import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: Scaffold(
        appBar: AppBar(title: Text('Opacity TextField')),
        body: Center(
          child: Container(
            width: 100,
            height: 100,
            child: Opacity(
              opacity: 0.5,
              child: TextField(),
            ),
          ),
        ),
      ),
    );
  }
}