ConstrainedBox Widget

 import "package:flutter/material.dart";

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: "hello",
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blueGrey,
      ),
      home: const FlutterApp(),
    );
  }
}

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

  @override
  State<StatefulWidget> createState() {
    return FlutterAppState();
  }
}

class FlutterAppState extends State<FlutterApp> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      drawer: Drawer(
        child: ListView(
          padding: EdgeInsets.zero,
          children: [
            const UserAccountsDrawerHeader(
              accountName: Text("John"),
              accountEmail: Text("John123@google.com"),
              currentAccountPicture: Icon(
                Icons.account_circle,
                size: 85,
              ),
            ),
            ListTile(
              leading: const Icon(Icons.message),
              title: const Text("message"),
              onTap: () {
                Navigator.pop(context);
              },
            ),
            const Divider(thickness: 1, color: Colors.black),
            ListTile(
              leading: const Icon(Icons.account_circle),
              title: const Text("profile"),
              onTap: () {
                Navigator.pop(context);
              },
            ),
            const Divider(thickness: 1, color: Colors.black),
            ListTile(
              leading: const Icon(Icons.settings),
              title: const Text("settings"),
              onTap: () {
                Navigator.pop(context);
              },
            ),
            const Divider(thickness: 1, color: Colors.black),
            ListTile(
              leading: const Icon(Icons.help_outline),
              title: const Text("Help & feedback"),
              onTap: () {
                Navigator.pop(context);
              },
            ),
            const Divider(thickness: 1, color: Colors.black),
            ListTile(
              leading: const Icon(Icons.restore_from_trash),
              title: const Text("Trash"),
              onTap: () {
                Navigator.pop(context);
              },
            ),
          ],
        ),
      ),
      appBar: AppBar(
        title: const Text(
          "Flutter Constraint box",
          style: TextStyle(fontWeight: FontWeight.bold),
        ),
        centerTitle: true,
        backgroundColor: Colors.grey,
      ),
      /*By default,ConstrainedBox() contains only one child*/

      body: Center(
        child: ConstrainedBox(
          constraints: const BoxConstraints(
            maxWidth: 300,
            minWidth: 200,
            /*here,button will adopt minWidth & minHeight as specified*/
            maxHeight: 300,
            minHeight: 100,
          ),
          /*child: const Text("Hello World.How are you ?.Welcome.Hello Flutter.Hello World.Next time we will meet in the morning",
              style: TextStyle(fontSize: 21, overflow: TextOverflow.fade),)),*/

          child: ElevatedButton(
            onPressed: () {},
            style: ElevatedButton.styleFrom(
              backgroundColor: Colors.blue,
            ),
            child: const Text(
              "Click!",
              style: TextStyle(
                  fontWeight: FontWeight.bold,
                  fontSize: 20.0,
                  color: Colors.white),
            ),
          ),
        ),
      ),
    );
  }
}