day9.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Day 9 Task',
      theme: ThemeData.dark(),
      home: MyHomePage(title: 'Day 9 task'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int counter = 0;
  String error = 'You have pushed the button this many times:';
  void increment() {
    setState(() {
      counter++;
      error = 'You have pushed the button this many times:';
    });
  }

  void decrement() {
    setState(() {
      if (counter > 0) {
        counter--;
      } else {
        error = 'You cant go below 0';
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              '$error',
            ),
            Text(
              '$counter',
              style: Theme.of(context).textTheme.headline4,
            )
          ],
        ),
      ),
      bottomNavigationBar: BottomAppBar(
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceAround,
          children: <Widget>[
            FloatingActionButton(
              child: Icon(Icons.remove),
              onPressed: () {
                decrement();
              },
              backgroundColor: Color(0xFF009688),
            ),
            FloatingActionButton(
              child: Icon(Icons.add),
              onPressed: () {
                increment();
              },
              backgroundColor: Color(0xFF009688),
            ),
          ],
        ),
      ),
      // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}