Windows QPA: Fix QComboBox accessibility with screen readers

Screen readers like NVDA and Narrator were not reading the contents
of a QComboBox when changing its value using the keyboard, without
expanding it, due to missing UI Automation notifications in this case.
This change should also help in other cases where updated string
values were not notified to screen readers.

Fixes: QTBUG-75066
Change-Id: Id7f488380aec5ad27fd11b3cf854d44ab1b28688
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

3 files changed, 39 insertions, 2 deletions

diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.cpp b/src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.cpp
index 85a931e015..c7c0deab3f 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.cpp
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiaaccessibility.cpp
@@ -113,6 +113,9 @@ void QWindowsUiaAccessibility::notifyAccessibilityUpdate(QAccessibleEvent *event
     case QAccessible::ValueChanged:
         QWindowsUiaMainProvider::notifyValueChange(static_cast<QAccessibleValueChangeEvent *>(event));
         break;
+    case QAccessible::SelectionAdd:
+        QWindowsUiaMainProvider::notifySelectionChange(event);
+        break;
     case QAccessible::TextAttributeChanged:
     case QAccessible::TextColumnChanged:
     case QAccessible::TextInserted:
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.cpp b/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.cpp
index fad83fb165..44328492a6 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.cpp
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.cpp
@@ -146,9 +146,33 @@ void QWindowsUiaMainProvider::notifyStateChange(QAccessibleStateChangeEvent *eve
 void QWindowsUiaMainProvider::notifyValueChange(QAccessibleValueChangeEvent *event)
 {
     if (QAccessibleInterface *accessible = event->accessibleInterface()) {
-       if (QAccessibleValueInterface *valueInterface = accessible->valueInterface()) {
-           // Notifies changes in values of controls supporting the value interface.
+        if (accessible->role() == QAccessible::ComboBox && accessible->childCount() > 0) {
+            QAccessibleInterface *listacc = accessible->child(0);
+            if (listacc && listacc->role() == QAccessible::List) {
+                int count = listacc->childCount();
+                for (int i = 0; i < count; ++i) {
+                    QAccessibleInterface *item = listacc->child(i);
+                    if (item && item->text(QAccessible::Name) == event->value()) {
+                        if (!item->state().selected) {
+                            if (QAccessibleActionInterface *actionInterface = item->actionInterface())
+                                actionInterface->doAction(QAccessibleActionInterface::toggleAction());
+                        }
+                        break;
+                    }
+                }
+            }
+        }
+        if (event->value().type() == QVariant::String) {
+            if (QWindowsUiaMainProvider *provider = providerForAccessible(accessible)) {
+                // Notifies changes in string values.
+                VARIANT oldVal, newVal;
+                clearVariant(&oldVal);
+                setVariantString(event->value().toString(), &newVal);
+                QWindowsUiaWrapper::instance()->raiseAutomationPropertyChangedEvent(provider, UIA_ValueValuePropertyId, oldVal, newVal);
+            }
+        } else if (QAccessibleValueInterface *valueInterface = accessible->valueInterface()) {
             if (QWindowsUiaMainProvider *provider = providerForAccessible(accessible)) {
+                // Notifies changes in values of controls supporting the value interface.
                 VARIANT oldVal, newVal;
                 clearVariant(&oldVal);
                 setVariantDouble(valueInterface->currentValue().toDouble(), &newVal);
@@ -158,6 +182,15 @@ void QWindowsUiaMainProvider::notifyValueChange(QAccessibleValueChangeEvent *eve
     }
 }
 
+void QWindowsUiaMainProvider::notifySelectionChange(QAccessibleEvent *event)
+{
+    if (QAccessibleInterface *accessible = event->accessibleInterface()) {
+        if (QWindowsUiaMainProvider *provider = providerForAccessible(accessible)) {
+            QWindowsUiaWrapper::instance()->raiseAutomationEvent(provider, UIA_SelectionItem_ElementSelectedEventId);
+        }
+    }
+}
+
 // Notifies changes in text content and selection state of text controls.
 void QWindowsUiaMainProvider::notifyTextChange(QAccessibleEvent *event)
 {
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.h
index 325d5b3de4..df0d60f9c9 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.h
@@ -68,6 +68,7 @@ public:
     static void notifyFocusChange(QAccessibleEvent *event);
     static void notifyStateChange(QAccessibleStateChangeEvent *event);
     static void notifyValueChange(QAccessibleValueChangeEvent *event);
+    static void notifySelectionChange(QAccessibleEvent *event);
     static void notifyTextChange(QAccessibleEvent *event);
 
     // IUnknown