add_count.dart

add_count.dart

import 'dart:async';
import 'package:flutter/material.dart';

class AddItemsPage extends StatefulWidget {
  @override
  AddItemsPageState createState() => AddItemsPageState();
}

class AddItemsPageState extends State<AddItemsPage> {
  // const AddItemsPage({super.key});

  CounterBloc bloc = CounterBloc();

  @override
  void dispose() {
    bloc.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          backgroundColor: Colors.white,
          foregroundColor: Colors.grey[900],
          title: const Text('Add Items'),
        ),
        // bottomNavigationBar: BottomNavigationBar(
        //   items: const <BottomNavigationBarItem>[
        //     BottomNavigationBarItem(
        //       icon: Icon(Icons.calculate),
        //       label: 'Calc',
        //     ),
        //     BottomNavigationBarItem(
        //       icon: Icon(Icons.camera),
        //       label: 'Camera',
        //     ),
        //     BottomNavigationBarItem(
        //       icon: Icon(Icons.chat),
        //       label: 'Chat',
        //     ),
        //   ],
        // ),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              StreamBuilder(
                stream: bloc.output,
                initialData: bloc.counter,
                builder: (BuildContext context, AsyncSnapshot snapshot) {
                  return Text(
                    "Angka: ${snapshot.data}",
                    style: TextStyle(
                      fontSize: 20.0,
                    ),
                  );
                },
              ),
              const SizedBox(
                width: 20.0,
              ),
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                children: [
                  IconButton(
                    onPressed: () {
                      bloc.inputan.add("minus");
                    },
                    icon: Icon(Icons.remove),
                  ),
                  IconButton(
                    onPressed: () {
                      bloc.inputan.add("add");
                    },
                    icon: Icon(Icons.add),
                  )
                ],
              ),
            ],
          ),
        ));
  }
}

class CounterBloc {
  int _counter = 0;
  int get counter => _counter;

  StreamController _inputController = StreamController();
  StreamSink get inputan => _inputController.sink;

  StreamController _outputController = StreamController();
  StreamSink get sinkOut => _outputController.sink;

  Stream get output => _outputController.stream;

  CounterBloc() {
    _inputController.stream.listen((event) {
      if (event == "add") {
        _counter++;
      } else {
        _counter--;
      }

      sinkOut.add(_counter);
    });
  }

  void dispose() {
    _inputController.close();
    _outputController.close();
  }
}