fix: handle application/octet-stream for .gpx on Android 16 (Google Files)

Google Files uses application/octet-stream for .gpx because Android 16's
MimeTypeMap has no entry for that extension. The ExternalStorageProvider
content URI encodes the full file path, so pathSuffix=".gpx" keeps the
ACTION_VIEW filter targeted without matching all binary files.

ACTION_SEND (share sheet) filters added for typed MIME variants; code now
handles both actions — EXTRA_STREAM for SEND, intent.data for VIEW.

For octet-stream and generic XML types, OpenableColumns.DISPLAY_NAME is
checked before parsing (uri.lastPathSegment is an opaque ID for content
URIs, not the filename). All decisions logged to NavLogger.

https://claude.ai/code/session_01DNjbYxiC1cco83dArNGW3G

2 files changed, 56 insertions, 11 deletions

diff --git a/android-app/app/src/main/AndroidManifest.xml b/android-app/app/src/main/AndroidManifest.xml
index 196932d..a10d503 100644
--- a/android-app/app/src/main/AndroidManifest.xml
+++ b/android-app/app/src/main/AndroidManifest.xml
@@ -46,9 +46,7 @@
                 <category android:name="android.intent.category.DEFAULT" />
                 <data android:mimeType="application/gpx" />
             </intent-filter>
-            <!-- GPX as XML — Android's MimeTypeMap often maps .gpx to text/xml because
-                 application/gpx+xml isn't in the base system database. Code checks the
-                 display name before parsing. -->
+            <!-- Generic XML — some file managers use this for .gpx; code checks display name -->
             <intent-filter>
                 <action android:name="android.intent.action.VIEW" />
                 <category android:name="android.intent.category.DEFAULT" />
@@ -59,6 +57,40 @@
                 <category android:name="android.intent.category.DEFAULT" />
                 <data android:mimeType="application/xml" />
             </intent-filter>
+            <!-- Google Files on Android 16 sends application/octet-stream for .gpx because
+                 MimeTypeMap has no entry for that extension. The ExternalStorageProvider URI
+                 encodes the full file path, so pathSuffix=".gpx" keeps this targeted.
+                 Code double-checks via OpenableColumns.DISPLAY_NAME before parsing. -->
+            <intent-filter>
+                <action android:name="android.intent.action.VIEW" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:scheme="content" android:mimeType="application/octet-stream"
+                    android:pathSuffix=".gpx" />
+            </intent-filter>
+
+            <!-- Share-sheet filters (ACTION_SEND): file URI is in EXTRA_STREAM, not
+                 intent data, so pathSuffix can't help — these cover apps that type .gpx
+                 correctly. Code checks display name for the XML variants. -->
+            <intent-filter>
+                <action android:name="android.intent.action.SEND" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="application/gpx+xml" />
+            </intent-filter>
+            <intent-filter>
+                <action android:name="android.intent.action.SEND" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="application/gpx" />
+            </intent-filter>
+            <intent-filter>
+                <action android:name="android.intent.action.SEND" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="text/xml" />
+            </intent-filter>
+            <intent-filter>
+                <action android:name="android.intent.action.SEND" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="application/xml" />
+            </intent-filter>
         </activity>
     </application>
 </manifest>
diff --git a/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt b/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt
index 07adb35..bfa285d 100644
--- a/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt
+++ b/android-app/app/src/main/kotlin/org/terst/nav/MainActivity.kt
@@ -140,33 +140,46 @@ class MainActivity : AppCompatActivity(), SafetyFragment.SafetyListener {
     }
 
     private fun handleIncomingGpx(intent: Intent?) {
-        if (intent?.action != Intent.ACTION_VIEW) return
-        val uri = intent.data ?: return
+        val action = intent?.action ?: return
+        // Pull the URI from the right place depending on whether this is a direct open
+        // (ACTION_VIEW: URI in intent.data) or a share-sheet send (ACTION_SEND: URI in EXTRA_STREAM).
+        val uri = when (action) {
+            Intent.ACTION_VIEW -> intent.data
+            Intent.ACTION_SEND -> intent.getParcelableExtra(Intent.EXTRA_STREAM, android.net.Uri::class.java)
+            else -> null
+        } ?: return
+
         val mime = intent.type ?: contentResolver.getType(uri) ?: ""
         when {
-            // Known GPX MIME types — proceed immediately.
             mime.contains("gpx", ignoreCase = true) -> Unit
-            // Generic XML MIME (text/xml, application/xml): the Android system MimeTypeMap
-            // often lacks application/gpx+xml for .gpx, so file managers fall back to an
-            // XML type. Verify the display name before parsing to avoid opening random XML.
-            mime.contains("xml", ignoreCase = true) -> {
+            // Generic XML or octet-stream: confirm it's actually a .gpx file by display name
+            // before parsing. For content URIs from Google Files, lastPathSegment is an opaque
+            // ID — OpenableColumns.DISPLAY_NAME is the reliable source of the actual filename.
+            mime.contains("xml", ignoreCase = true) || mime == "application/octet-stream" -> {
                 val displayName = contentResolver.query(
                     uri, arrayOf(OpenableColumns.DISPLAY_NAME), null, null, null
                 )?.use { c -> if (c.moveToFirst()) c.getString(0) else null }
-                if (displayName?.lowercase()?.endsWith(".gpx") != true) return
+                if (displayName?.lowercase()?.endsWith(".gpx") != true) {
+                    NavLogger.i("track", "handleIncomingGpx: skipping non-gpx file (mime=$mime displayName=$displayName)")
+                    return
+                }
             }
             else -> return
         }
+
+        NavLogger.i("track", "handleIncomingGpx: action=$action mime=$mime uri=$uri")
         lifecycleScope.launch {
             runCatching {
                 val points = withContext(Dispatchers.IO) {
                     contentResolver.openInputStream(uri)?.use { GpxParser.parse(it) } ?: emptyList()
                 }
+                NavLogger.i("track", "handleIncomingGpx: parsed ${points.size} points")
                 if (points.isNotEmpty()) {
                     viewModel.addImportedTrack(points)
                     showOverlay(SavedTracksFragment())
                 }
             }.onFailure { e ->
+                NavLogger.e("track", "handleIncomingGpx: failed: ${e.javaClass.simpleName}: ${e.message}")
                 Log.e("MainActivity", "Failed to open GPX: ${e.message}")
             }
         }