Overhaul main view accessibility

This commit brings the main view of Dolphin into a usable state
accessibility-wise. Users of screen readers should have a way better
experience while browsing files and folders and navigating along the
file system hierarchy.

This commit fixes most of the remaining already-identified
accessibility issues listed in
https://invent.kde.org/teams/accessibility/collaboration/-/issues/28,
but not all. Namely, these should now be fixed:

1. Orca should read the element type in dolphin (file, folder, device,
link to folder, link to file)
2. Orca should read complete label in icon and compact view mode,
currently it only speaks the name, but there could be additional
information like the number of elements or the file size.
3. Orca is not able to announce Selecting / Unselecting files in
Dolphin. It also never announces how many items are selected in total.
(Announcing the total selection can be done by reading out the view
element or by pressing the Tab key to get to the status bar with the
relevant information.)
4. Dolphin opens on the home directory, but Orca doesn't tell you so.
Consider enclosing the area in a frame/panel which updates its
accessible name each time you modify the current path by entering or
leaving a directory.
5. I don't know what the folder presentation widget is, but it should
be presented as a grid view. Currently, we have a terrible experience
because the entire row of folders is read at once, with no indication
that we can move left and right with the arrows to go between the
elements of a row. When I found that out, however, I discovered that
when you're on the last icon of the first row and press right arrow,
you get to the first icon of the next row, but that's not announced,
instead, the whole row is announced at once
6. Orca should announce the current elements instead of "layered pane"
when the Folder / File view gets the focus in dolphin
7. Orca reads only name in Table View only of Dolphin
8. Items are sometimes confusingly announced as "collapsed" in contexts
in which there is no concept of collapsing/expanding e.g. in icon view
mode.

A lot of code was moved around and renamed. The three accessibility
classes, which all used to be in the same file, are moved into separate
files.

*Acknowledgement*
Thanks to Christian Hempfling and bgt lover for testing as well as
originally identifying a lot of the pain points being addressed here.

This work is part of a my project funded through the NGI0 Entrust Fund,
a fund established by NLnet with financial support from the European
Commission's Next Generation Internet programme, under the aegis of DG
Communications Networks, Content and Technology.
https://kde.org/announcements/2024_ngi_openletter/

1 files changed, 51 insertions, 10 deletions

diff --git a/src/kitemviews/kitemlistview.cpp b/src/kitemviews/kitemlistview.cpp
index afc392810..b0ea32940 100644
--- a/src/kitemviews/kitemlistview.cpp
+++ b/src/kitemviews/kitemlistview.cpp
@@ -8,12 +8,16 @@
 
 #include "kitemlistview.h"
 
+#ifndef QT_NO_ACCESSIBILITY
+#include "accessibility/kitemlistcontaineraccessible.h"
+#include "accessibility/kitemlistdelegateaccessible.h"
+#include "accessibility/kitemlistviewaccessible.h"
+#endif
 #include "dolphindebug.h"
 #include "kitemlistcontainer.h"
 #include "kitemlistcontroller.h"
 #include "kitemlistheader.h"
 #include "kitemlistselectionmanager.h"
-#include "kitemlistviewaccessible.h"
 #include "kstandarditemlistwidget.h"
 
 #include "private/kitemlistheaderwidget.h"
@@ -1240,6 +1244,11 @@ void KItemListView::slotItemsInserted(const KItemRangeList &itemRanges)
     if (useAlternateBackgrounds()) {
         updateAlternateBackgrounds();
     }
+#ifndef QT_NO_ACCESSIBILITY
+    if (QAccessible::isActive()) { // Announce that the count of items has changed.
+        static_cast<KItemListViewAccessible *>(QAccessible::queryAccessibleInterface(this))->announceDescriptionChange();
+    }
+#endif
 }
 
 void KItemListView::slotItemsRemoved(const KItemRangeList &itemRanges)
@@ -1358,6 +1367,11 @@ void KItemListView::slotItemsRemoved(const KItemRangeList &itemRanges)
     if (useAlternateBackgrounds()) {
         updateAlternateBackgrounds();
     }
+#ifndef QT_NO_ACCESSIBILITY
+    if (QAccessible::isActive()) { // Announce that the count of items has changed.
+        static_cast<KItemListViewAccessible *>(QAccessible::queryAccessibleInterface(this))->announceDescriptionChange();
+    }
+#endif
 }
 
 void KItemListView::slotItemsMoved(const KItemRange &itemRange, const QList<int> &movedToIndexes)
@@ -1416,10 +1430,12 @@ void KItemListView::slotItemsChanged(const KItemRangeList &itemRanges, const QSe
             doLayout(NoAnimation);
         }
 
