034 widget stack code quality

034: Widget Stack Code Quality Refactoring

Summary

Comprehensive code quality refactoring of the Widget Stack feature, addressing naming conventions, code duplication, data integrity bugs, type safety, and semantic confusion across 14 files.

Changes by Priority

CRITICAL: Data Integrity & Correctness

LauncherSettings.java

• Added ITEM_TYPE_WIDGET_STACK case to itemTypeToString() (was returning raw "12")
• Added isInsideCollection(int container) utility to replace fragile container > 0 heuristic

ModelUtils.java

• Split WIDGET_FILTER into two predicates:
  • APP_WIDGET_FILTER -- matches actual widgets only (not stacks)
  • WIDGET_OR_STACK_FILTER -- matches widgets AND stacks
• The old WIDGET_FILTER included stacks but every call site immediately added .filter(item -> item instanceof LauncherAppWidgetInfo) to exclude them

CacheDataUpdatedTask.java, PackageInstallStateChangedTask.java, PackageUpdatedTask.java, LoaderTask.java

• Switched to APP_WIDGET_FILTER and removed redundant instanceof LauncherAppWidgetInfo filter

BaseLauncherBinder.java

• Switched to WIDGET_OR_STACK_FILTER for item categorization (stacks should be categorized with widgets)

Workspace.java (removeItemsByMatcher)

• Added WidgetStackView handling in removeItemsByMatcher() for package uninstall
• Calls stackInfo.removeMatching(matcher) on matched children
• Removes entire stack if empty, otherwise calls rebuildFromStackInfo()

WidgetStackInfo.java (removeMatching)

• Added removeMatching(Predicate<ItemInfo>) method for package uninstall handling

WidgetStackView.java (rebuildFromStackInfo)

• Added rebuildFromStackInfo() to sync child views with model after mutations

WorkspaceItemProcessor.kt

• Replaced c.container > 0 with Favorites.isInsideCollection(c.container)

HIGH: Code Quality & Safety

WidgetStackView.java (full refactor)

• Renamed 18 private fields to AOSP m-prefix convention (e.g. widgetViews -> mWidgetViews, activeIndex -> mActiveIndex)
• Extracted accumulateFromProviderInfo() with ProviderInfoAccumulator interface -- five span/mode methods reduced to one-liners
• Extracted animateSnap() with SnapUpdateCallback interface -- snapToIndex() and snapBack() share ~30 lines of ValueAnimator setup
• Added mLongPressHelper.cancelLongPress() in onDetachedFromWindow() (was missing)

ItemInflater.kt

• Replaced unsafe child as LauncherAppWidgetInfo with safe cast + Log.e + continue

WidgetStackInfo.java (type safety)

• getActiveWidget() now uses instanceof pattern match instead of direct cast
• setActiveIndex() guards against empty contents to avoid Math.min(i, -1)

WidgetStackInfo.java (mutation/persistence separation)

• Replaced static assignWidgetToStack(stack, widget, rank, writer, isNew) with instance assignWidget(widget, rank) that only mutates fields
• DB persistence moved to callers in Launcher.java and Workspace.java

MEDIUM: Robustness & Polish

WidgetStackView.java (accessibility)

• Added onInitializeAccessibilityNodeInfo() with scroll forward/backward actions
• Added performAccessibilityAction() to navigate via snapToIndex()
• Added content description: "Widget %d of %d"

WidgetStackView.java (grid bounds)

• expandSpanIfNeeded() now clamps to InvariantDeviceProfile.numColumns/numRows

WidgetStackView.java (child persistence)

• Added updateChildWidgetSizes(context, spanX, spanY, writer) overload that persists child span changes to DB

AppWidgetResizeFrame.java

• Added content description on resize frame: "Widget stack with %d widgets"

LoaderCursor.java

• Extracted generic findOrMakeCollection(id, dataModel, type, factory) -- both findOrMakeFolder and findOrMakeWidgetStack are now one-liners

LOW: Nice-to-Have

WidgetStackInfo.java / WidgetStackView.java / Workspace.java

• Added MAX_STACK_SIZE = 6 constant enforced in add() and willAddToExistingWidgetStack()

WidgetStackView.java

• Renamed nextIndex to peekIndex in applySwipeTranslation() for consistency with snapBack()

New Resources

Resource	Value
widget_stack_page_description	"Widget %1$d of %2$d"

Documentation

• Added docs/widget-stack.md -- comprehensive architecture documentation covering data model, loading pipeline, view layer, drag-and-drop, resize, and package uninstall handling