Unable to initialize static member in Dart

Question

I have read similar questions

1. Error: Only static members can be accessed in initializers what does this mean?
2. Dart - Only static members can accessed in initializers

But I am still unable to solve the problem.

I am sending Ip object which has a Ip string from one screen to another.

Here is Second screen's widget and state class in short.

class DrawingPage extends StatefulWidget {
  Ip ipObj;
//  String ipObj;
  DrawingPage({Key key, @required this.ipObj});
  _DrawingPageState createState() => _DrawingPageState();
}

class _DrawingPageState extends State<DrawingPage> {

  final String ip = widget.ipObj.ip;     //Error at "widget": Only Static members can be accessed in initializers


}

I have tried

1.Initializer's List.

2.Converting final to static member and then assigning ip value in initState does work.

But the value is set when initState is invoked, but I want to set value before initState.

How should I do it?

Answer 1

There are a number of options here... I'm not sure which one would be best for your case, but I usually use the second one, as I don't like to reference the 'widget' object in the state all the time:

Option 1: convert 'ip' to a field

class _DrawingPageState extends State<DrawingPage> {
  String get ip => widget.ipObj.ip;
}

Option 2: pass the ipObj in the constructor of the state:

class DrawingPage extends StatefulWidget {
  Ip ipObj;

  DrawingPage({Key key, @required this.ipObj});

 _DrawingPageState createState() => _DrawingPageState(ipObj);
}

class _DrawingPageState extends State<DrawingPage> {

  String ip;

  DrawingPageState(Ip ipObj){
    ip = ipObj.ip;
  }
}