Since the day I started learning software, the first thing I have seen, read and heard from all sources, social media accounts, online trainings and scholars of this business has been “code, practice, try to write”.
The second thing is “read other people’s code”. But why and how? How can reading code benefit me? Where to start? Do you read code like a book? So many questions in my head. And the interesting thing is that this is a recommendation that is said to be valid when learning every language, every framework of software. No matter what you are learning, this advice never changes. So I’ve gotten quite advanced in reading code by focusing on this topic, researching, starting from simple code snippets, reading and reading — sometimes I even continued without understanding it.
Then I realized that reading code is a very valuable skill in the software world and understanding the code written by others helps me to become a better developer in my own projects and to work more effectively in a team. Learning to read code seems difficult at the beginning, it was for me too, but I have prepared for you what I did and what I learned in this process by quoting from different sources and I think you can improve it by taking it step by step. Here is a detailed roadmap for you:
What is Code Reading and Why is it Important?
Code reading means analyzing and understanding code written by someone else. Through this skill:
- You learn new techniques and methods.
- Improve your ability to debug and optimize existing code.
- You gain different perspectives to become a better software developer.
Learning to read code is like learning a language: It involves understanding words, sentences and paragraph structures.
How to Start Code Reading?
Start with Small and Simple Code:
It’s best to start with simple and well-documented code samples.
Check GitHub or the official sample projects of the technology you’re using. For example, if you’re learning Flutter, Flutter’s “counter” sample app is a good place to start.
Understand the purpose of the code:
Before you start reading, find out what the code does. Read the project’s README file or description.
Is the code running on a page, or is it connecting to an API? Knowing this makes your job easier.
Progress piece by piece:
Instead of trying to understand the entire code at once, focus on small sections. For example, in a Flutter project, start by looking only at the “main.dart” file.
Focus on Variables and Functions:
Variable names and functions usually describe the purpose of the code. For example, if a variable is named totalCost, you can guess that it is related to total cost.
Read the Comments:
Comment lines (starting with //) and documentation help you understand the logic of the code. Pay attention to these comments.
Watch the Code Run:
Run the code in a development environment to see how it works. Observe which pieces of code produce which results.
Steps You Can Follow During Code Reading
Make an Overview:
Take a quick look at the files. Get an idea by looking at the names and structure of the files.
Focus on Functions and Methods:
Pay attention to the parts of the code that perform the most basic functions. If an application allows a user to log in, look for functions named “login” or “authenticate”.
Follow the Flow:
Follow the flow of the code by going through the starting point of the program (usually the main function).
Search for Difficult Parts:
When you see an unfamiliar structure, library or method, look it up. Stack Overflow, GitHub or documentation are the best resources for this.
Ask Questions and Take Notes:
Asking questions like “Why is this done?”, “What does this variable do?” while reading code increases your understanding.
Recommendations for Practicing Code Reading
Review Small Open Source Projects:
Find and review small projects on platforms like GitHub. Simple todo lists, counter apps, or basic web projects are ideal.
Read Your Own Projects:
Look back at the code you’ve written before. Asking yourself “Why did I do it this way?” will also help you learn.
Participate in Code Reviews:
If you work in a team, get involved in code review processes. In these processes, you will witness different writing styles and approaches.
Tools to Improve Code Reading
Linter Usage:
Tools that improve code readability (e.g. dart analyze for Flutter) show code errors and warnings.
Debugging Tools:
Use debugging tools to understand what is happening while the code is running. This helps you see which variables changed and when.
Version Control (Git):
Use Git to look at the history of the code. It is useful to examine the differences between previous versions of the code and the current version.
Up to this point, I’ve listed general things such as what code reading is, how it can be read, which steps can be followed. But I felt the need to learn how to read code after I started working with Flutter. Therefore, in the rest of this article, I want to talk about how to read code specifically for Flutter and where to start.
Code Reading in Flutter
Reading code in Flutter seems to be more difficult at the beginning than in other languages, it seemed that way to me. There are a few reasons for this.
The first one is Flutter’s Widget Structure. Everything in Flutter is a widget and widgets are nested. At first, this structure may make you think “Where does the code start and where does it end?”.
