Fix: don't request MediaProjection permission for text-only WebView models

sendMessageFromWebView checked GenerativeAiViewModelFactory.getCurrentModel()
.supportsScreenshot directly, which always reports true for ONLINE_MODEL (the
placeholder used for every JS-only model selected from the WebView dropdown).
This caused a MediaProjection permission prompt before sending a message even
when a text-only model (e.g. a Groq/Cerebras text-only model) was selected.

Extracted the existing, correct capability-resolution logic from
ScreenOperatorAccessibilityService.currentModelSupportsScreenshot() into a
shared util/ActiveModelCapabilities.kt so both the accessibility service and
MainActivity.sendMessageFromWebView resolve the model's real screenshot
support the same way (custom JSON model -> JS-only WebView model via the
persisted js_only_supports_screenshot flag -> native model enum).

Author: claude

app/src/main/kotlin/com/google/ai/sample/MainActivity.kt

@@ -69,6 +69,7 @@ import com.android.billingclient.api.PendingPurchasesParams
 import com.google.ai.sample.feature.multimodal.PhotoReasoningViewModel
 import com.google.ai.sample.GenerativeAiViewModelFactory
 import com.google.ai.sample.ui.theme.GenerativeAISample
+import com.google.ai.sample.util.ActiveModelCapabilities
 import com.google.ai.sample.util.BroadcastReceiverCompat
 import com.google.ai.sample.util.NotificationUtil
 import com.google.ai.sample.util.TermuxExecutionModePreferences
@@ -1396,9 +1397,17 @@ class MainActivity : ComponentActivity() {
         // Mirror the native send-button logic: ask for MediaProjection permission before sending
         // when the active model supports screenshots, unless it is the Human Expert model (which
         // manages its own WebRTC-based projection separately).
+        // Use ActiveModelCapabilities instead of GenerativeAiViewModelFactory.getCurrentModel()
+        // .supportsScreenshot directly: for JS-only online models selected from the WebView
+        // dropdown (the normal case here), currentModel stays ONLINE_MODEL, which always
+        // reports supportsScreenshot=true - so a text-only WebView model (e.g. a Groq/Cerebras
+        // text-only model) would otherwise incorrectly trigger a MediaProjection permission
+        // request before every send. ActiveModelCapabilities resolves the model's real
+        // capability from the WebView-persisted "js_only_supports_screenshot" flag instead.
         val currentModel = GenerativeAiViewModelFactory.getCurrentModel()
         val modelName = currentModel.name
-        val requiresScreenCapturePermission = currentModel.supportsScreenshot && modelName != "HUMAN_EXPERT"
+        val requiresScreenCapturePermission =
+            ActiveModelCapabilities.currentModelSupportsScreenshot(this) && modelName != "HUMAN_EXPERT"
         if (!_isMediaProjectionPermissionGranted.value && requiresScreenCapturePermission) {
             Log.d(TAG, "sendMessageFromWebView: MediaProjection not yet granted. Requesting permission first.")
             requestMediaProjectionPermission {

