android-legacy-state

$npx mdskill add HoangNguyen0403/agent-skills-standard/android-legacy-state

Integrate ViewModel state with Views using Coroutines and Lifecycle on Android for Fragment/Activity

  • Ensures LiveData is observed with viewLifecycleOwner to prevent lifecycle leaks.
  • Uses StateFlow exclusively in new code, and observes LiveData with viewLifecycleOwner in legacy code.
  • Prevents crashes by collecting flows only when the View is started using repeatOnLifecycle(Lifecycle.State.STARTED).
  • Delivers state updates directly to Views via Coroutines and Lifecycle-aware coroutines for efficient state management.

SKILL.md

.github/skills/android-legacy-stateView on GitHub ↗
---
name: android-legacy-state
description: Integrate ViewModel state with Views using Coroutines and Lifecycle on Android. Use when managing state with repeatOnLifecycle or lifecycle-aware coroutines in Fragment/Activity.
metadata:
  triggers:
    files:
    - '**/*Fragment.kt'
    - '**/*Activity.kt'
    keywords:
    - repeatOnLifecycle
    - launchWhenStarted
---
# Android Legacy State Standards

## **Priority: P1**

## 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](references/implementation.md)

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