Add explicit, use nullptr etc.

applets/notifications/plugin/draghelper.h

@@ -33,7 +33,7 @@ Q_OBJECT
 Q_PROPERTY(bool dragActive READ dragActive NOTIFY dragActiveChanged)
 
 public:
-    DragHelper(QObject *parent = nullptr);
+    explicit DragHelper(QObject *parent = nullptr);
     ~DragHelper();
 
     bool dragActive() const;

applets/notifications/plugin/notificationshelper.h

@@ -48,7 +48,7 @@ public:
     };
     Q_ENUM(PositionOnScreen)
 
-    NotificationsHelper(QObject *parent = nullptr);
+    explicit NotificationsHelper(QObject *parent = nullptr);
     ~NotificationsHelper() override;
     Q_INVOKABLE void addNotificationPopup(QObject *win);
     Q_INVOKABLE void closePopup(const QString &sourceName);

applets/notifications/plugin/thumbnailer.cpp

@@ -133,7 +133,7 @@ void Thumbnailer::showContextMenu(int x, int y, const QString &path, QQuickItem
     });
 
     if (KProtocolManager::supportsListing(url)) {
-        QAction *openContainingFolderAction = menu->addAction(QIcon::fromTheme("folder-open"), i18n("Open Containing Folder"));
+        QAction *openContainingFolderAction = menu->addAction(QIcon::fromTheme(QStringLiteral("folder-open")), i18n("Open Containing Folder"));
         connect(openContainingFolderAction, &QAction::triggered, [url] {
             KIO::highlightInFileManager({url});
         });
@@ -158,7 +158,7 @@ void Thumbnailer::showContextMenu(int x, int y, const QString &path, QQuickItem
     actions->addServiceActionsTo(menu);
     actions->addPluginActionsTo(menu);
 
-    QAction *propertiesAction = menu->addAction(QIcon::fromTheme("document-properties"), i18n("Properties"));
+    QAction *propertiesAction = menu->addAction(QIcon::fromTheme(QStringLiteral("document-properties")), i18n("Properties"));
     connect(propertiesAction, &QAction::triggered, [fileItem] {
         KPropertiesDialog *dialog = new KPropertiesDialog(fileItem.url());
         dialog->setAttribute(Qt::WA_DeleteOnClose);

applets/systemtray/container/systemtraycontainer.cpp

@@ -79,7 +79,7 @@ void SystemTrayContainer::ensureSystrayExists()
     }
 
     if (!m_innerContainment) {
-        m_innerContainment = c->createContainment("org.kde.plasma.private.systemtray", QVariantList() << "org.kde.plasma:force-create");
+        m_innerContainment = c->createContainment(QStringLiteral("org.kde.plasma.private.systemtray"), QVariantList() << "org.kde.plasma:force-create");
         config().writeEntry("SystrayContainmentId", m_innerContainment->id());
     }
 

applets/systemtray/systemtray.cpp

@@ -346,7 +346,7 @@ bool SystemTray::isSystemTrayApplet(const QString &appletId)
 void SystemTray::restoreContents(KConfigGroup &group)
 {
     Q_UNUSED(group);
-    //NOTE: RestoreContents shouldnn't do anything here because is too soon, so have an empty reimplementation
+    //NOTE: RestoreContents shouldn't do anything here because is too soon, so have an empty reimplementation
 }
 
 void SystemTray::restorePlasmoids()