YAŞAM SÜRESİ — kendi widgetini yap

INPUT_PAGE.DART

import 'package:flutter/material.dart';

class InputPage extends StatefulWidget {
  @override
  State<InputPage> createState() => _InputPageState();
}

class _InputPageState extends State<InputPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(
          "YAŞAM BEKLENTİSİ",
          style: TextStyle(color: Colors.black87),
        ),
        centerTitle: true,
      ),
      body: Column(
        children: <Widget>[
          Expanded(
            child: Row(
              children: [
                Expanded(
                  child: MyContainer(),  // yazdığımız widgeti kullanıyoruz
                ),
                Expanded(
                  child: MyContainer(),
                ),
              ],
            ),
          ),
          Expanded(
            child: MyContainer(),
          ),
          Expanded(
            child: MyContainer(),
          ),
          Expanded(
            child: Row(
              children: [
                Expanded(
                  child: MyContainer(),
                ),
                Expanded(
                  child: MyContainer(renk: Colors.yellow, ), //widget parametreli
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}




class MyContainer extends StatelessWidget {           // Oluşturduğumuz Widget
final Color? renk;

MyContainer({this.renk=Colors.cyanAccent});     // constructor named parameter default color

  @override
  Widget build(BuildContext context) {
    return Container(
      margin: EdgeInsets.all(12.0),
      decoration: BoxDecoration(
        borderRadius: BorderRadius.circular(10.0),
        color: renk,                   // dışarıdan gelen rengi alacak
      ),
    );
  }
}

MAIN.DART

//import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import './input_page.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
          scaffoldBackgroundColor: Colors.lightBlue,
          primaryColor: Colors.lightBlue),
      home: InputPage(),
    );
  }
}