeOutApi() async {
dio dio=new dio();
var data={
'username': getname,'token': getaccesstoken
};
await dio
.post(localhostUrlTimeOut,data: json.encode(data))
.then((onResponse)async {
print(onResponse.headers);
print(onResponse.statusCode);
print(onResponse.data);
}).catchError((onerror){
print(onerror.toString());
//showAlertDialog(context);
});
}
void _getTime() {
final String formattedDateTime =
DateFormat('kk:mm:ss').format(DateTime.Now()).toString();
setState(() {
getTime = formattedDateTime;
print(getTime[0]);
});
}
String _formatDateTime(DateTime dateTime) {
return DateFormat('MM/dd/yyyy hh:mm:ss').format(dateTime);
}
String timeInText=" Time in";
String timeOutText=" Time out";
bool timeInButtonpressed=false;
bool timeOutButtonpressed=false;
// ignore: missing_return
Widget _timein() {
//enable
if(getTimeInStatus==false) {
return RoundedButton(icon: Icon(Icons.timer,color: Colors.white),text:timeInText,bgcolor: timeInButtonpressed ?Colors.blue[200]:Colors.blue[500],press: () {
_getTime();
setState(() {
timeInText=" "+getTime;
});
calltimeInApi();
timeOutButtonpressed=true;
});
}
//disable
else if(getTimeInStatus==true) {
return RoundedButton(icon: Icon(Icons.timer,bgcolor: Colors.blue[200],);
}
}
// ignore: missing_return
Widget _timeout(){
//enable
if(timeInText!=" Time in") {
return RoundedButton(icon: Icon(Icons.timer,text:timeOutText,bgcolor: timeOutButtonpressed ?Colors.blue[500]:Colors.blue[200],press: () {
_getTime();
setState(() {
timeOutText=" "+getTime;
});
calltimeOutApi();
});
}
//disable
else if(timeOutButtonpressed==false){
return RoundedButton(icon: Icon(Icons.timer,bgcolor: Colors.blue[200]);
}
}
@override
Widget build(BuildContext context) {
return new Scaffold(
body:
Stack(
children:[
Container(
color: Colors.white,child:
Row(
children: <Widget>[
SizedBox(width: 30,Text('Working from home?',style: TextStyle(fontSize: 20.0),CheckBox(
checkColor: Colors.greenAccent,activeColor: Colors.blue,value: this.valuefirst,onChanged: (bool value) {
setState(() {
this.valuefirst = value;
});
},Container(
child:Padding(padding: EdgeInsets.fromLTRB(32,40,0),child: AnalogClock(
decoration: Boxdecoration(
border: Border.all(width: 4.0,color: Colors.blue[900]),color: Colors.white,shape: BoxShape.circle),width: 130.0,height: 170.0,isLive: true,hourHandColor: Colors.blue[900],minuteHandColor: Colors.blue[900],showSecondHand: true,numberColor: Colors.blue[900],showNumbers: true,textScaleFactor: 1.9,showTicks: true,showDigitalClock: true,digitalClockColor: Colors.blue[900],datetime: DateTime(2020,8,4,9,11,)
),Container(
child:Padding(padding: EdgeInsets.fromLTRB(10,70,child:Column(children: <Widget>[
Textfield(text: "Welcome!",font: 27,fontcolor: Colors.blue[900],fontweight: FontWeight.bold,SizedBox(height:10),Textfield(text: getname,font: 20,Textfield(text: ""+getdesignation+" ",font: 17,fontcolor: Colors.blue[700],SizedBox(height:100,width: 30,Padding(padding: EdgeInsets.fromLTRB(30,20,15),child: _timein(),60),child:_timeout(),//logout button
Padding(padding: EdgeInsets.fromLTRB(0,20),child:SizedBox(
height: 50.0,width: 400.0,child:FlatButton(
onpressed: (){
Navigator.push(context,MaterialPageRoute(builder: (context)=>Login()));
},padding: EdgeInsets.all(0.0),child:
Image.asset(
"assets/image/logout.jpeg",fit: BoxFit.contain,))],)
)),)
);
}
}
请帮助我做错的地方。
解决方法
这个错误似乎与 TextField(text: ... ) 不能是 null 但它可以是空字符串 "" 有关。
将您的字符串变量初始化为一些像 getname="initStringForDebuggin" 这样的虚拟初始化似乎可以解决这个问题。但问题并没有完全消失。
您可能应该查看 futureBuilder() 小部件。
https://api.flutter.dev/flutter/widgets/FutureBuilder-class.html
并且可能会重写您的代码以在未来完成后首先呈现。 https://dart.dev/codelabs/async-await
据我所知，将来有一个 setState() 是不好的形式，就像你在 _userDetails() 中那样，你应该做这样的事情。
_userDetails().then((SOMERETURNVALUE) {
setState(() {
// Refresh screen.
});
}