Project design

Design the skeleton of the beginner final mini app.

Project: Task tracker app

In this five-lesson beginner final you will build a task tracker app that combines everything you have learned. In the first lesson you define a Task class and print a task.

In later lessons you will add layers for adding tasks, completing them, error handling and putting the whole flow together. Each lesson adds one piece with a code step; the starting code includes the previous lesson's solution. This shows how a real app grows.

Task class design

A Task class carries a task's title (title) and completion state (done). The constructor sets the title; done defaults to false. toString shows the state in a readable form.

class Task(val title: String) {
    var done: Boolean = false
    override fun toString(): String {
        return if (done) "[x] $title" else "[ ] $title"
    }
}

toString returns [x] title if done, otherwise [ ] title. When you print the list, each task's state is visible. This class is the foundation of the project.

Exercise Define the Task class

Define the Task class: a val title: String constructor parameter, a var done: Boolean = false property and an override fun toString(): String method (prefix "[x] " if done, otherwise "[ ] " with title). In main create val t = Task("Study Kotlin") and print it with println.

Show example solution

class Task(val title: String) {
    var done: Boolean = false
    override fun toString(): String {
        return if (done) "[x] $title" else "[ ] $title"
    }
}

fun main() {
    val t = Task("Study Kotlin")
    println(t)
}

Test yourself

What will we manage in this project?
- Orders
- Customers
- Tasks
- Invoices
Show answer

Tasks — the project is a task tracker app; you add and complete tasks.

Fill in the blank: done property

class Task(val title: String) {
    var ____: Boolean = false
}

Show answer

class Task(val title: String) {
    var done: Boolean = false
}

Match piece to role

title

Task name
done

Is it done
Task(title)

Constructor
var

Mutable

Next lesson: Classes

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies