to do

import 'package:flutter/material.dart';

void main() => runApp(MaterialApp(
  home: Scaffold(
    appBar: AppBar(
      title: Text('demo App'),
      centerTitle: true,
    ),
    body: mainApp(),
  ),
));

class mainApp extends StatefulWidget {
  @override
  _mainAppState createState() => _mainAppState();
}

class _mainAppState extends State<mainApp> {

  var txt = TextEditingController();
  final List<String> names = <String>['Paweł','Ania','Michał','Władek'];
  int size = 4;

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Container(
        child: Column(
          children: <Widget>[
            Container(
              color: Colors.teal,
              padding: EdgeInsets.all(30),
              margin: EdgeInsets.only(
                bottom: 20,
              ),
              child: TextField(
                controller: txt,
                onSubmitted: (String str)
                {
                  setState(() {
                    names.insert(0, str);
                    size++;
                    txt.text = "";
                  });
                },
                decoration: InputDecoration(
                    hintText: 'Insert text here!'
                ),
              ),
            ),
            Expanded(
              child: ListView.builder(
                  itemCount: size,
                  itemBuilder: (_context, index)
                  {
                    return Container(
                      margin: EdgeInsets.all(10),
                      padding: EdgeInsets.all(12),
                      decoration: BoxDecoration(
                          color: Colors.teal,
                          borderRadius: BorderRadius.only(
                            topRight: Radius.circular(10),
                            topLeft: Radius.circular(10),
                            bottomRight: Radius.circular(10),
                            bottomLeft: Radius.circular(10),
                        )
                      ),
                      child: Row(
                        mainAxisAlignment: MainAxisAlignment.spaceBetween,
                        children: <Widget>[
                          Container(
                            child: Text('Id: $index Name: ${names[index]}'),
                          ),
                          GestureDetector(
                            onTap: ()
                            {
                              //remove
                              setState(() {
                                names.removeAt(index);
                                size--;
                              });
                            },
                            child: Container(
                              child: Icon(Icons.remove),
                              color: Colors.greenAccent,
                            ),
                          )
                        ],
                      ),
                    );
                  }
              ),
            )
          ],
        ),
      )
    );
  }
}