Add QMainWindow::GroupedDragging DockOption

If this setting is enabled, the entire group of docked tabs will
be draggable by the title bar of the group and and individual dock
can be dragged by dragging the tab.

When tabs are detached, the docks that are contained are reparented to
a QDockWidgetGroupWindow.

[ChangeLog][QtWidgets][QMainWindow] Added GroupedDragging as a DockOption
which allow users to drag all the tabs together when dragging the
title of a QDockWidget which is tabbed with others.

Change-Id: I5285685b129770498eb3e4fd5f4556e41225a595
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Reviewed-by: Paul Olav Tvete <paul.tvete@theqtcompany.com>

3 files changed, 12 insertions, 7 deletions

diff --git a/examples/widgets/mainwindows/mainwindow/colorswatch.cpp b/examples/widgets/mainwindows/mainwindow/colorswatch.cpp
index 408f6c4b0f..7499389dc3 100644
--- a/examples/widgets/mainwindows/mainwindow/colorswatch.cpp
+++ b/examples/widgets/mainwindows/mainwindow/colorswatch.cpp
@@ -248,8 +248,8 @@ void ColorDock::setCustomSizeHint(const QSize &size)
     updateGeometry();
 }
 
-ColorSwatch::ColorSwatch(const QString &colorName, QWidget *parent, Qt::WindowFlags flags)
-    : QDockWidget(parent, flags)
+ColorSwatch::ColorSwatch(const QString &colorName, QMainWindow *parent, Qt::WindowFlags flags)
+    : QDockWidget(parent, flags), mainWindow(parent)
 {
     setObjectName(colorName + QLatin1String(" Dock Widget"));
     setWindowTitle(objectName() + QLatin1String(" [*]"));
@@ -390,7 +390,6 @@ ColorSwatch::ColorSwatch(const QString &colorName, QWidget *parent, Qt::WindowFl
 
 void ColorSwatch::updateContextMenu()
 {
-    QMainWindow *mainWindow = qobject_cast<QMainWindow *>(parentWidget());
     const Qt::DockWidgetArea area = mainWindow->dockWidgetArea(this);
     const Qt::DockWidgetAreas areas = allowedAreas();
 
@@ -458,7 +457,6 @@ void ColorSwatch::updateContextMenu()
 
 void ColorSwatch::splitInto(QAction *action)
 {
-    QMainWindow *mainWindow = qobject_cast<QMainWindow *>(parentWidget());
     QList<ColorSwatch*> dock_list = mainWindow->findChildren<ColorSwatch*>();
     ColorSwatch *target = 0;
     foreach (ColorSwatch *dock, dock_list) {
@@ -477,7 +475,6 @@ void ColorSwatch::splitInto(QAction *action)
 
 void ColorSwatch::tabInto(QAction *action)
 {
-    QMainWindow *mainWindow = qobject_cast<QMainWindow *>(parentWidget());
     QList<ColorSwatch*> dock_list = mainWindow->findChildren<ColorSwatch*>();
     ColorSwatch *target = 0;
     foreach (ColorSwatch *dock, dock_list) {
@@ -525,7 +522,6 @@ void ColorSwatch::place(Qt::DockWidgetArea area, bool p)
 {
     if (!p) return;
 
-    QMainWindow *mainWindow = qobject_cast<QMainWindow *>(parentWidget());
     mainWindow->addDockWidget(area, this);
 
     if (allowedAreasActions->isEnabled()) {
diff --git a/examples/widgets/mainwindows/mainwindow/colorswatch.h b/examples/widgets/mainwindows/mainwindow/colorswatch.h
index 6d02592b22..78f267c320 100644
--- a/examples/widgets/mainwindows/mainwindow/colorswatch.h
+++ b/examples/widgets/mainwindows/mainwindow/colorswatch.h
@@ -70,8 +70,10 @@ class ColorSwatch : public QDockWidget
 
     QAction *windowModifiedAction;
 
+    QMainWindow *mainWindow;
+
 public:
-    explicit ColorSwatch(const QString &colorName, QWidget *parent = 0, Qt::WindowFlags flags = 0);
+    explicit ColorSwatch(const QString &colorName, QMainWindow *parent = 0, Qt::WindowFlags flags = 0);
 
     QMenu *menu;
     void setCustomSizeHint(const QSize &size);
diff --git a/examples/widgets/mainwindows/mainwindow/mainwindow.cpp b/examples/widgets/mainwindows/mainwindow/mainwindow.cpp
index 70a8644b47..ea557c7aa9 100644
--- a/examples/widgets/mainwindows/mainwindow/mainwindow.cpp
+++ b/examples/widgets/mainwindows/mainwindow/mainwindow.cpp
@@ -156,6 +156,11 @@ void MainWindow::setupMenuBar()
     action->setChecked(dockOptions() & VerticalTabs);
     connect(action, SIGNAL(toggled(bool)), this, SLOT(setDockOptions()));
 
+    action = mainWindowMenu->addAction(tr("Grouped dragging"));
+    action->setCheckable(true);
+    action->setChecked(dockOptions() & GroupedDragging);
+    connect(action, SIGNAL(toggled(bool)), this, SLOT(setDockOptions()));
+
     QMenu *toolBarMenu = menuBar()->addMenu(tr("Tool bars"));
     for (int i = 0; i < toolBars.count(); ++i)
         toolBarMenu->addMenu(toolBars.at(i)->menu);
@@ -187,6 +192,8 @@ void MainWindow::setDockOptions()
         opts |= ForceTabbedDocks;
     if (actions.at(4)->isChecked())
         opts |= VerticalTabs;
+    if (actions.at(5)->isChecked())
+        opts |= GroupedDragging;
 
     QMainWindow::setDockOptions(opts);
 }