android-fold-adapter

中文环境要求

本技能运行在中文环境下，请遵循以下约定：

• 面向用户的回复、注释、提示信息必须使用中文
• AI 内部处理过程可以使用英文
• 所有生成的文件必须使用 UTF-8 编码

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Android Foldable Screen Adapter

Fix issues caused by foldable screen fold/unfold events. These events trigger configuration changes (screenSize, smallestScreenSize, screenLayout) that destroy and recreate Activities unless handled.

Self-Update Mechanism

This skill supports automatic updates. When solving a new foldable screen issue:

1. Apply the fix using the patterns below
2. If the fix involves a new pattern not covered here, update this SKILL.md file
3. Add the new issue to "Known Issues Archive" section
4. Run /android-dev-tools:update-remote-plugins to sync changes

Diagnosis Workflow

Step 1: Identify the Affected Activity

1. Determine which Activity exhibits the issue.
2. Read the AndroidManifest.xml entry for that Activity.
3. Check whether android:configChanges includes foldable-relevant values:
   • screenSize
   • smallestScreenSize
   • screenLayout
4. Compare with other Activities in the same project that already work on foldable screens — use them as reference for the correct configChanges value.

Step 2: Analyze State Loss

If the Activity lacks configChanges, it gets destroyed and recreated on fold/unfold. Check for:

• UI visibility state loss: Does onCreate reset visibility of containers based on intent.action without checking savedInstanceState? This causes search results, loaded content, or navigation state to disappear.
• Data field reset: Are fields like search keywords, page numbers, or filter selections reset to defaults on recreation?
• Fragment reference invalidation: If the Activity holds WeakReference or SparseArray references to Fragments (common with ViewPager2 + FragmentStateAdapter), these references become stale after recreation because FragmentStateAdapter restores Fragments via FragmentManager without calling createFragment().

Step 3: Check Click/Event Handler Failures

After Activity recreation:

• Fragment references in the Activity may be empty → forEach on the reference collection does nothing → button clicks appear to have no effect.
• The Fragment itself may have a lock mechanism (e.g., searchLock) that prevents re-entry but never gets reset.
• lifecycleScope coroutines launched before destruction may have been cancelled, and new ones aren't started.

Fix Patterns

Pattern A: Prevent Recreation via Manifest (Primary Fix)

Add android:configChanges to the Activity in AndroidManifest.xml:

<activity
    android:name=".ui.YourActivity"
    android:configChanges="orientation|keyboardHidden|screenSize|smallestScreenSize|density|screenLayout"
    ... />

Copy the exact configChanges value from other Activities in the same project that already handle foldable screens (e.g., HomeActivity, WebActivity).

Pattern B: Save and Restore State (Defensive Fallback)

Even with Pattern A, add state saving as a fallback (system can still kill the Activity in low-memory situations):

override fun onSaveInstanceState(outState: Bundle) {
    super.onSaveInstanceState(outState)
    outState.putString(KEY_SEARCH_CONTENT, contentSearch)
    outState.putBoolean(KEY_HAS_RESULTS, binding.container.visibility == View.VISIBLE)
}

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)

    val restored = savedInstanceState?.getBoolean(KEY_HAS_RESULTS, false) == true
    if (restored) {
        // Restore UI state from savedInstanceState
        contentSearch = savedInstanceState?.getString(KEY_SEARCH_CONTENT, "") ?: ""
        binding.container.visibility = View.VISIBLE
        // ...
    } else {
        // Normal intent-based initialization
    }
}

Pattern C: Fix Fragment References (Critical for ViewPager2)

Never rely on a manually maintained SparseArray<WeakReference<Fragment>> to find Fragments after recreation. Use FragmentManager instead:

// BAD: stale after recreation
fragments.forEach { key, value ->
    value.get()?.doSomething()
}

// GOOD: always finds current Fragment instances
supportFragmentManager.fragments
    .filterIsInstance<YourFragment>()
    .forEach { it.doSomething() }

For FragmentStateAdapter hosted in Activity, Fragments are in supportFragmentManager. For FragmentStateAdapter hosted in Fragment, Fragments are in that Fragment's childFragmentManager.

Checklist

Before marking the fix complete, verify:

• AndroidManifest.xml: Target Activity has configChanges with screenSize|smallestScreenSize|screenLayout
• onSaveInstanceState: Key UI state and data fields are saved
• onCreate: savedInstanceState is checked before intent.action to restore state
• Fragment references: Use FragmentManager.fragments instead of manual collections
• No stale locks: Verify that locks (e.g., searchLock) are properly reset on recreation
• Build passes: ./gradlew :module:assembleDebug

Known Issues Archive

Issue #1: Search Page — Fold/Unfold Causes Content Loss + Button Unresponsive

Symptoms: After searching on the search page, folding/unfolding the screen causes search results to disappear. After re-searching, subsequent search button clicks have no effect.

Root Cause: SearchActivity lacked configChanges → Activity recreated → onCreate hid the results container → fragments SparseArray emptied → search() method's forEach iterated over nothing.

Fix Applied: Pattern A + B + C (all three). Files changed:

• AndroidManifest.xml — added configChanges
• SearchActivity.kt — added onSaveInstanceState/restore + replaced fragments.forEach with supportFragmentManager.fragments.filterIsInstance<SearchFragment>()

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Issue #2: Desktop Widget — pm clear After Fold/Unfold Shows "Unable To Load Widget"

Symptoms: After placing the widget on the launcher, running adb shell pm clear com.vertu.personalizationwidget, then folding or unfolding the device causes the launcher widget to show "无法加载微件" and become non-clickable.

Root Cause: The widget provider rebuilt fallback data after pm clear, but logo rendering still relied on FileProvider URIs pointing to app-private files under files/logos. During launcher host rebind on fold/unfold, those file-backed URIs could become stale or invalid after the app data clear, causing the host to fail while applying RemoteViews.

Fix Applied: Restore default widget state synchronously after pm clear, ensure built-in logo assets are recreated if missing, and replace setImageViewUri(...) with setImageViewBitmap(...) so widget rendering no longer depends on app-private file URIs surviving host-side rebinds. Files changed:

• WidgetEngraving/src/main/java/com/vertu/personalizationwidget/EngravingAppWidgetProvider.kt — persist fallback widget entity, restore built-in logos, replace URI-based logo rendering with bitmap-based rendering

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