Have special keyboard controls in selection mode

Prior to this commit keyboard controls and behaviour of Dolphin's main
view were identical no matter if selection mode was enabled or not.
While selection mode makes it impossible to accidentally clear the
selection by singular mouse clicks, any press of an arrow key on the
keyboard would still clear the full selection which goes against
selection mode's objective.

Furthermore, keyboard-only users had no reason to ever enable selection
mode because it made no difference to them.

This commit changes this by offering a changed control scheme for key
presses while in selection mode. Arrow key presses without modifier now
only move focus between items but do no longer clear or change the
selection. Similarly, Page Up/Down, Home, and End key presses only move
keyboard focus. Enter, Return, and Space key presses now only toggle
the selection for the current item.

The above controls are however mostly unchanged when combining them
with Modifier keys like Shift or Control.

The type-ahead feature is also changed in selection mode to only move
keyboard focus without changing the selection.

This way keyboard users are less likely to clear their selection by
mistake. Regression tests are added for these selection mode controls.

The code changes to change this keyboard behaviour are quite minimal.
Most of the added code is for making selection mode accessible. That's
because we need to make sure the changed control scheme is properly
announced and communicated or a blind user will be left utterly
confused why the normal keyboard controls "stopped working".

Enabling or disabling selection mode is announced to accessibility
software. Furthermore whenever focus goes to the main view, the
selection mode state is also mentioned when active.

BUG: 458091

3 files changed, 51 insertions, 5 deletions

diff --git a/src/kitemviews/accessibility/kitemlistviewaccessible.cpp b/src/kitemviews/accessibility/kitemlistviewaccessible.cpp
index f8c14bf4a..f58527be6 100644
--- a/src/kitemviews/accessibility/kitemlistviewaccessible.cpp
+++ b/src/kitemviews/accessibility/kitemlistviewaccessible.cpp
@@ -280,8 +280,18 @@ QString KItemListViewAccessible::text(QAccessible::Text t) const
             if (numberOfSelectedItems < 1 || (numberOfSelectedItems == 1 && isSelected(currentItem))) {
                 // We do not announce the number of selected items if the only selected item is the current item
                 // because the selection state of the current item is already announced elsewhere.
+                if (m_selectionMode) {
+                    return i18nc("@info accessibility, 1 is path", "in a grid layout in selection mode in location %1", modelRootUrl.toDisplayString());
+                }
                 return i18nc("@info accessibility, 1 is path", "in a grid layout in location %1", modelRootUrl.toDisplayString());
             }
+            if (m_selectionMode) {
+                return i18ncp("@info accessibility, 2 is path",
+                              "%1 selected item in a grid layout in selection mode in location %2",
+                              "%1 selected items in a grid layout in selection mode in location %2",
+                              numberOfSelectedItems,
+                              modelRootUrl.toDisplayString());
+            }
             return i18ncp("@info accessibility, 2 is path",
                           "%1 selected item in a grid layout in location %2",
                           "%1 selected items in a grid layout in location %2",
@@ -293,8 +303,18 @@ QString KItemListViewAccessible::text(QAccessible::Text t) const
     if (numberOfSelectedItems < 1 || (numberOfSelectedItems == 1 && isSelected(currentItem))) {
         // We do not announce the number of selected items if the only selected item is the current item
         // because the selection state of the current item is already announced elsewhere.
+        if (m_selectionMode) {
+            return i18nc("@info accessibility, 1 is path", "in selection mode in location %1", modelRootUrl.toDisplayString());
+        }
         return i18nc("@info accessibility, 1 is path", "in location %1", modelRootUrl.toDisplayString());
     }
+    if (m_selectionMode) {
+        return i18ncp("@info accessibility, 2 is path",
+                      "%1 selected item in selection mode in location %2",
+                      "%1 selected items in selection mode in location %2",
+                      numberOfSelectedItems,
+                      modelRootUrl.toDisplayString());
+    }
     return i18ncp("@info accessibility, 2 is path",
                   "%1 selected item in location %2",
                   "%1 selected items in location %2",
@@ -490,3 +510,14 @@ void KItemListViewAccessible::slotAnnounceCurrentItemTimerTimeout()
         QAccessible::updateAccessibility(&announceAccessibleDescriptionEvent);
     }
 }
+
+void KItemListViewAccessible::announceSelectionModeEnabled(const bool enabled)
+{
+    m_selectionMode = enabled;
+#if QT_VERSION >= QT_VERSION_CHECK(6, 8, 0) // QAccessibleAnnouncementEvent is only available since 6.8
+    QAccessibleAnnouncementEvent announceChangedControlsEvent(view(),
+                                                              enabled ? i18nc("accessibility announcement", "Selection mode enabled")
+                                                                      : i18nc("accessibility announcement", "Selection mode disabled"));
+    QAccessible::updateAccessibility(&announceChangedControlsEvent);
+#endif
+}
diff --git a/src/kitemviews/accessibility/kitemlistviewaccessible.h b/src/kitemviews/accessibility/kitemlistviewaccessible.h
index db2832435..64b5a2442 100644
--- a/src/kitemviews/accessibility/kitemlistviewaccessible.h
+++ b/src/kitemviews/accessibility/kitemlistviewaccessible.h
@@ -124,6 +124,12 @@ public:
      */
     void announceCurrentItem();
 
