Check Textfield Text Input Is Empty Or Not Using 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: Scaffold(
            appBar: AppBar(
                centerTitle: true,
                backgroundColor: Colors.white,
                title: Text('Get Text Field Value',style: TextStyle(
                    color: Colors.black
                ),)),
            body: Center(
                child: CheckTextField()
            )
        )
    );
  }
}

class CheckTextField extends StatefulWidget {
  CheckTextFieldWidget createState() => CheckTextFieldWidget();
}
class CheckTextFieldWidget extends State {
  final textController_1 = TextEditingController();
  final textController_2 = TextEditingController();
  final textController_3 = TextEditingController();
  checkTextFieldEmptyOrNot(){
    String text1,text2,text3 ;
    text1 = textController_1.text ;
    text2 = textController_2.text ;
    text3 = textController_3.text ;
    if(text1 == '' || text2 == '' || text3 == '')
    {
      print('Text Field is empty, Please Fill All Data');
    }
    else{
      print('Not Empty, All Text Input is Filled.');
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Container(
                  width: 280,
                  padding: EdgeInsets.all(10.0),
                  child: TextField(
                    controller: textController_1,
                    autocorrect: true,
                    decoration: InputDecoration(hintText: 'Enter First Name'),
                  )
              ),

              Container(
                  width: 280,
                  padding: EdgeInsets.all(10.0),
                  child: TextField(
                    controller: textController_2,
                    autocorrect: true,
                    decoration: InputDecoration(hintText: 'Enter Last Name'),
                  )
              ),

              Container(
                  width: 280,
                  padding: EdgeInsets.all(10.0),
                  child: TextField(
                    controller: textController_3,
                    autocorrect: true,
                    decoration: InputDecoration(hintText: 'Enter Email'),
                  )
              ),

              RaisedButton(
                onPressed: checkTextFieldEmptyOrNot,
                color: Colors.white,
                textColor: Colors.black,
                padding: EdgeInsets.fromLTRB(10, 10, 10, 10),
                child: Text('Check TextField is Empty or Not'),
              ),

            ],
          ),
        ));
  }
}