qquicktextinput: Clear pre-edit text after input method reset

The QPlatformInputContext::reset() function does not allow any further
input method events to be called. Therefore, clearing the pre-edit text
is the sole responsibility of the text input control.

This change modifies the QQuickTextInputPrivate::resetInputMethod()
function and calls QQuickTextInputPrivate::cancelPreedit() instead of
QInputMethod::reset() directly. The cancelPreedit() function will send
a QInputMethodEvent which clears the IM state (in addition of calling
QInputMethod::reset() function).

Also, rename the QQuickTextInputPrivate::resetInputMethod() function to
cancelInput, since it does not call inputMethod()->reset() directly.

Fixes: QTBUG-95461
Pick-to: 5.15 6.1 6.2
Change-Id: I6ab3b9dbe71956af72656e2a25a05d79603b34ea
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Inho Lee <inho.lee@qt.io>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>
Reviewed-by: Jarkko Koivikko <jarkko.koivikko@code-q.fi>

1 files changed, 7 insertions, 5 deletions

diff --git a/src/quick/items/qquicktextinput.cpp b/src/quick/items/qquicktextinput.cpp
index e5922df623..6a663d0d2f 100644
--- a/src/quick/items/qquicktextinput.cpp
+++ b/src/quick/items/qquicktextinput.cpp
@@ -2104,7 +2104,7 @@ void QQuickTextInput::undo()
 {
     Q_D(QQuickTextInput);
     if (!d->m_readOnly) {
-        d->resetInputMethod();
+        d->cancelInput();
         d->internalUndo();
         d->finishChange(-1, true);
     }
@@ -2120,7 +2120,7 @@ void QQuickTextInput::redo()
 {
     Q_D(QQuickTextInput);
     if (!d->m_readOnly) {
-        d->resetInputMethod();
+        d->cancelInput();
         d->internalRedo();
         d->finishChange();
     }
@@ -2747,11 +2747,13 @@ void QQuickTextInputPrivate::init()
     m_inputControl = new QInputControl(QInputControl::LineEdit, q);
 }
 
-void QQuickTextInputPrivate::resetInputMethod()
+void QQuickTextInputPrivate::cancelInput()
 {
+#if QT_CONFIG(im)
     Q_Q(QQuickTextInput);
     if (!m_readOnly && q->hasActiveFocus() && qGuiApp)
-        QGuiApplication::inputMethod()->reset();
+        cancelPreedit();
+#endif // im
 }
 
 void QQuickTextInput::updateCursorRectangle(bool scroll)
@@ -4696,7 +4698,7 @@ void QQuickTextInput::ensureVisible(int position)
 void QQuickTextInput::clear()
 {
     Q_D(QQuickTextInput);
-    d->resetInputMethod();
+    d->cancelInput();
     d->clear();
 }