Updated Android native app to better handle orientation changes

1 files changed, 26 insertions, 9 deletions

diff --git a/NativeApp/src/Android/AndroidAppBase.cpp b/NativeApp/src/Android/AndroidAppBase.cpp
index bc79470..3af8116 100644
--- a/NativeApp/src/Android/AndroidAppBase.cpp
+++ b/NativeApp/src/Android/AndroidAppBase.cpp
@@ -72,12 +72,6 @@ void AndroidAppBase::InitSensors()
 //
 void AndroidAppBase::DrawFrame()
 {
-    // APP_CMD_CONFIG_CHANGED event is generated seveal frames
-    // before the screen is actually resized. The only robust way
-    // to detect window resize is to check it very frame
-    if (CheckWindowSizeChanged())
-        WindowResize(window_width_, window_height_);
-
     float fFPS;
     if (monitor_.Update(fFPS))
     {
@@ -135,11 +129,34 @@ void AndroidAppBase::HandleCmd(struct android_app* app, int32_t cmd)
             break;
 
         case APP_CMD_CONFIG_CHANGED:
+        {
+            // This callback is not reliable for handling orientation changes. Depending on the
+            // device, it may be called before or after the surface has been actually resized.
+            break;
+        }
+
+        // Note that as of NDK r21b (21.1.6352462), APP_CMD_WINDOW_RESIZED event is never generated
+        // by android_native_app_glue.
+        // Also note that modifying android_native_app_glue to handle onNativeWindowResized
+        // callback (as suggested in https://android-developers.googleblog.com/2020/02/handling-device-orientation-efficiently.html)
+        // does not work either - the callback is only called once after the window has been created.
         case APP_CMD_WINDOW_RESIZED:
-            // This does not work as the screen resizes few frames
-            // after the event has been received
-            // eng->WindowResize(0,0);
+        {
+            auto new_window_width  = ANativeWindow_getWidth(app->window);
+            auto new_window_height = ANativeWindow_getHeight(app->window);
+            eng->WindowResize(new_window_width, new_window_height);
             break;
+        }
+
+        // Note that as of NDK r21b (21.1.6352462), APP_CMD_CONTENT_RECT_CHANGED event is never
+        // generated by android_native_app_glue
+        case APP_CMD_CONTENT_RECT_CHANGED:
+        {
+            auto new_window_width  = app->contentRect.right - app->contentRect.left;
+            auto new_window_height = app->contentRect.bottom - app->contentRect.top;
+            eng->WindowResize(new_window_width, new_window_height);
+            break;
+        }
 
         case APP_CMD_TERM_WINDOW:
             // The window is being hidden or closed, clean it up.