Android: Synchronize window creation in QtEmbeddedDelegate

Qt window loading is initiated either when the QtView is attached
to its Android window, or when the Android QPA plugin has been loaded
and is ready, depending on the order. Since the window attachment
happens in the Android UI thread, and the Android QPA plugin callback
happens in Qt thread, add synchronized block to make sure the execution
stays ordered.

Fixes: QTBUG-122626
Pick-to: 6.7
Change-Id: Id476032f02aa8990432a02f62b6bf6237a17e7ac
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>

1 files changed, 23 insertions, 12 deletions

diff --git a/src/android/jar/src/org/qtproject/qt/android/QtEmbeddedDelegate.java b/src/android/jar/src/org/qtproject/qt/android/QtEmbeddedDelegate.java
index 975b26b915..74617706f9 100644
--- a/src/android/jar/src/org/qtproject/qt/android/QtEmbeddedDelegate.java
+++ b/src/android/jar/src/org/qtproject/qt/android/QtEmbeddedDelegate.java
@@ -26,6 +26,7 @@ class QtEmbeddedDelegate extends QtActivityDelegateBase implements QtNative.AppS
     private QtView m_view;
     private long m_rootWindowRef = 0L;
     private QtNative.ApplicationStateDetails m_stateDetails;
+    private boolean m_windowLoaded = false;
 
     private static native void createRootWindow(View rootView);
     static native void deleteWindow(long windowReference);
@@ -89,16 +90,18 @@ class QtEmbeddedDelegate extends QtActivityDelegateBase implements QtNative.AppS
 
     @Override
     public void onAppStateDetailsChanged(QtNative.ApplicationStateDetails details) {
-        m_stateDetails = details;
-        if (m_stateDetails.nativePluginIntegrationReady) {
-            QtNative.runAction(() -> {
-                DisplayMetrics metrics = Resources.getSystem().getDisplayMetrics();
-                QtDisplayManager.setApplicationDisplayMetrics(m_activity,
-                                                              metrics.widthPixels,
-                                                              metrics.heightPixels);
-              if (m_view != null)
-                  createRootWindow(m_view);
-            });
+        synchronized (this) {
+            m_stateDetails = details;
+            if (m_stateDetails.nativePluginIntegrationReady) {
+                QtNative.runAction(() -> {
+                    DisplayMetrics metrics = Resources.getSystem().getDisplayMetrics();
+                    QtDisplayManager.setApplicationDisplayMetrics(m_activity,
+                                                                  metrics.widthPixels,
+                                                                  metrics.heightPixels);
+
+                });
+                createRootWindow();
+            }
         }
     }
 
@@ -128,8 +131,9 @@ class QtEmbeddedDelegate extends QtActivityDelegateBase implements QtNative.AppS
 
     public void queueLoadWindow()
     {
-        if (m_stateDetails.nativePluginIntegrationReady)  {
-            createRootWindow(m_view);
+        synchronized (this) {
+            if (m_stateDetails.nativePluginIntegrationReady)
+                createRootWindow();
         }
     }
 
@@ -148,4 +152,11 @@ class QtEmbeddedDelegate extends QtActivityDelegateBase implements QtNative.AppS
             deleteWindow(m_rootWindowRef);
         m_rootWindowRef = 0L;
     }
+
+    private void createRootWindow() {
+        if (m_view != null && !m_windowLoaded) {
+            createRootWindow(m_view);
+            m_windowLoaded = true;
+        }
+    }
 }