Extending the inputMethodQuery API

Currently, inputMethodQuery() only provides information about the
current paragraph. On some platforms, such as Android, the input method
needs information about the global cursor position, and more of the
surrounding text. Some queries need to pass parameters.

The current inputmethodQuery() implementation does not allow parameters to
be passed. Changing this would require new or modified virtual functions, which
is not possible until Qt 6. Therefore, a completely new mechanism is needed.

Change-Id: Ic64fd90198ade70aa0fa6fa5ad3867dfa7ed763c
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

2 files changed, 28 insertions, 0 deletions

diff --git a/src/gui/kernel/qinputmethod.cpp b/src/gui/kernel/qinputmethod.cpp
index 438c169f71..495ea8f6e7 100644
--- a/src/gui/kernel/qinputmethod.cpp
+++ b/src/gui/kernel/qinputmethod.cpp
@@ -45,6 +45,8 @@
 #include <qtimer.h>
 #include <qpa/qplatforminputcontext_p.h>
 
+#include <QDebug>
+
 QT_BEGIN_NAMESPACE
 
 /*!
@@ -365,6 +367,29 @@ bool QInputMethodPrivate::objectAcceptsInputMethod(QObject *object)
     return enabled;
 }
 
+/*!
+  Send \a query to the current focus object with parameters \a argument and return the result.
+ */
+QVariant QInputMethod::queryFocusObject(Qt::InputMethodQuery query, QVariant argument)
+{
+    QVariant retval;
+    QObject *focusObject = qGuiApp->focusObject();
+    if (!focusObject)
+        return retval;
+
+    bool newMethodWorks = QMetaObject::invokeMethod(focusObject, "inputMethodQuery",
+                                                    Qt::DirectConnection,
+                                                    Q_RETURN_ARG(QVariant, retval),
+                                                    Q_ARG(Qt::InputMethodQuery, query),
+                                                    Q_ARG(QVariant, argument));
+    if (newMethodWorks)
+        return retval;
+
+    QInputMethodQueryEvent queryEvent(query);
+    QCoreApplication::sendEvent(focusObject, &queryEvent);
+    return queryEvent.value(query);
+}
+
 QT_END_NAMESPACE
 
 #include "moc_qinputmethod.cpp"
diff --git a/src/gui/kernel/qinputmethod.h b/src/gui/kernel/qinputmethod.h
index fe6cc3f331..b155b5c0ca 100644
--- a/src/gui/kernel/qinputmethod.h
+++ b/src/gui/kernel/qinputmethod.h
@@ -50,6 +50,7 @@ class QInputMethodPrivate;
 class QWindow;
 class QRectF;
 class QTransform;
+class QInputMethodQueryEvent;
 
 class Q_GUI_EXPORT QInputMethod : public QObject
 {
@@ -89,6 +90,8 @@ public:
     QLocale locale() const;
     Qt::LayoutDirection inputDirection() const;
 
+    static QVariant queryFocusObject(Qt::InputMethodQuery query, QVariant argument);
+
 public Q_SLOTS:
     void show();
     void hide();