+#ifndef QT_NO_ACCESSIBILITY
         QAccessibleTableModelChangeEvent ev(this, QAccessibleTableModelChangeEvent::DataChanged);
         ev.setFirstRow(itemRange.index);
         ev.setLastRow(itemRange.index + itemRange.count);
         QAccessible::updateAccessibility(&ev);
+#endif
     }
 
     doLayout(NoAnimation);
@@ -1483,8 +1499,6 @@ void KItemListView::slotSortRoleChanged(const QByteArray &current, const QByteAr
 
 void KItemListView::slotCurrentChanged(int current, int previous)
 {
-    Q_UNUSED(previous)
-
     // In SingleSelection mode (e.g., in the Places Panel), the current item is
     // always the selected item. It is not necessary to highlight the current item then.
     if (m_controller->selectionBehavior() != KItemListController::SingleSelection) {
@@ -1496,25 +1510,52 @@ void KItemListView::slotCurrentChanged(int current, int previous)
         KItemListWidget *currentWidget = m_visibleItems.value(current, nullptr);
         if (currentWidget) {
             currentWidget->setCurrent(true);
+            if (hasFocus() || (previousWidget && previousWidget->hasFocus())) {
+                currentWidget->setFocus(); // Mostly for accessibility, because keyboard events are handled correctly either way.
+            }
         }
     }
-
-    QAccessibleEvent ev(this, QAccessible::Focus);
-    ev.setChild(current);
-    QAccessible::updateAccessibility(&ev);
+#ifndef QT_NO_ACCESSIBILITY
+    if (QAccessible::isActive()) {
+        if (current >= 0) {
+            QAccessibleEvent accessibleFocusCurrentItemEvent(this, QAccessible::Focus);
+            accessibleFocusCurrentItemEvent.setChild(current);
+            QAccessible::updateAccessibility(&accessibleFocusCurrentItemEvent);
+        }
+        static_cast<KItemListViewAccessible *>(QAccessible::queryAccessibleInterface(this))->announceDescriptionChange();
+    }
+#endif
 }
 
 void KItemListView::slotSelectionChanged(const KItemSet &current, const KItemSet &previous)
 {
-    Q_UNUSED(previous)
-
     QHashIterator<int, KItemListWidget *> it(m_visibleItems);
     while (it.hasNext()) {
         it.next();
         const int index = it.key();
         KItemListWidget *widget = it.value();
-        widget->setSelected(current.contains(index));
+        const bool isSelected(current.contains(index));
+        widget->setSelected(isSelected);
+
+#ifndef QT_NO_ACCESSIBILITY
+        if (!QAccessible::isActive()) {
+            continue;
+        }
+        // Let the screen reader announce "selected" or "not selected" for the active item.
+        const bool wasSelected(previous.contains(index));
+        if (isSelected != wasSelected) {
+            QAccessibleEvent accessibleSelectionChangedEvent(this, QAccessible::Selection);
+            accessibleSelectionChangedEvent.setChild(index);
+            QAccessible::updateAccessibility(&accessibleSelectionChangedEvent);
+        }
     }
+    // Usually the below does not have an effect because the view will not have focus at this moment but one of its list items. Still we announce the
+    // change of the accessibility description just in case the user manually moved focus up by one.
+    static_cast<KItemListViewAccessible *>(QAccessible::queryAccessibleInterface(this))->announceDescriptionChange();
+#else
+    }
+    Q_UNUSED(previous)
+#endif
 }
 
 void KItemListView::slotAnimationFinished(QGraphicsWidget *widget, KItemListViewAnimation::AnimationType type)