Android Viewsystem Foundations

Android ViewSystem Foundations

When To Use

• Use this skill when the request is about: xml layout android issue, fragment lifecycle android, constraintlayout cleanup.
• Primary outcome: Handle XML layouts, ConstraintLayout, Fragments, ViewBinding, DataBinding, and classic Android UI lifecycle patterns.
• Reach for this skill when the main surface is XML, Fragment, RecyclerView, or binding lifecycle work rather than Compose-first UI.
• Handoff skills when the scope expands:
• android-compose-xml-interoperability
• android-testing-ui

Workflow

1. Identify whether the target surface is Fragment, Activity, custom view, RecyclerView, or a mixed Compose/View interoperability screen.
2. Anchor ownership correctly: view bindings to the view lifecycle, adapters to explicit item models, and navigation/transactions outside leaf views.
3. Fix layout and rendering issues with classic View tools first: ConstraintLayout, RecyclerView diffing, window insets, and binding-safe updates.
4. Exercise Fragment recreation, long text, font scaling, RTL, and process-lifecycle edges before considering the change complete.
5. Hand off Compose interoperability or UI test depth only after the View-system ownership model is stable.

Guardrails

• Optimize for stable state and predictable rendering before adding animation or abstraction.
• Respect accessibility semantics, contrast, focus order, and touch target guidance by default.
• Do not mix Compose and View system ownership without an explicit interoperability boundary.
• Prefer measured performance work over premature micro-optimizations.
• Clear ViewBinding references when the Fragment view is destroyed; do not keep view references alive past the view lifecycle.

Anti-Patterns

• Embedding navigation or business logic directly in leaf UI components.
• Using fixed dimensions that break on localization or dynamic text.
• Ignoring semantics and announcing only visual changes.
• Porting XML patterns directly into Compose without adapting the mental model.
• Holding Fragment view state in stale bindings, view references, or adapters across view recreation.

Examples

Happy path

• Scenario: Refine the XML OrbitTasks screen with ViewBinding and explicit fragment-safe patterns.
• Command: cd examples/orbittasks-xml && ./gradlew :app:testDebugUnitTest

Edge case

• Scenario: Handle configuration changes, view lifecycle, and long content in classic layouts.
• Command: cd examples/orbittasks-xml && ./gradlew :app:connectedDebugAndroidTest

Failure recovery

• Scenario: Prevent XML or Fragment requests from being routed to Compose-first skills.
• Command: python3 scripts/eval_triggers.py --skill android-viewsystem-foundations

Done Checklist

• The implementation path is explicit, minimal, and tied to the right Android surface.
• Relevant example commands and benchmark prompts have been exercised or updated.
• Handoffs to adjacent skills are documented when the request crosses boundaries.
• Official references cover the chosen pattern and the main migration or troubleshooting path.

Official References

• https://developer.android.com/guide/fragments
• https://developer.android.com/topic/libraries/view-binding
• https://developer.android.com/training/constraint-layout
• https://developer.android.com/topic/libraries/data-binding