import 'package:flutter/material.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(home: Scaffold(body: DemoWidget()));
  }
}

class DemoWidget extends StatefulWidget {
  const DemoWidget({super.key});

  @override
  State<DemoWidget> createState() => _DemoWidgetState();
}

class _DemoWidgetState extends State<DemoWidget> {
  bool _obscureText = true;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        alignment: Alignment.centerLeft,
        padding: const EdgeInsets.all(6),
        child: TextField(
          obscureText: _obscureText,
          decoration: InputDecoration(
            suffixIcon: IconButton(
              icon: Icon(
                _obscureText ? Icons.visibility : Icons.visibility_off,
                color: IconTheme.of(context).color,
              ),
              onPressed: () {
                setState(() {
                  _obscureText = !_obscureText;
                });
              },
            ),
          ),
        ),
      ),
    );
  }
}