3 files changed, 35 insertions, 2 deletions
diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index 5bbd5e709c..29ab7daca0 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -3077,6 +3077,8 @@ void QGuiApplicationPrivate::saveState()
     On system start-up, the default layout direction depends on the
     application's language.
 
+    The notifier signal was introduced in Qt 5.4.
+
     \sa QWidget::layoutDirection, isLeftToRight(), isRightToLeft()
  */
 
@@ -3087,7 +3089,10 @@ void QGuiApplication::setLayoutDirection(Qt::LayoutDirection direction)
 
     layout_direction = direction;
 
-    QGuiApplicationPrivate::self->notifyLayoutDirectionChange();
+    if (qGuiApp) {
+        emit qGuiApp->layoutDirectionChanged(direction);
+        QGuiApplicationPrivate::self->notifyLayoutDirectionChange();
+    }
 }
 
 Qt::LayoutDirection QGuiApplication::layoutDirection()
diff --git a/src/gui/kernel/qguiapplication.h b/src/gui/kernel/qguiapplication.h
index 50aefaadb5..560b2c827d 100644
--- a/src/gui/kernel/qguiapplication.h
+++ b/src/gui/kernel/qguiapplication.h
@@ -75,7 +75,7 @@ class Q_GUI_EXPORT QGuiApplication : public QCoreApplication
     Q_OBJECT
     Q_PROPERTY(QIcon windowIcon READ windowIcon WRITE setWindowIcon)
     Q_PROPERTY(QString applicationDisplayName READ applicationDisplayName WRITE setApplicationDisplayName)
-    Q_PROPERTY(Qt::LayoutDirection layoutDirection READ layoutDirection WRITE setLayoutDirection)
+    Q_PROPERTY(Qt::LayoutDirection layoutDirection READ layoutDirection WRITE setLayoutDirection NOTIFY layoutDirectionChanged)
     Q_PROPERTY(QString platformName READ platformName STORED false)
     Q_PROPERTY(bool quitOnLastWindowClosed  READ quitOnLastWindowClosed WRITE setQuitOnLastWindowClosed)
 
@@ -169,6 +169,7 @@ Q_SIGNALS:
     void focusObjectChanged(QObject *focusObject);
     void focusWindowChanged(QWindow *focusWindow);
     void applicationStateChanged(Qt::ApplicationState state);
+    void layoutDirectionChanged(Qt::LayoutDirection direction);
 #ifndef QT_NO_SESSIONMANAGER
     void commitDataRequest(QSessionManager &sessionManager);
     void saveStateRequest(QSessionManager &sessionManager);
diff --git a/tests/auto/gui/kernel/qguiapplication/tst_qguiapplication.cpp b/tests/auto/gui/kernel/qguiapplication/tst_qguiapplication.cpp
index e1cdb8db45..54b6fc6c44 100644
--- a/tests/auto/gui/kernel/qguiapplication/tst_qguiapplication.cpp
+++ b/tests/auto/gui/kernel/qguiapplication/tst_qguiapplication.cpp
@@ -75,6 +75,7 @@ private slots:
     void modalWindow();
     void quitOnLastWindowClosed();
     void genericPluginsAndWindowSystemEvents();
+    void layoutDirection();
 };
 
 void tst_QGuiApplication::displayName()
@@ -848,4 +849,30 @@ void tst_QGuiApplication::genericPluginsAndWindowSystemEvents()
     QCOMPARE(testReceiver.customEvents, 1);
 }
 
+Q_DECLARE_METATYPE(Qt::LayoutDirection)
+void tst_QGuiApplication::layoutDirection()
+{
+    qRegisterMetaType<Qt::LayoutDirection>();
+
+    Qt::LayoutDirection oldDirection = QGuiApplication::layoutDirection();
+    Qt::LayoutDirection newDirection = oldDirection == Qt::LeftToRight ? Qt::RightToLeft : Qt::LeftToRight;
+
+    QGuiApplication::setLayoutDirection(newDirection);
+    QCOMPARE(QGuiApplication::layoutDirection(), newDirection);
+
+    int argc = 1;
+    char *argv[] = { const_cast<char*>("tst_qguiapplication") };
+    QGuiApplication app(argc, argv);
+    QSignalSpy signalSpy(&app, SIGNAL(layoutDirectionChanged(Qt::LayoutDirection)));
+
+    QGuiApplication::setLayoutDirection(oldDirection);
+    QCOMPARE(QGuiApplication::layoutDirection(), oldDirection);
+    QCOMPARE(signalSpy.count(), 1);
+    QCOMPARE(signalSpy.at(0).at(0).toInt(), static_cast<int>(oldDirection));
+
+    QGuiApplication::setLayoutDirection(oldDirection);
+    QCOMPARE(QGuiApplication::layoutDirection(), oldDirection);
+    QCOMPARE(signalSpy.count(), 1);
+}
+
 QTEST_APPLESS_MAIN(tst_QGuiApplication)