Counter with History - Flutter Typing CST Test

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Counter with History — Flutter Code

Counter that logs all increment and decrement actions in a history list.

import 'package:flutter/material.dart';

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

class CounterHistoryApp extends StatelessWidget {
	@override
	Widget build(BuildContext context) => MaterialApp(home: CounterScreen());
}

class CounterScreen extends StatefulWidget {
	@override
	_CounterScreenState createState() => _CounterScreenState();
}

class _CounterScreenState extends State<CounterScreen> {
	int _count = 0;
	List<String> _history = [];

	void _increment() {
		setState(() {
			_count++;
			_history.add('Incremented to $_count');
		});
	}

	void _decrement() {
		setState(() {
			_count--;
			_history.add('Decremented to $_count');
		});
	}

	@override
	Widget build(BuildContext context) {
		return Scaffold(
			appBar: AppBar(title: Text('Counter with History')),
			body: Column(
				mainAxisAlignment: MainAxisAlignment.center,
				children: [
					Text('Count: $_count', style: TextStyle(fontSize: 32)),
					Row(
						mainAxisAlignment: MainAxisAlignment.center,
						children: [
							ElevatedButton(onPressed: _decrement, child: Text('-')),
							SizedBox(width: 10),
							ElevatedButton(onPressed: _increment, child: Text('+')),
						],
					),
					Expanded(
						child: ListView.builder(
							itemCount: _history.length,
							itemBuilder: (context, index) => ListTile(title: Text(_history[index])),
						),
					)
				],
			),
		);
	}
}

Flutter Language Guide

Flutter is an open-source UI framework by Google for building cross-platform mobile, web, and desktop applications using a single Dart codebase, featuring a highly performant rendering engine and a rich set of customizable widgets.

Primary Use Cases

▸Cross-platform mobile apps (iOS & Android)
▸Web applications
▸Desktop apps (macOS, Windows, Linux)
▸Startup MVP development
▸Enterprise internal tools
▸Apps requiring advanced UI/animations
▸Real-time dashboards and admin apps

Notable Features

▸Single codebase for all platforms
▸Hot reload and hot restart
▸High-performance Skia rendering engine
▸Rich built-in widget library
▸Material & Cupertino components
▸Dart AOT/JIT compilation
▸Support for custom animations
▸Strong ecosystem with Firebase

Origin & Creator

Created by Google; initial public release in 2017.

Industrial Note

Dominates fast cross-platform development for mobile-first startups, enterprise apps, fintech dashboards, e-commerce platforms, and apps requiring custom, fluid UI experiences across devices.

Quick Explain

▸Flutter compiles to native ARM and x86 code for high performance.
▸It uses its own rendering engine (Skia) to draw every pixel on screen, ensuring consistency across platforms.
▸Flutter emphasizes widget-based architecture and reactive UI programming.

Core Features

▸Widget-based UI system
▸Declarative reactive framework
▸Compiled native performance
▸Platform channel integrations
▸State management extensibility
▸Open-source package ecosystem

Learning Path

▸Dart language basics
▸Flutter widgets and layouts
▸Navigation and state management
▸Backend/API integration
▸Animations and rendering
▸Advanced topics (Isolates, channels)

Practical Examples

▸Login screen with Firebase Auth
▸REST API CRUD app
▸E-commerce UI with carts
▸Animation-heavy onboarding screens
▸Real-time chat application

Comparisons

▸More performant UI than React Native
▸More predictable rendering than native hybrids
▸More flexible than low-code tools
▸Larger binary size than pure native apps

Strengths

▸Visually consistent UI across platforms
▸Fast development with hot reload
▸Performance close to native apps
▸Massive widget and package ecosystem
▸Clean architecture with widgets and states

Limitations

▸App sizes can be slightly larger
▸Newer ecosystem compared to native
▸Heavy custom rendering requires optimization
▸Some platform APIs require channel coding

When NOT to Use

▸Apps needing extremely small binary sizes
▸Heavy native hardware interactions
▸Apps requiring platform-specific UI patterns exclusively
▸Highly specialized native-only frameworks

Cheat Sheet

▸Common widget syntax
▸Navigation patterns
▸setState vs Provider vs BLoC
▸pubspec.yaml configuration rules

FAQ

▸Why is Flutter so fast?
▸Flutter is fast because it compiles to native code and uses its own rendering engine to draw widgets directly, eliminating the JavaScript bridge.
▸Is Flutter good for beginners?
▸Yes, Flutter is beginner-friendly due to its simple widget system, hot reload, and strong documentation.
▸Does Flutter work for web?
▸Yes, Flutter supports web with the same codebase, though performance varies depending on complexity.
▸Is Flutter better than React Native?
▸Flutter is generally more consistent and performant due to its rendering engine, while React Native relies on native components and bridges.

