How To Get Text Input Value On Button Click In Flutter App

import 'package:flutter/material.dart';

void main(){
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  MyHomePageState createState() {
    return new MyHomePageState();
  }
}

class MyHomePageState extends State<MyHomePage> {
  TextEditingController _textInputController = TextEditingController();
  String _showText = "";

  _onPressed() {
    setState(() {
      _showText = _textInputController.text;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          backgroundColor: Colors.amber[900],
          title: Text('Text Input Value'),
        ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            mainAxisSize: MainAxisSize.min,
            children: <Widget>[
              Text("Submitted Text: $_showText"),
              Padding(
                padding: const EdgeInsets.all(15.0),
                child: TextField(
                  controller: _textInputController,
                  autocorrect: true,
                  decoration: InputDecoration(
                      enabledBorder: OutlineInputBorder(
                        borderRadius: BorderRadius.all(Radius.circular(12.0)),
                        borderSide: BorderSide(color: Colors.black26),
                      ),
                      focusedBorder: OutlineInputBorder(
                        borderRadius: BorderRadius.all(Radius.circular(12.0)),
                        borderSide: BorderSide(color: Colors.grey),
                      ),
                      contentPadding: EdgeInsets.all(15),
                      hintText: 'Enter Text here',
                      hintStyle: TextStyle(color: Colors.black45, fontSize: 15),
                  ),
                ),
              ),
              RaisedButton(
                color: Colors.amber[900],
                onPressed: _onPressed,
                child: Text('Submit',style: TextStyle(color: Colors.white),),
              )
            ],
          ),
        ));
  }
}