The second is Flutter’s dynamism. Especially features like animation and state management can make it difficult to understand the flow of the code.
The third is Flutter’s packages. Many Flutter projects use dependencies from the pubspec.yam file. A function or widget you see in the code may come from another package.
Being aware of these difficulties makes you patient with yourself while reading. I say this because I have experienced it myself. Now let’s see how to read code in Flutter step by step.
Recognize the Structure of Flutter Projects
Understanding the overall file structure of a Flutter project makes the code reading process easier. A typical project looks like this:
lib/
|- main.dart
|- screens/
|- home_screen.dart
|- settings_screen.dart
|- widgets/
|- custom_button.dart
|- models/
|- user_model.dartUnderstanding main.dart File
main.dart is the entry point of every Flutter application. Review this file before reading code:
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const HomeScreen(),
);
}
}Ask the following questions when reviewing this code:
What does runApp do? (Answer: Launches the application.)
What type of widget is MyApp? (Answer: StatelessWidget.)
What is inside MaterialApp? (Answer: Theme, header and home screen information.)
Understand Widget Hierarchy in Flutte
Understanding the widget hierarchy is key to reading Flutter code. For example, let’s look at Flutter’s standard counter implementation:
class CounterScreen extends StatefulWidget {
const CounterScreen({Key? key}) : super(key: key);
@override
_CounterScreenState createState() => _CounterScreenState();
}
class _CounterScreenState extends State<CounterScreen> {
int _counter = 0;
void _incrementCounter() {
setState(() {
_counter++;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Counter App'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text('You have pushed the button this many times:'),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: const Icon(Icons.add),
),
);
}
}When reading this code, pay attention to the following:
Scaffold provides the main skeleton of the app (appBar, body, floatingActionButton).
Why is setState used? (Answer: To update the UI when the state changes.)
How are the widgets in Column arranged? (Answer: In a vertical layout, centered using mainAxisAlignment.)
Watch Code Flow
Follow the flow to understand how widgets work:
Starting Point: Find the home widget in the main.dart file.
Go from one widget to another: For example, if a button in HomeScreen redirects to another screen, see what function that button calls.
Example: Understanding Navigation Flow
class HomeScreen extends StatelessWidget {
const HomeScreen({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Home'),
),
body: Center(
child: ElevatedButton(
onPressed: () {
Navigator.push(
context,
MaterialPageRoute(builder: (context) => const SettingsScreen()),
);
},
child: const Text('Go to Settings'),
),
),
);
}
}What does Navigator.push do? (Answer: It takes the user to another screen called SettingsScreen.)
Find and analyze the SettingsScreen in the code.
Explore Packages and Libraries
Flutter projects often use packages and libraries. For example, if a project uses the http package, you might see the following in the code:
import 'package:http/http.dart' as http;
Future<void> fetchData() async {
final response = await http.get(Uri.parse('https://api.example.com/data'));
if (response.statusCode == 200) {
print(response.body);
} else {
throw Exception('Failed to load data');
}
}What is http.get and what does it do? Check the HTTP package documentation for more information about this package.
Follow the code step by step and try to understand how the data is processed.
Tips for Practicing Code Reading
Run and Experience Flutter Projects:
Run in an IDE (e.g. VS Code) to see how the code works. Change widget properties and observe how it is affected.
Start with Simple Code and Widgets:
Learn how to use basic widgets like Container, Row, Column, Text, Button. For example, modify the code to understand how widgets in a Row are placed side by side.
Focus on State Management Codes:
Constructs such as setState, Provider, or Riverpod will help you understand how the code works in depth.
More Suggestions
Use Flutter Sample Code: There are plenty of examples in Flutter’s official documentation and on GitHub. For example, you can check out the Material3 Demo repo.
Make Progress by Asking Questions: Questions like “What does this widget do?”, “Which library is used for what?” will deepen your understanding.
Read Your Own Projects: Look at the Flutter projects you’ve written before and think, “How could I have done it better?”
Last but not least Be Patient!
Reading code is a skill that develops over time. It’s normal to struggle at first, but with regular practice you’ll get faster and easier to understand. Once you gain confidence with simple code to start with, you can move on to more complex projects.
Thank you so much for reading.
Selin.
