main.dart

import 'package:flutter/material.dart';
import 'package:flutter_application_5/SecondPage.dart';
import 'package:flutter_application_5/SharedData.dart';
import 'package:flutter_application_5/student.dart';

void main() {
  runApp(MaterialApp(
    home: DemoClass()
  ));
}

class DemoClass extends StatelessWidget {
  const DemoClass({super.key});

  @override
  Widget build(BuildContext context) {
    return DefaultTabController(
      length: 3,
      child: Scaffold(
        appBar: AppBar(
          backgroundColor: Colors.red,
          title: Text("TabDemo"),
          bottom: TabBar(tabs: [
            Tab(
              icon: Icon(Icons.add),
              text: "Add",
            ),
            Tab(
              icon: Icon(Icons.home),
              text: "Home",
            ),
            Tab(
              icon: Icon(Icons.view_agenda_outlined),
              text: "View",
            ),
          ]),
        ),
        body: TabBarView(children: [
          DemoTabPage1(),
          DemoPage2(),
          ViewPage(),
        ]),
      ),
    );
  }
}

class MyApp1 extends StatelessWidget {
  MyApp1({Key? key}) : super(key: key);
  TextEditingController txtName = new TextEditingController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Demo"),
      ),
      body: Column(
        children: [
          TextField(
            controller: txtName,
          ),
          SizedBox(
            height: 10,
          ),
          ElevatedButton(
            onPressed: () {
              SharedData.stGlobal.add(txtName.text);
            },
            child: Text("Save")
          )
        ],
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          SharedData.name = txtName.text;

          Navigator.push(context, MaterialPageRoute(
            builder: (context) {
              return SecondPage();
            },
          ));
        },
        child: Icon(Icons.next_plan_outlined),
      ),
    );
  }
}

class DemoTabPage1 extends StatelessWidget {
  DemoTabPage1({super.key});
  TextEditingController txtName = new TextEditingController();
  TextEditingController txtNo = new TextEditingController();
  TextEditingController txtMarks1 = new TextEditingController();
  TextEditingController txtMarks2 = new TextEditingController();

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Column(
        children: [
          TextField(
            controller: txtName,
            decoration: InputDecoration(labelText: "Enter Name"),
          ),
          TextField(
            controller: txtNo,
            decoration: InputDecoration(labelText: "Enter No"),
          ),
          TextField(
            controller: txtMarks1,
            decoration: InputDecoration(labelText: "Enter Marks"),
          ),
          TextField(
            controller: txtMarks2,
            decoration: InputDecoration(labelText: "Enter Marks2"),
          ),
          ElevatedButton(
            child: Text("Save"),
            onPressed: () {
              Student newStu = new Student();

              newStu.name = txtName.text;
              newStu.no = txtNo.text;
              newStu.marks1 = int.parse(txtMarks1.text);
              newStu.marks2 = int.parse(txtMarks2.text);

              SharedData.stStudent.add(newStu);
              print(SharedData.stStudent.length);
            },
          ),
        ],
      ),
    );
  }
}

class DemoPage2 extends StatefulWidget {
  const DemoPage2({Key? key}) : super(key: key);

  @override
  State<DemoPage2> createState() => DemoPage2State();
}

class DemoPage2State extends State<DemoPage2> {
  String str = "";

  TextEditingController txtNo = new TextEditingController();
  @override
  Widget build(BuildContext context) {
    return Container(
      child: Column(
        children: [
          TextField(
            controller: txtNo,
            decoration: InputDecoration(labelText: "Enter No"),
          ),
          ElevatedButton(
            onPressed: () {
              for (int cntr = 0;
                  cntr < SharedData.stStudent.length;
                  cntr++) {
                if (SharedData.stStudent[cntr].no == txtNo.text) {
                  print(SharedData.stStudent[cntr].name);
                  str = SharedData.stStudent[cntr].name;
                  SharedData.stStudent.removeAt(cntr);
                }
              }
              setState(() {});
            },
            child: Text("Show Marks")
          ),
          Text(str)
        ],
      ),
    );
  }
}

class ViewPage extends StatelessWidget {
  const ViewPage({super.key});

  @override
  Widget build(BuildContext context) {
    return Container(
      child: ListView.builder(
        itemCount: SharedData.stStudent.length,
        itemBuilder:(context, index) {
          return ListTile(
            onTap: () {
              SharedData.selectedRecord = index;
              Navigator.push(context, MaterialPageRoute(
                builder: (context) {
                  return DetailView();
                },
              ));
            },
            title: Text(SharedData.stStudent[index].name),
          );
        } ,
      ),
    );
  }
}

class DetailView extends StatelessWidget {
  const DetailView({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Detail View")
      ),
      body: Column(children: [
        Text(SharedData.stStudent[SharedData.selectedRecord].name),
        Text(SharedData.stStudent[SharedData.selectedRecord].no),
        Text(SharedData.stStudent[SharedData.selectedRecord].marks1.toString()),
        Text(SharedData.stStudent[SharedData.selectedRecord].marks2.toString()),
      ]),
    );
  }
}

Secondpage.dart

import 'package:flutter/material.dart';
import 'package:flutter_application_5/SharedData.dart';

class SecondPage extends StatelessWidget {
  const SecondPage({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.red,
      appBar: AppBar(
        title: Text("Second Page"),
      ),
      body: ListView.builder(
        itemCount: SharedData.stGlobal.length,
        itemBuilder: (context, index) {
          return ListTile(
            title: (
              Text(SharedData.stGlobal[index])
            ),
          );
        } ,
      ),
    );
  }
}

SharedData.dart

import 'package:flutter_application_5/student.dart';

class SharedData {
  static String name = "";
  static List<String> stGlobal = [];
  static int selectedRecord = 0;

  static List<Student> stStudent = [];
}

student.dart

class Student {
  String name = "";
  String no = "";
  int marks1 = 0;
  int marks2 = 0;
}