update tabbar widget from appbar textfield in flutter

Question

I need to update tab 1 screen's list view based on textfield value which is placed in TabDemoScreen class's Appbar. while tab1 is selected , textfiled should be editable(able to type). and when i select tab2 textfiled should be act as dropdown list view. Now my problem is after submitting value while tab1 is selected, unable to update listview on tab1.Unable to access setState of Tab1.

class TabsDemoScreen extends StatefulWidget {
  @override
 _TabsDemoScreenState createState() => _TabsDemoScreenState();
}

class _TabsDemoScreenState extends State<TabsDemoScreen> {

  int currentTabIndex = 1;

  List<Widget> tabs = [
   Tab1(),
  Tab2()
 ];

  return Scaffold(
  appBar: AppBar(
    title: Container(width: 200, height: 40,
        child: TextField(
            onSubmitted: (value) {
              // **do some action and update Tab1 screen**
        },)),
  ),
  body: tabs[currentTabIndex]);

}

class Tab1 extends StatefulWidget {
 @override
 Tab1State createState() => Tab1State();
}

 class Tab1State extends State<Tab1> {
 }

 class Tab2 extends StatefulWidget {
 @override
 Tab2State createState() => Tab2State();
}

class Tab2State extends State<Tab2> <Tab2> {
}