State & Input in Kotlin Desktop: Compose Multiplatform | Lesson 03

Learn how to manage state and handle user input in Compose Desktop! In this lesson we build a settings form with OutlinedTextField, Checkbox, Switch, and RadioButton. We explore state hoisting, data class copy() for immutable updates, and pure validation functions. What You'll Learn: - OutlinedTextField with value/onValueChange two-way binding - Checkbox with checked/onCheckedChange - Switch with checked/onCheckedChange - RadioButton with selected/onClick in a forEach loop - State hoisting: parent owns state, child is stateless - remember { mutableStateOf() } for local state - Data class copy() for immutable state updates - Pure validation function returning nullable error string - isError and supportingText for input validation - Reusable composables (SectionLabel) Source Code: https://github.com/GoCelesteAI/kotlin-desktop-lesson03-settings-app Timestamps: 0:00 - Introduction 0:15 - Preview: What We're Building 0:45 - Project Setup (from scratch) 2:15 - State & Input Controls 3:45 - State Hoisting 4:45 - Live Demo: Settings Form 5:45 - Recap & Key Takeaways 6:45 - End Screen Key Takeaways: 1. TextField — OutlinedTextField uses value/onValueChange for two-way data binding 2. Controls — Checkbox, Switch, RadioButton follow checked/onCheckedChange pattern 3. State Hoisting — Parent owns state, child receives it and fires callbacks 4. Data Class copy() — Create new state instances with specific fields changed 5. Validation — Pure functions return nullable error strings If you found this helpful, please like and subscribe for more Kotlin Desktop tutorials!