Handle edge-to-edge when it's not enabled by gradle property

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/ReactActivityDelegate.java

@@ -138,9 +138,7 @@ public void onCreate(@Nullable Bundle savedInstanceState) {
           if (mActivity != null) {
             Window window = mActivity.getWindow();
             if (window != null) {
-              if (WindowUtilKt.isEdgeToEdgeFeatureFlagOn()) {
-                WindowUtilKt.enableEdgeToEdge(window);
-              }
+              WindowUtilKt.initEdgeToEdge(mActivity);
               if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O && isWideColorGamutEnabled()) {
                 window.setColorMode(ActivityInfo.COLOR_MODE_WIDE_COLOR_GAMUT);
               }

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/util/AndroidVersion.kt

@@ -21,10 +21,27 @@ internal object AndroidVersion {
   internal const val VERSION_CODE_VANILLA_ICE_CREAM: Int = 35
 
   /**
-   * This is the version code for Android 16 (SDK Level 36). Delete it once we bump up the default
-   * compile SDK version to 36.
+   * This is the version code for Android 16 (SDK Level 36). Internally at Meta this code is also
+   * compiled against SDK 34, so we need to retain this constant instead of using
+   * [Build.VERSION_CODES.BAKLAVA] directly.
+   */
+  internal const val VERSION_CODE_BAKLAVA: Int = 36
+
+  /**
+   * android.R.attr.windowOptOutEdgeToEdgeEnforcement added in API 35. Internally at Meta this code
+   * is compiled against an SDK that may not have this attribute defined.
+   * https://cs.android.com/android/platform/superproject/main/+/main:frameworks/base/core/res/res/values/public-final.xml;l=3848;drc=7fa5818fb7037c541807c3754882d98f6ea22d20
    */
-  private const val VERSION_CODE_BAKLAVA: Int = 36
+  internal const val ATTR_WINDOW_OPT_OUT_EDGE_TO_EDGE_ENFORCEMENT: Int = 0x0101069a
+
+  /**
+   * This method is used to check if the current device is running Android 15 (SDK Level 35) or
+   * higher and the app is targeting Android 15 (SDK Level 35) or higher.
+   */
+  @JvmStatic
+  internal fun isAtLeastTargetSdk35(context: Context): Boolean =
+      Build.VERSION.SDK_INT >= VERSION_CODE_VANILLA_ICE_CREAM &&
+          context.applicationInfo.targetSdkVersion >= VERSION_CODE_VANILLA_ICE_CREAM
 
   /**
    * This method is used to check if the current device is running Android 16 (SDK Level 36) or

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/view/WindowUtil.kt

@@ -7,6 +7,7 @@
 
 package com.facebook.react.views.view
 
+import android.app.Activity
 import android.graphics.Color
 import android.os.Build
 import android.view.Window
@@ -15,6 +16,7 @@ import androidx.core.view.ViewCompat
 import androidx.core.view.WindowCompat
 import androidx.core.view.WindowInsetsCompat
 import androidx.core.view.WindowInsetsControllerCompat
+import com.facebook.react.util.AndroidVersion
 import com.facebook.react.views.common.UiModeUtils
 
 // The light scrim color used in the platform API 29+
@@ -37,6 +39,32 @@ public fun setEdgeToEdgeFeatureFlagOn() {
   isEdgeToEdgeFeatureFlagOn = true
 }
 
+internal fun initEdgeToEdge(activity: Activity) {
+  // When the app targets SDK 35+, edge-to-edge may be enforced by the OS even if the
+  // feature flag wasn't explicitly set. In that case, turn the flag on to match.
+  if (AndroidVersion.isAtLeastTargetSdk35(activity)) {
+    if (Build.VERSION.SDK_INT >= AndroidVersion.VERSION_CODE_BAKLAVA) {
+      // The device is running Android 16+ (where edge-to-edge is always enforced)
+      isEdgeToEdgeFeatureFlagOn = true
+    } else {
+      val attributes = intArrayOf(AndroidVersion.ATTR_WINDOW_OPT_OUT_EDGE_TO_EDGE_ENFORCEMENT)
+      val typedArray = activity.theme.obtainStyledAttributes(attributes)
+
+      // The device is running Android 15 with / without opting out
+      isEdgeToEdgeFeatureFlagOn =
+          try {
+            !typedArray.getBoolean(0, false)
+          } finally {
+            typedArray.recycle()
+          }
+    }
+  }
+
+  if (isEdgeToEdgeFeatureFlagOn) {
+    activity.window.enableEdgeToEdge()
+  }
+}
+
 @Suppress("DEPRECATION")
 internal fun Window.setStatusBarTranslucency(isTranslucent: Boolean) {
   // If the status bar is translucent hook into the window insets calculations