app/src/main/kotlin/com/google/ai/sample/ScreenOperatorAccessibilityService.kt

@@ -25,6 +25,7 @@ import android.view.KeyEvent
 import android.view.accessibility.AccessibilityEvent
 import android.view.accessibility.AccessibilityNodeInfo
 import android.widget.Toast
+import com.google.ai.sample.util.ActiveModelCapabilities
 import com.google.ai.sample.util.AppNamePackageMapper
 import com.google.ai.sample.util.AppOpenFeedbackPreferences
 import com.google.ai.sample.util.Command
@@ -515,33 +516,8 @@ class ScreenOperatorAccessibilityService : AccessibilityService() {
      * for a text-only model: Command.Wait's toast, the delayed-screenshot toast, and the
      * actual capture/MediaProjection-request decision in executeTakeScreenshotCommand.
      */
-    private fun currentModelSupportsScreenshot(): Boolean {
-        com.google.ai.sample.util.CustomModelRegistry.getActiveModel()?.let { customModel ->
-            return customModel.supportsScreenshot
-        }
-
-        val currentModel = GenerativeAiViewModelFactory.getCurrentModel()
-        val jsModelPrefs = applicationContext.getSharedPreferences("js_model_prefs", android.content.Context.MODE_PRIVATE)
-        val jsOnlyModelId = jsModelPrefs.getString("js_only_model_id", null)
-
-        // JS-only online models (the normal WebView model dropdown) are a third, separate
-        // case: they are not in CustomModelRegistry, and ModelOption.ONLINE_MODEL always
-        // reports supportsScreenshot=true. Their real capability is persisted by the WebView
-        // on model selection (dispatch("setJsOnlyModelSupportsScreenshot", ...)) - the same
-        // flag PhotoReasoningViewModel already reads to decide whether to attach the image to
-        // the outgoing payload. jsOnlyModelId being non-null is itself the reliable signal
-        // that a JS-only model is active (it is cleared whenever a custom or native built-in
-        // model is selected instead - see WebViewBridge.setSelectedModel) - it is checked on
-        // its own, without also requiring currentModel == ONLINE_MODEL, because currentModel
-        // is only updated by native built-in model selections and can otherwise still hold a
-        // stale value (e.g. a previously selected offline model) while a JS-only model is the
-        // one actually active.
-        if (jsOnlyModelId != null) {
-            return jsModelPrefs.getBoolean("js_only_supports_screenshot", true)
-        }
-
-        return currentModel.supportsScreenshot
-    }
+    private fun currentModelSupportsScreenshot(): Boolean =
+        ActiveModelCapabilities.currentModelSupportsScreenshot(applicationContext)
 
     private fun executeTakeScreenshotCommand(): Boolean {
         val delayMillis = pendingScreenshotDelayMillis

app/src/main/kotlin/com/google/ai/sample/util/ActiveModelCapabilities.kt

@@ -0,0 +1,49 @@
+package com.google.ai.sample.util
+
+import android.content.Context
+import com.google.ai.sample.GenerativeAiViewModelFactory
+
+/**
+ * Resolves whether the currently active model (whichever of the three model categories -
+ * custom JSON-defined model, JS-only online model, or native built-in model/offline model -
+ * is active) actually supports screenshots/vision input.
+ *
+ * This is the single source of truth used everywhere a screenshot-related decision must
+ * reflect the model's *real* capability rather than the native [GenerativeAiViewModelFactory]
+ * model enum, which always reports `supportsScreenshot = true` for `ONLINE_MODEL` (the
+ * placeholder used for every JS-only model selected from the WebView dropdown). Used for:
+ * the actual capture/MediaProjection-request decision in
+ * `ScreenOperatorAccessibilityService.executeTakeScreenshotCommand`, its related toasts, and
+ * the pre-send MediaProjection permission check in `MainActivity.sendMessageFromWebView`.
+ */
+object ActiveModelCapabilities {
+
+    fun currentModelSupportsScreenshot(context: Context): Boolean {
+        CustomModelRegistry.getActiveModel()?.let { customModel ->
+            return customModel.supportsScreenshot
+        }
+
+        val currentModel = GenerativeAiViewModelFactory.getCurrentModel()
+        val jsModelPrefs = context.applicationContext
+            .getSharedPreferences("js_model_prefs", Context.MODE_PRIVATE)
+        val jsOnlyModelId = jsModelPrefs.getString("js_only_model_id", null)
+
+        // JS-only online models (the normal WebView model dropdown) are a third, separate
+        // case: they are not in CustomModelRegistry, and ModelOption.ONLINE_MODEL always
+        // reports supportsScreenshot=true. Their real capability is persisted by the WebView
+        // on model selection (dispatch("setJsOnlyModelSupportsScreenshot", ...)) - the same
+        // flag PhotoReasoningViewModel already reads to decide whether to attach the image to
+        // the outgoing payload. jsOnlyModelId being non-null is itself the reliable signal
+        // that a JS-only model is active (it is cleared whenever a custom or native built-in
+        // model is selected instead - see WebViewBridge.setSelectedModel) - it is checked on
+        // its own, without also requiring currentModel == ONLINE_MODEL, because currentModel
+        // is only updated by native built-in model selections and can otherwise still hold a
+        // stale value (e.g. a previously selected offline model) while a JS-only model is the
+        // one actually active.
+        if (jsOnlyModelId != null) {
+            return jsModelPrefs.getBoolean("js_only_supports_screenshot", true)
+        }
+
+        return currentModel.supportsScreenshot
+    }
+}