Calculator

A simple calculator app in Flutter that demonstrates Flutter's many features. The calculator is not complete and only supports basic operations (and may have a bug or two).

I made this so you guys can see how a real-world app might be structured and how functionality is implemented. I've left A LOT of comments in the code to explain what's going on. I also hope this can be a good reference for you guys when you're working on the project we're gonna cook up.

I heavily recommend reading through the code and experimenting by running the app and changing things to see how it all works!

I'd suggest starting by looking at the main.dart file and then moving on to the home_screen.dart file, and then just branching out to what interests you most. Remember that you can CTRL + click on a function or class or anything when in VSCode to jump to its definition or where it's used, and hover over Flutter classes/functions to view their documentation.

Please ask questions in the Discord if something doesn't make sense or if you want to know more about something!

File structure

• lib/main.dart : The entry point of the application. It's where we define the global theme of the app and the initial widget to use as our homepage.

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• lib/logic : The logic folder contains the business logic of the app.
• lib/logic/calculator.dart : This file contains the Calculator class which is responsible for the calculations in the app.
• lib/logic/exceptions.dart : This file contains the custom exceptions used in the app.

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• lib/ui : The ui folder contains the user interface of the app.
• lib/ui/home_screen.dart : This file contains the HomeScreen widget which is the main and only screen of the app.
• lib/ui/views : This folder contains the two "views" in HomeScreen, the top "number view" where the user sees the numbers and the bottom "button view" where the user presses a grid of buttons.
• lib/ui/components : This folder contains the components used in the app. There's just one component, the CalculatorButton widget which is a custom button widget used in the grid of buttons.

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In a more complicated app, we might split things up even more, such as having separate folders for separate screens and so on. But for this simple app, this structure is enough.

Screenshots