Add Selection Mode

The selection mode action is a checkable toggle action named
"Select Files and Folders" which has "Space" as the default
shortcut.

In selection mode a bottom bar with contextual actions is shown.
These should mostly mirror the actions which are available through
the right-click context menu aka DolphinContextMenu.

Resizing of the window might make a overflow button appear in the
bottom selection mode bar.

This commit makes press and hold in the view activate selection
mode. This behaviour is not triggered if the press and hold is
used to either start a rubberband selection or a drag operation
within a short time. The length of the short timeframe is defined
by a QStyleHint. This is currently not implemented in touch
because I can't test it.

Mix the selection mode bars' background colors using a nice
combination of colors from the current color scheme

BUG: 427202

1 files changed, 37 insertions, 5 deletions

diff --git a/src/kitemviews/kitemlistcontroller.cpp b/src/kitemviews/kitemlistcontroller.cpp
index 3d83bc914..03ee5cfe6 100644
--- a/src/kitemviews/kitemlistcontroller.cpp
+++ b/src/kitemviews/kitemlistcontroller.cpp
@@ -27,12 +27,14 @@
 #include <QGraphicsSceneEvent>
 #include <QGraphicsView>
 #include <QMimeData>
+#include <QStyleHints>
 #include <QTimer>
 #include <QTouchEvent>
 
 KItemListController::KItemListController(KItemModelBase* model, KItemListView* view, QObject* parent) :
     QObject(parent),
     m_singleClickActivationEnforced(false),
+    m_selectionMode(false),
     m_selectionTogglePressed(false),
     m_clearSelectionIfItemsAreNotDragged(false),
     m_isSwipeGesture(false),
@@ -51,6 +53,7 @@ KItemListController::KItemListController(KItemModelBase* model, KItemListView* v
     m_pressedIndex(std::nullopt),
     m_pressedMousePos(),
     m_autoActivationTimer(nullptr),
+    m_longPressDetectionTimer(nullptr),
     m_swipeGesture(Qt::CustomGesture),
     m_twoFingerTapGesture(Qt::CustomGesture),
     m_oldSelection(),
@@ -69,6 +72,15 @@ KItemListController::KItemListController(KItemModelBase* model, KItemListView* v
     m_autoActivationTimer->setInterval(-1);
     connect(m_autoActivationTimer, &QTimer::timeout, this, &KItemListController::slotAutoActivationTimeout);
 
+    m_longPressDetectionTimer = new QTimer(this);
+    m_longPressDetectionTimer->setSingleShot(true);
+    m_longPressDetectionTimer->setInterval(QGuiApplication::styleHints()->mousePressAndHoldInterval());
+    connect(m_longPressDetectionTimer, &QTimer::timeout, this, [this]() {
+        if (!m_selectionMode) {
+            Q_EMIT selectionModeRequested();
+        }
+    });
+
     setModel(model);
     setView(view);
 
@@ -220,6 +232,16 @@ bool KItemListController::singleClickActivationEnforced() const
     return m_singleClickActivationEnforced;
 }
 
+void KItemListController::setSelectionMode(bool enabled)
+{
+    m_selectionMode = enabled;
+}
+
+bool KItemListController::selectionMode() const
+{
+    return m_selectionMode;
+}
+
 bool KItemListController::keyPressEvent(QKeyEvent* event)
 {
     int index = m_selectionManager->currentItem();
@@ -576,10 +598,14 @@ bool KItemListController::mouseMoveEvent(QGraphicsSceneMouseEvent* event, const
         return false;
     }
 
+    const QPointF pos = transform.map(event->pos());
+    if ((pos - m_pressedMousePos).manhattanLength() >= QApplication::startDragDistance()) {
+        m_longPressDetectionTimer->stop();
+    }
+
     if (m_pressedIndex.has_value() && !m_view->rubberBand()->isActive()) {
         // Check whether a dragging should be started
         if (event->buttons() & Qt::LeftButton) {
-            const QPointF pos = transform.map(event->pos());
             if ((pos - m_pressedMousePos).manhattanLength() >= QApplication::startDragDistance()) {
                 if (!m_selectionManager->isSelected(m_pressedIndex.value())) {
                     // Always assure that the dragged item gets selected. Usually this is already
@@ -639,6 +665,8 @@ bool KItemListController::mouseReleaseEvent(QGraphicsSceneMouseEvent* event, con
         m_view->m_tapAndHoldIndicator->setActive(false);
     }
 
+    m_longPressDetectionTimer->stop();
+
     KItemListRubberBand* rubberBand = m_view->rubberBand();
     if (event->source() == Qt::MouseEventSynthesizedByQt && !rubberBand->isActive() && m_isTouchEvent) {
         return false;
@@ -1247,7 +1275,7 @@ void KItemListController::slotRubberBandChanged()
         // been activated in case if no Shift- or Control-key are pressed
         const bool shiftOrControlPressed = QApplication::keyboardModifiers() & Qt::ShiftModifier ||
                                            QApplication::keyboardModifiers() & Qt::ControlModifier;
-        if (!shiftOrControlPressed) {
+        if (!shiftOrControlPressed && !m_selectionMode) {
             m_oldSelection.clear();
         }
     }
@@ -1296,7 +1324,7 @@ void KItemListController::slotRubberBandChanged()
         }
     } while (!selectionFinished);
 
-    if (QApplication::keyboardModifiers() & Qt::ControlModifier) {
+    if ((QApplication::keyboardModifiers() & Qt::ControlModifier) || m_selectionMode) {
         // If Control is pressed, the selection state of all items in the rubberband is toggled.
         // Therefore, the new selection contains:
         // 1. All previously selected items which are not inside the rubberband, and
@@ -1518,10 +1546,14 @@ bool KItemListController::onPress(const QPoint& screenPos, const QPointF& pos, c
     }
 
     const bool shiftPressed = modifiers & Qt::ShiftModifier;
-    const bool controlPressed = modifiers & Qt::ControlModifier;
+    const bool controlPressed = (modifiers & Qt::ControlModifier) || m_selectionMode;
     const bool leftClick = buttons & Qt::LeftButton;
     const bool rightClick = buttons & Qt::RightButton;
 
+    if (leftClick) {
+        m_longPressDetectionTimer->start();
+    }
+
     // The previous selection is cleared if either
     // 1. The selection mode is SingleSelection, or
     // 2. the selection mode is MultiSelection, and *none* of the following conditions are met:
@@ -1565,7 +1597,7 @@ bool KItemListController::onPress(const QPoint& screenPos, const QPointF& pos, c
                 return false;
             }
         }
-    } else if (pressedItemAlreadySelected && !shiftOrControlPressed && (buttons & Qt::LeftButton)) {
+    } else if (pressedItemAlreadySelected && !shiftOrControlPressed && leftClick) {
         // The user might want to start dragging multiple items, but if he clicks the item
         // in order to trigger it instead, the other selected items must be deselected.
         // However, we do not know yet what the user is going to do.