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
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>
(cherry picked from commit b2103e33f490c96d0068d211c6f2d5b540ca407e)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/tests/auto/quick/qquicktextinput/tst_qquicktextinput.cpp b/tests/auto/quick/qquicktextinput/tst_qquicktextinput.cpp
index 8d15b52462..9e78170ab6 100644
--- a/tests/auto/quick/qquicktextinput/tst_qquicktextinput.cpp
+++ b/tests/auto/quick/qquicktextinput/tst_qquicktextinput.cpp
@@ -5893,6 +5893,7 @@ void tst_qquicktextinput::clear()
 
     textInput->clear();
     QVERIFY(textInput->text().isEmpty());
+    QVERIFY2(textInput->preeditText().isEmpty(), "Pre-edit text must be empty after clear");
 
     QCOMPARE(spy.count(), 3);
 
@@ -5901,6 +5902,7 @@ void tst_qquicktextinput::clear()
     QVERIFY(!textInput->canUndo());
     QCOMPARE(spy.count(), 4);
     QCOMPARE(textInput->text(), QString("I am Legend"));
+    QVERIFY2(textInput->preeditText().isEmpty(), "Pre-edit text must be empty after undo");
 }
 
 void tst_qquicktextinput::backspaceSurrogatePairs()