+    /**
+     * Toggling selection mode completely changes how the application controls, so it is absolutely necessary to communicate this change to users as soon as it
+     * happens.
+     */
+    void announceSelectionModeEnabled(bool enabled);
+
 private:
     /**
      * @returns a KItemListDelegateAccessible representing the file or folder at the @index. Returns nullptr for invalid indices.
@@ -144,6 +150,7 @@ private Q_SLOTS:
 private:
     /** @see setPlaceholderMessage(). */
     QString m_placeholderMessage;
+    bool m_selectionMode = false;
 
     /**
      * Is started by announceCurrentItem().
diff --git a/src/kitemviews/kitemlistcontroller.cpp b/src/kitemviews/kitemlistcontroller.cpp
index 821e1b75f..2ae4a1f25 100644
--- a/src/kitemviews/kitemlistcontroller.cpp
+++ b/src/kitemviews/kitemlistcontroller.cpp
@@ -270,7 +270,9 @@ bool KItemListController::keyPressEvent(QKeyEvent *event)
     }
 
     const bool controlPressed = event->modifiers() & Qt::ControlModifier;
-    const bool shiftOrControlPressed = shiftPressed || controlPressed;
+    if (m_selectionMode && !controlPressed && !shiftPressed && (key == Qt::Key_Enter || key == Qt::Key_Return)) {
+        key = Qt::Key_Space; // In selection mode one moves around with arrow keys and toggles selection with Enter.
+    }
     const bool navigationPressed = key == Qt::Key_Home || key == Qt::Key_End || key == Qt::Key_PageUp || key == Qt::Key_PageDown || key == Qt::Key_Up
         || key == Qt::Key_Down || key == Qt::Key_Left || key == Qt::Key_Right;
 
@@ -467,7 +469,7 @@ bool KItemListController::keyPressEvent(QKeyEvent *event)
 
     case Qt::Key_Space:
         if (m_selectionBehavior == MultiSelection) {
-            if (controlPressed) {
+            if (controlPressed || m_selectionMode) {
                 // Toggle the selection state of the current item.
                 m_selectionManager->endAnchoredSelection();
                 m_selectionManager->setSelected(index, 1, KItemListSelectionManager::Toggle);
@@ -503,13 +505,13 @@ bool KItemListController::keyPressEvent(QKeyEvent *event)
             break;
 
         case MultiSelection:
-            if (controlPressed) {
+            if (controlPressed || (m_selectionMode && !shiftPressed)) {
                 m_selectionManager->endAnchoredSelection();
             }
 
             m_selectionManager->setCurrentItem(index);
 
-            if (!shiftOrControlPressed) {
+            if (!shiftPressed && !controlPressed && !m_selectionMode) {
                 m_selectionManager->clearSelection();
                 m_selectionManager->setSelected(index, 1);
             }
@@ -540,10 +542,16 @@ void KItemListController::slotChangeCurrentItem(const QString &text, bool search
         index = m_model->indexForKeyboardSearch(text, 0);
     }
     if (index >= 0) {
+        if (m_selectionMode) {
+            m_selectionManager->endAnchoredSelection();
+        }
+
         m_selectionManager->setCurrentItem(index);
 
         if (m_selectionBehavior != NoSelection) {
-            m_selectionManager->replaceSelection(index);
+            if (!m_selectionMode) { // Don't clear the selection in selection mode.
+                m_selectionManager->replaceSelection(index);
+            }
             m_selectionManager->beginAnchoredSelection(index);
         }