SDL: Android: restore the system bars when leaving fullscreen on API 30+

From 8408a664e2ab22585652b7c4f2197c8050ebffe7 Mon Sep 17 00:00:00 2001
From: klirktag <[EMAIL REDACTED]>
Date: Wed, 15 Jul 2026 00:41:49 +0200
Subject: [PATCH] Android: restore the system bars when leaving fullscreen on
 API 30+

My old PR #15867 switched the fullscreen path to WindowInsetsController.hide() for API 30+, because the legacy setSystemUiVisibility() flags are ignored on API 30+.

The leaving fullscreen path was left untouched: it still calls setSystemUiVisibility(SYSTEM_UI_FLAG_VISIBLE), which is equally ignored on API 30+.

As a result, once fullscreen had hidden the status/navigation bars, they never came back when returning to windowed mode.
---
 .../main/java/org/libsdl/app/SDLActivity.java | 20 +++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/android-project/app/src/main/java/org/libsdl/app/SDLActivity.java b/android-project/app/src/main/java/org/libsdl/app/SDLActivity.java
index 197edc4007cd9..ed1ffd509143a 100644
--- a/android-project/app/src/main/java/org/libsdl/app/SDLActivity.java
+++ b/android-project/app/src/main/java/org/libsdl/app/SDLActivity.java
@@ -1012,10 +1012,22 @@ public void handleMessage(Message msg) {
                             }
                             SDLActivity.mFullscreenModeActive = true;
                         } else {
-                            int flags = View.SYSTEM_UI_FLAG_LAYOUT_STABLE | View.SYSTEM_UI_FLAG_VISIBLE;
-                            window.getDecorView().setSystemUiVisibility(flags);
-                            window.addFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
-                            window.clearFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
+                            if (Build.VERSION.SDK_INT >= 30 /* Android 11 (R) */) {
+                                // The legacy setSystemUiVisibility() flags are ignored on
+                                // API 30+, so the bars hidden by the modern enter path above
+                                // would never come back. Restore them via WindowInsetsController.
+                                final WindowInsetsController controller = window.getInsetsController();
+                                if (controller != null) {
+                                    controller.setSystemBarsBehavior(
+                                            WindowInsetsController.BEHAVIOR_DEFAULT);
+                                    controller.show(WindowInsets.Type.systemBars());
+                                }
+                            } else {
+                                int flags = View.SYSTEM_UI_FLAG_LAYOUT_STABLE | View.SYSTEM_UI_FLAG_VISIBLE;
+                                window.getDecorView().setSystemUiVisibility(flags);
+                                window.addFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
+                                window.clearFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
+                            }
                             SDLActivity.mFullscreenModeActive = false;
                         }
                         if (Build.VERSION.SDK_INT >= 30 /* Android 11 (R) */) {