30-Day Skill Plan

▸Week 1: Dart & basic widgets
▸Week 2: Layouts & navigation
▸Week 3: APIs & state management
▸Week 4: Animations + deployment

Final Summary

▸Flutter is a powerful cross-platform UI framework.
▸Uses a single codebase for mobile, web, and desktop.
▸Ideal for fast development with native-like performance.
▸Backed by Google and thriving community support.

Project Structure

▸lib/ -> Dart source files
▸pubspec.yaml -> Dependencies
▸android/ & ios/ -> Platform code
▸assets/ -> Images, fonts
▸main.dart -> App entry point

Monetization

▸In-app purchases
▸Subscriptions
▸Ads (AdMob, Facebook Ads)
▸Paid apps and Flutter templates

Productivity Tips

▸Use snippets and templates
▸Leverage hot reload efficiently
▸Use DevTools for debugging
▸Break UI into reusable widgets

Basic Concepts

▸Widgets and widget tree
▸Stateful vs stateless widgets
▸Layouts and constraints
▸Navigation and routing
▸Asynchronous programming with Futures/Streams
▸Package and plugin system

Official Docs

▸flutter.dev documentation
▸Dart.dev language docs
▸Firebase Flutter docs

More Flutter Typing Exercises

Flutter Stateless Widget Flutter Counter with Increment and Decrement Flutter Dark/Light Theme Toggle Flutter Counter with Reset Flutter Simple Stopwatch

Practice Other Languages

C React Python C++Rust TypeScript Kotlin PHP Java C#Ruby Mql Cql N1ql Cypher

Counter with History — Flutter Code

Counter that logs all increment and decrement actions in a history list.

import 'package:flutter/material.dart'; void main() => runApp(CounterHistoryApp()); class CounterHistoryApp extends StatelessWidget { @override Widget build(BuildContext context) => MaterialApp(home: CounterScreen()); } class CounterScreen extends StatefulWidget { @override _CounterScreenState createState() => _CounterScreenState(); } class _CounterScreenState extends State<CounterScreen> { int _count = 0; List<String> _history = []; void _increment() { setState(() { _count++; _history.add('Incremented to $_count'); }); } void _decrement() { setState(() { _count--; _history.add('Decremented to $_count'); }); } @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar(title: Text('Counter with History')), body: Column( mainAxisAlignment: MainAxisAlignment.center, children: [ Text('Count: $_count', style: TextStyle(fontSize: 32)), Row( mainAxisAlignment: MainAxisAlignment.center, children: [ ElevatedButton(onPressed: _decrement, child: Text('-')), SizedBox(width: 10), ElevatedButton(onPressed: _increment, child: Text('+')), ], ), Expanded( child: ListView.builder( itemCount: _history.length, itemBuilder: (context, index) => ListTile(title: Text(_history[index])), ), ) ], ), ); } }

Flutter Language Guide

Primary Use Cases

▸Cross-platform mobile apps (iOS & Android)
▸Web applications
▸Desktop apps (macOS, Windows, Linux)
▸Startup MVP development
▸Enterprise internal tools
▸Apps requiring advanced UI/animations
▸Real-time dashboards and admin apps

Notable Features

▸Single codebase for all platforms
▸Hot reload and hot restart
▸High-performance Skia rendering engine
▸Rich built-in widget library
▸Material & Cupertino components
▸Dart AOT/JIT compilation
▸Support for custom animations
▸Strong ecosystem with Firebase

Origin & Creator

Created by Google; initial public release in 2017.

Industrial Note

Dominates fast cross-platform development for mobile-first startups, enterprise apps, fintech dashboards, e-commerce platforms, and apps requiring custom, fluid UI experiences across devices.