如何在Dart中两个屏幕之间传递数据

Question

我需要使用dart将数据发送到另一个屏幕，我试图在另一个屏幕上构造函数(editdata.dart)从主屏幕(readdata.dart)获取数据，这是有状态小部件的问题:createState() => EditFire()EditFire类需要传递参数，但我还没有数据。

editdata.dart:

class EditData extends StatefulWidget {
@override
//Here the Error Occurs//
State<StatefulWidget> createState() => EditFire();
}
class EditFire extends State<EditData> {
EditFire(String ID, String date, String time, String dest, String src){
currentID = ID;
olddate = date;
oldtime = time;
_destinationcontroller.text = dest;
_sourcecontroller.text = src;
}
late String currentID;
final _destinationcontroller = TextEditingController();
final _sourcecontroller = TextEditingController();
late String olddate;
late String oldtime;
}

在readdata.dart:

EditFire("2","17/6/2022","2:25","NewYork","Japan");

Answer 1

首页

onPressed: () { 
Navigator.of(context).push(MaterialPageRoute(builder: (_){
return EditData("2","17/6/2022","2:25","NewYork","Japan");
}));
},

要接收数据的第二页

class EditData extends StatefulWidget {
String currentID;
String _destinationcontroller;
String _sourcecontroller;
String olddate;
String oldtime;

EditData(this.currentID, this._destinationcontroller, this._sourcecontroller,
this.olddate, this.oldtime, {Key? key}) : super(key: key);
@override
State<EditData> createState() => _EditDataState();
}
class _EditDataState extends State<EditData> {
@override
Widget build(BuildContext context) {
return Container(
child: Center(child:
Text('${widget.currentID}'),),
);
}
}

Answer 2

访问EditData的数据到EditFire，你不需要在构造函数中传递它。可以看到EditFire是EditData的状态.

所以如果你想在EditFire中获取任何内容在EditData中使用，您可以使用widget.abc

class EditData extends StatefulWidget {
// here, in constructor of widget, we are gathering values.
EditData(
{required this.currentID,
required this.olddate,
required this.oldtime,
Key? key})
: super(key: key);
String currentID;
String olddate;
String oldtime;
State<StatefulWidget> createState() => EditFire();
}
// this is a state widget of EditData. so no need to pass value in constructor of state widget.
class EditFire extends State<EditData> {
final _destinationcontroller = TextEditingController();
final _sourcecontroller = TextEditingController();
String? currentID;
String? olddate;
String? oldtime;
@override
void initState() {
super.initState();
// you can get the values like this
currentID = widget.currentID;
olddate = widget.olddate;
oldtime = widget.oldtime;
}
}

要将值传递给EditData，需要将其传递给构造函数。如,

EditData(currentID: "", olddate: "", oldtime: "");

希望，这将解决您的问题，仍然没有解决，请评论的问题。