Navigation in Compose
All Kotlin topicsLast updated: Jun 11, 2026
∙ Topic
Navigation in Compose
Navigation in Compose teaches you how to build lifecycle-aware Android interfaces. This lesson combines idiomatic Kotlin, a runnable JVM example, and production-focused guidance.
📝Syntax
class MainActivity : ComponentActivity()navigation-in-compose.kt
📝 Edit Code
👁 Kotlin Output
💡 Edit the Kotlin code, compile it, and inspect the output.
👁Expected Output
Screen ready🌎Real-World Uses
- 1Navigation in Compose appears in Android, backend, desktop, and multiplatform applications.
- 2Teams use this concept to reduce boilerplate while preserving type safety.
- 3It supports concise APIs that remain readable during maintenance.
- 4Understanding it improves debugging and code review quality.
- 5It helps Kotlin applications evolve without unnecessary mutation.
⚠Common Mistakes
- 1Using var when val communicates the intent better.
- 2Forcing nullable values instead of handling absence safely.
- 3Launching asynchronous work without lifecycle or cancellation rules.
- 4Creating large classes with mixed responsibilities.
- 5Using clever scope-function chains that hide control flow.
✅Best Practices
- 1Prefer val and immutable collections by default.
- 2Use null-safe operators and explicit domain types.
- 3Keep functions small and use named arguments where they improve clarity.
- 4Use structured concurrency for asynchronous work.
- 5Run formatting, static analysis, and automated tests.
💡Core idea
- 1Navigation in Compose should make intent visible through Kotlin types and expressions.
- 2Nullability is part of the type system.
- 3Concise syntax should improve clarity rather than hide behavior.
- 4A small runnable example verifies assumptions quickly.
💡How to apply it
- 1Start with immutable values and focused data classes.
- 2Model optional data with nullable types or sealed results.
- 3Keep Android and backend lifecycle boundaries explicit.
- 4Test normal, boundary, and failure paths.
💡Reliability checks
- 1Avoid !! except where an invariant is proven.
- 2Do not leak coroutine scopes or Android contexts.
- 3Keep blocking work away from UI and request threads.
- 4Validate external data before mapping it into domain objects.
💡Practice path
- 1Retype and run the example.
- 2Change one value and predict the output.
- 3Replace mutation with an immutable transformation.
- 4Extract reusable behavior into a focused function.
📋Quick Summary
- Navigation in Compose is a practical Kotlin concept.
- val and null-safety reduce common defects.
- Data classes and sealed types model domains clearly.
- Structured concurrency improves asynchronous reliability.
- Tests and static analysis support safe refactoring.
🎯Interview Questions
Q1. What is the purpose of Navigation in Compose?
Answer: It helps developers build lifecycle-aware Android interfaces while keeping Kotlin code concise and type-safe.
Q2. What is the difference between val and var?
Answer: val is a read-only reference, while var allows reassignment.
Q3. How does Kotlin null-safety work?
Answer: Nullable types use a question mark and require safe handling before non-null operations.
Q4. What is structured concurrency?
Answer: Structured concurrency ties asynchronous tasks to a scope so cancellation and lifetime are predictable.
Q5. Why use data classes?
Answer: Data classes provide value-oriented equality, copying, destructuring, and readable representations.
❓Quiz
Which habit best supports Navigation in Compose?