Windows QPA: Allow the native Windows virtual keyboard to be disabled

This change provides a way to disable the automatic showing of the native
Windows on-screen virtual keyboard when a text editing widget is
selected on a system without a physical keyboard, by enabling the new
AA_MSWindowsDisableVirtualKeyboard application attribute, allowing
applications to use a custom virtual keyboard implementation.

Fixes: QTBUG-76088
Change-Id: Id76f9673a2e4081e5325662f3e3b4b102d133b9a
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

4 files changed, 13 insertions, 3 deletions

diff --git a/src/corelib/global/qnamespace.h b/src/corelib/global/qnamespace.h
index 047ed8e7b3..5b63daec69 100644
--- a/src/corelib/global/qnamespace.h
+++ b/src/corelib/global/qnamespace.h
@@ -523,6 +523,7 @@ public:
         AA_DontUseNativeMenuBar = 6,
         AA_MacDontSwapCtrlAndMeta = 7,
         AA_Use96Dpi = 8,
+        AA_MSWindowsDisableVirtualKeyboard = 9,
 #if QT_DEPRECATED_SINCE(5, 14)
         AA_X11InitThreads Q_DECL_ENUMERATOR_DEPRECATED = 10,
 #endif
diff --git a/src/corelib/global/qnamespace.qdoc b/src/corelib/global/qnamespace.qdoc
index ef5f345e9c..6149281904 100644
--- a/src/corelib/global/qnamespace.qdoc
+++ b/src/corelib/global/qnamespace.qdoc
@@ -293,6 +293,12 @@
            This attribute must be set before QGuiApplication is constructed.
            This value was added in 5.13
 
+    \value AA_MSWindowsDisableVirtualKeyboard When this attribute is set,
+           Windows' native on-screen virtual keyboard will not be shown
+           automatically when a text input widget gains focus on a system
+           without a physical keyboard.
+           This value was added in 5.15
+
     The following values are deprecated or obsolete:
 
     \value AA_ImmediateWidgetCreation This attribute is no longer fully
diff --git a/src/plugins/platforms/windows/qwindowsinputcontext.cpp b/src/plugins/platforms/windows/qwindowsinputcontext.cpp
index 19d632dc10..f1f5d3a96e 100644
--- a/src/plugins/platforms/windows/qwindowsinputcontext.cpp
+++ b/src/plugins/platforms/windows/qwindowsinputcontext.cpp
@@ -285,7 +285,8 @@ void QWindowsInputContext::showInputPanel()
         // the Surface seems unnecessary there anyway. But leave it hidden for IME.
         // Only trigger the native OSK if the Qt OSK is not in use.
         static bool imModuleEmpty = qEnvironmentVariableIsEmpty("QT_IM_MODULE");
-        if (imModuleEmpty
+        bool nativeVKDisabled = QCoreApplication::testAttribute(Qt::AA_MSWindowsDisableVirtualKeyboard);
+        if ((imModuleEmpty && !nativeVKDisabled)
                 && QOperatingSystemVersion::current()
                     >= QOperatingSystemVersion(QOperatingSystemVersion::Windows, 10, 0, 16299)) {
             ShowCaret(platformWindow->handle());
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.cpp b/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.cpp
index a0a976545f..5f564f81c2 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.cpp
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiamainprovider.cpp
@@ -393,12 +393,14 @@ HRESULT QWindowsUiaMainProvider::GetPropertyValue(PROPERTYID idProp, VARIANT *pR
             // Control type converted from role.
             auto controlType = roleToControlTypeId(accessible->role());
 
-            // The native OSK should be disbled if the Qt OSK is in use.
+            // The native OSK should be disbled if the Qt OSK is in use,
+            // or if disabled via application attribute.
             static bool imModuleEmpty = qEnvironmentVariableIsEmpty("QT_IM_MODULE");
+            bool nativeVKDisabled = QCoreApplication::testAttribute(Qt::AA_MSWindowsDisableVirtualKeyboard);
 
             // If we want to disable the native OSK auto-showing
             // we have to report text fields as non-editable.
-            if (controlType == UIA_EditControlTypeId && !imModuleEmpty)
+            if (controlType == UIA_EditControlTypeId && (!imModuleEmpty || nativeVKDisabled))
                 controlType = UIA_TextControlTypeId;
 
             setVariantI4(controlType, pRetVal);