Add applicationDisplayNameChanged() signal.

If applicationDisplayName has not been set, the signal is emitted when
applicationNameChanged() is emitted.

[ChangeLog][QtGui][General] Add
QGuiApplication::applicationDisplayNameChanged() signal.

Task-number: QTBUG-53076
Change-Id: I18494ad90bd8dec3f79ef5175a3a85e776560fd0
Reviewed-by: David Faure <david.faure@kdab.com>

2 files changed, 21 insertions, 6 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index a125b39d67..d0bfc7ff5f 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -656,9 +656,20 @@ QGuiApplicationPrivate::QGuiApplicationPrivate(int &argc, char **argv, int flags
 */
 void QGuiApplication::setApplicationDisplayName(const QString &name)
 {
-    if (!QGuiApplicationPrivate::displayName)
-        QGuiApplicationPrivate::displayName = new QString;
-    *QGuiApplicationPrivate::displayName = name;
+    if (!QGuiApplicationPrivate::displayName) {
+        QGuiApplicationPrivate::displayName = new QString(name);
+        if (qGuiApp) {
+            disconnect(qGuiApp, &QGuiApplication::applicationNameChanged,
+                    qGuiApp, &QGuiApplication::applicationDisplayNameChanged);
+
+            if (QGuiApplicationPrivate::displayName != applicationName())
+                emit qGuiApp->applicationDisplayNameChanged();
+        }
+    } else if (name != *QGuiApplicationPrivate::displayName) {
+        *QGuiApplicationPrivate::displayName = name;
+        if (qGuiApp)
+            emit qGuiApp->applicationDisplayNameChanged();
+    }
 }
 
 QString QGuiApplication::applicationDisplayName()
@@ -1424,9 +1435,8 @@ void QGuiApplicationPrivate::init()
     init_plugins(pluginList);
     QWindowSystemInterface::flushWindowSystemEvents();
 
-#ifndef QT_NO_SESSIONMANAGER
     Q_Q(QGuiApplication);
-
+#ifndef QT_NO_SESSIONMANAGER
     // connect to the session manager
     session_manager = new QSessionManager(q, session_id, session_key);
 #endif
@@ -1455,6 +1465,10 @@ void QGuiApplicationPrivate::init()
 
     if (layout_direction == Qt::LayoutDirectionAuto || force_reverse)
         QGuiApplication::setLayoutDirection(qt_detectRTLLanguage() ? Qt::RightToLeft : Qt::LeftToRight);
+
+    if (!QGuiApplicationPrivate::displayName)
+        QObject::connect(q, &QGuiApplication::applicationNameChanged,
+                         q, &QGuiApplication::applicationDisplayNameChanged);
 }
 
 extern void qt_cleanupFontDatabase();
diff --git a/src/gui/kernel/qguiapplication.h b/src/gui/kernel/qguiapplication.h
index 10057c5b7f..725d7cb59d 100644
--- a/src/gui/kernel/qguiapplication.h
+++ b/src/gui/kernel/qguiapplication.h
@@ -72,7 +72,7 @@ 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(QString applicationDisplayName READ applicationDisplayName WRITE setApplicationDisplayName NOTIFY applicationDisplayNameChanged)
     Q_PROPERTY(QString desktopFileName READ desktopFileName WRITE setDesktopFileName)
     Q_PROPERTY(Qt::LayoutDirection layoutDirection READ layoutDirection WRITE setLayoutDirection NOTIFY layoutDirectionChanged)
     Q_PROPERTY(QString platformName READ platformName STORED false)
@@ -183,6 +183,7 @@ Q_SIGNALS:
     void saveStateRequest(QSessionManager &sessionManager);
 #endif
     void paletteChanged(const QPalette &pal);
+    void applicationDisplayNameChanged();
 
 protected:
     bool event(QEvent *) Q_DECL_OVERRIDE;