simplify code for switch button-single layout

app/layouts/synchronizer.cpp

@@ -72,6 +72,11 @@ Synchronizer::~Synchronizer()
     m_activitiesController->deleteLater();
 }
 
+KActivities::Controller *Synchronizer::activitiesController() const
+{
+    return m_activitiesController;
+}
+
 bool Synchronizer::latteViewExists(Latte::View *view) const
 {
     for (const auto layout : m_centralLayouts) {

app/layouts/synchronizer.h

@@ -111,6 +111,8 @@ public:
     SharedLayout *sharedLayout(QString id) const;
     Layout::GenericLayout *layout(QString id) const;
 
+    KActivities::Controller *activitiesController() const;
+
 signals:
     void centralLayoutsChanged();
     void currentLayoutNameChanged();

app/settings/settingsdialog.cpp

@@ -654,12 +654,30 @@ void SettingsDialog::on_switchButton_clicked()
 
     if (!m_layoutsController->selectedLayoutIsCurrentActive()) {
         bool appliedShared = m_layoutsController->inMultipleMode() && selectedLayout.isShared();
+        bool freeActivitiesLayoutUpdated{false};
 
         if (!appliedShared && selectedLayout.activities.isEmpty()) {
             m_layoutsController->setLayoutNameForFreeActivities(selectedLayout.currentName(), true);
+            freeActivitiesLayoutUpdated = true;
         }
 
-        m_corona->layoutsManager()->switchToLayout(selectedLayout.originalName());
+        if (m_layoutsController->inMultipleMode()) {
+            m_corona->layoutsManager()->switchToLayout(selectedLayout.originalName());
+        } else {
+            if (freeActivitiesLayoutUpdated) {
+                m_corona->layoutsManager()->switchToLayout(selectedLayout.originalName());
+            } else {
+                CentralLayout singleLayout(this, selectedLayout.id);
+
+                QString switchToActivity = selectedLayout.isForFreeActivities() ? singleLayout.lastUsedActivity() : selectedLayout.activities[0];
+
+                if (!m_corona->activitiesConsumer()->runningActivities().contains(switchToActivity)) {
+                    m_corona->layoutsManager()->synchronizer()->activitiesController()->startActivity(switchToActivity);
+                }
+
+                m_corona->layoutsManager()->synchronizer()->activitiesController()->setCurrentActivity(switchToActivity);
+            }
+        }
     }
 
     updatePerLayoutButtonsState();