Patch the activity the launcher alias targets, not the first MAIN filter

Second review follow-up: with several activities (e.g. a splash activity ahead
of the game), the alias fallback now prefers the real activity named by the
alias's android:targetActivity. Reads targetActivity by resource id, updates
the error text and docs/vr-apks.md.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

ui/frame_android.py

@@ -322,7 +322,7 @@ def patch(src, dst, add=None):
             original = frame_apk._read(z, 'AndroidManifest.xml', frame_apk.MAX_MANIFEST)
         manifest = add_launcher_category(original) if info['repairable'] else original
         if not info['launchable'] and not info['repairable']:
-            raise FrameError('APK has no MAIN/LAUNCHER or patchable VR activity')
+            raise FrameError('APK has no MAIN/LAUNCHER activity that Frame Control can patch')
         repack(src, dst, replace={'AndroidManifest.xml': manifest}, add=add)
         result = apk_info(dst)
         result.pop('icon_png', None)

ui/frame_apk.py

@@ -10,7 +10,8 @@ import zipfile
 
 # android: attribute resource ids; names can be stripped by shrinkers, ids can't.
 ATTR = {0x01010001: 'label', 0x01010002: 'icon', 0x01010003: 'name',
-        0x01010024: 'value', 0x0101021b: 'versionCode', 0x0101021c: 'versionName', 0x0101020c: 'minSdkVersion'}
+        0x01010024: 'value', 0x0101021b: 'versionCode', 0x0101021c: 'versionName', 0x0101020c: 'minSdkVersion',
+        0x01010202: 'targetActivity'}
 T_REF, T_STRING, T_INT_DEC, T_INT_HEX = 0x01, 0x03, 0x10, 0x11
 # APKs can come from websites (install links), so nothing read from one may be
 # unbounded. zipfile stops at a member's declared size, so checking it is enough.

ui/frame_apk_vr.py

@@ -10,13 +10,18 @@ VR = {'com.oculus.intent.category.VR', 'org.khronos.openxr.intent.category.IMMER
 def inspect(data):
     elements = iter(frame_apk.manifest_elements(data))
     stack, filters, samsung = [], [], False
-    current = None
+    current, owner, package = None, None, ''
     for kind, hs, off, size in frame_apk._chunks(data, 8, len(data)):
         if kind == 0x0102:
             tag, attrs = next(elements)
             value = attrs.get('name', (None, None, None))[2]
+            if tag == 'manifest':
+                package = attrs.get('package', (None, None, None))[2] or ''
+            if tag in ('activity', 'activity-alias'):
+                owner = attrs.get('targetActivity', (None, None, None))[2] if tag == 'activity-alias' else value
+                owner = package + owner if owner and owner.startswith('.') else owner
             if tag == 'intent-filter' and stack and stack[-1] in ('activity', 'activity-alias'):
-                current = {'actions': set(), 'categories': set(), 'templates': [], 'alias': stack[-1] == 'activity-alias'}
+                current = {'actions': set(), 'categories': set(), 'templates': [], 'alias': stack[-1] == 'activity-alias', 'activity': owner}
             if current is not None and stack and stack[-1] == 'intent-filter':
                 if tag == 'action':
                     current['actions'].add(value)
@@ -38,7 +43,9 @@ def inspect(data):
     real = [f for f in mains if not f['alias']]
     targets = [f for f in real if VR & f['categories']]
     if not targets and any(LAUNCHER in f['categories'] or VR & f['categories'] for f in mains if f['alias']):
+        aimed = {f['activity'] for f in mains if f['alias'] and (LAUNCHER in f['categories'] or VR & f['categories'])}
         targets = [f for f in real if f['templates']]  # the patch copies an existing <category>
+        targets = [f for f in targets if f['activity'] in aimed] or targets
     launchable = any(LAUNCHER in f['categories'] for f in real)
     return {'launchable': launchable, 'repairable': not launchable and bool(targets),
             'vr_activity': bool(vr_filters), 'vr': bool(vr_filters) or samsung}, targets