Emit paletteChanged and send ApplicationPaletteChange on theme change

Fixes: QTBUG-72575
Change-Id: I407e081295a456a7bdd36de91ca5bbf74bba6078
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

2 files changed, 13 insertions, 0 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index f4e2dda05a..a63e172461 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -3983,6 +3983,9 @@ void QGuiApplicationPrivate::notifyThemeChanged()
         !QCoreApplication::testAttribute(Qt::AA_SetPalette)) {
         clearPalette();
         initPalette();
+        emit qGuiApp->paletteChanged(*app_pal);
+        if (is_app_running && !is_app_closing)
+            sendApplicationPaletteChange();
     }
     if (!(applicationResourceFlags & ApplicationFontExplicitlySet)) {
         QMutexLocker locker(&applicationFontMutex);
@@ -3991,6 +3994,15 @@ void QGuiApplicationPrivate::notifyThemeChanged()
     }
 }
 
+void QGuiApplicationPrivate::sendApplicationPaletteChange(bool toAllWidgets, const char *className)
+{
+    Q_UNUSED(toAllWidgets)
+    Q_UNUSED(className)
+
+    QEvent event(QEvent::ApplicationPaletteChange);
+    QGuiApplication::sendEvent(QGuiApplication::instance(), &event);
+}
+
 #if QT_CONFIG(draganddrop)
 void QGuiApplicationPrivate::notifyDragStarted(const QDrag *drag)
 {
diff --git a/src/gui/kernel/qguiapplication_p.h b/src/gui/kernel/qguiapplication_p.h
index 79c1a1c820..042a36c31f 100644
--- a/src/gui/kernel/qguiapplication_p.h
+++ b/src/gui/kernel/qguiapplication_p.h
@@ -313,6 +313,7 @@ public:
 
 protected:
     virtual void notifyThemeChanged();
+    virtual void sendApplicationPaletteChange(bool toAllWidgets = false, const char *className = nullptr);
     bool tryCloseRemainingWindows(QWindowList processedWindows);
 #if QT_CONFIG(draganddrop)
     virtual void notifyDragStarted(const QDrag *);