Lists & Navigation in Kotlin Desktop: Compose Multiplatform | Lesson 04

Learn how to build scrollable lists and navigate between screens in Compose Desktop! In this lesson we build a notes app with LazyColumn for efficient list rendering, sealed classes for type-safe navigation, and a when expression for state-driven screen routing. What You'll Learn: - LazyColumn with items() DSL for efficient scrollable lists - Card(onClick = ...) for clickable list items - sealed class for type-safe navigation screens - when expression for state-driven screen routing - State hoisting for navigation: parent owns currentScreen - verticalScroll(rememberScrollState()) for scrollable detail - Reusable TopBar composable with optional back button Source Code: https://github.com/GoCelesteAI/kotlin-desktop-lesson04 Timestamps: 0:00 - Introduction 0:15 - Preview: What We're Building 0:45 - Project Setup 1:30 - Data Model 2:20 - List Composables 3:10 - Detail & TopBar 4:00 - Main & Compile 4:45 - Live Demo 5:45 - Recap & Key Takeaways 6:45 - End Screen Key Takeaways: 1. LazyColumn — Renders only visible items for efficient scrolling 2. Sealed Class — Type-safe navigation with Screen.List and Screen.Detail 3. When Expression — Pattern-match current screen to render the right composable 4. Navigation State — Parent owns currentScreen, children fire callbacks 5. Card onClick — Make entire cards clickable with one parameter Next Lesson: Lesson 05: Theming & Dark Mode (coming soon)