ProjectExplorer: Make project window state persistent

Task-number: QTCREATORBUG-24690
Change-Id: Ia261fc5a98681676e8d67e6d840f2f48073cdbb2
Reviewed-by: hjk <hjk@qt.io>

src/plugins/projectexplorer/projectwindow.cpp

@@ -661,8 +661,38 @@ void ProjectWindow::activateProjectPanel(Utils::Id panelId)
     d->activateProjectPanel(panelId);
 }
 
+void ProjectWindow::hideEvent(QHideEvent *event)
+{
+    savePersistentSettings();
+    FancyMainWindow::hideEvent(event);
+}
+
+void ProjectWindow::showEvent(QShowEvent *event)
+{
+    loadPersistentSettings();
+    FancyMainWindow::showEvent(event);
+}
+
 ProjectWindow::~ProjectWindow() = default;
 
+const char PROJECT_WINDOW_KEY[] = "ProjectExplorer.ProjectWindow";
+
+void ProjectWindow::savePersistentSettings() const
+{
+    QSettings * const settings = ICore::settings();
+    settings->beginGroup(PROJECT_WINDOW_KEY);
+    saveSettings(settings);
+    settings->endGroup();
+}
+
+void ProjectWindow::loadPersistentSettings()
+{
+    QSettings * const settings = ICore::settings();
+    settings->beginGroup(PROJECT_WINDOW_KEY);
+    restoreSettings(settings);
+    settings->endGroup();
+}
+
 QSize SelectorDelegate::sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const
 {
     QSize s = QStyledItemDelegate::sizeHint(option, index);

src/plugins/projectexplorer/projectwindow.h

@@ -64,6 +64,12 @@ public:
     void activateProjectPanel(Utils::Id panelId);
 
 private:
+    void hideEvent(QHideEvent *event) override;
+    void showEvent(QShowEvent *event) override;
+
+    void savePersistentSettings() const;
+    void loadPersistentSettings();
+
     const std::unique_ptr<ProjectWindowPrivate> d;
 };