android-legacy-state

name	android-legacy-state
description	Integrate ViewModel state with XML Views using Coroutines and Lifecycle on Android. Use when managing state with repeatOnLifecycle or lifecycle-aware coroutines in Fragment/Activity; defer Compose state and generic Flow design to their specific skills.
metadata	{"triggers":{"files":["**/*Fragment.kt","**/*Activity.kt"],"keywords":["repeatOnLifecycle","launchWhenStarted"]}}

Android Legacy State Standards

Priority: P1 (HIGH)

Implementation Guidelines

Flow Consumption

• Rule: ALWAYS use repeatOnLifecycle(Lifecycle.State.STARTED) to collect flows in Views.
• Why: Prevents crashes (collecting while view destroyed) and saves resources (stops collecting in background).

LiveData vs Flow

• New Code: Use StateFlow exclusively.
• Legacy: If using LiveData, observe with viewLifecycleOwner (Fragment), NOT this.

Anti-Patterns

• No launchWhenStarted/Resumed: Deprecated. Use repeatOnLifecycle instead.
• No observe(this) in Fragments: Use viewLifecycleOwner to prevent lifecycle leaks.

References

• Flow Consumption Template