Revert "[Android] Remove signal and slot mechanism to listen states in editor's"

This reverts commit a40a512dec0f34e84eb63812af556608f03713ff.
It caused UI freezes and cursor position inconsistencies.
See the linked bugs.

Pick-to: 6.2 6.2.1 5.15
Task-number: QTBUG-58013
Task-number: QTBUG-93414
Task-number: QTBUG-95669
Task-number: QTBUG-96671
Task-number: QTBUG-96675
Task-number: QTBUG-96769
Change-Id: Ie8100538609a1460713ca9115cdbe329654d0772
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>

2 files changed, 8 insertions, 37 deletions

diff --git a/src/plugins/platforms/android/qandroidinputcontext.cpp b/src/plugins/platforms/android/qandroidinputcontext.cpp
index fb51e1dba1..bfc1a1109f 100644
--- a/src/plugins/platforms/android/qandroidinputcontext.cpp
+++ b/src/plugins/platforms/android/qandroidinputcontext.cpp
@@ -882,44 +882,9 @@ void QAndroidInputContext::update(Qt::InputMethodQueries queries)
     QSharedPointer<QInputMethodQueryEvent> query = focusObjectInputMethodQuery(queries);
     if (query.isNull())
         return;
-
-    if (query->value(Qt::ImCursorPosition).toInt() >= 0 &&
-            query->value(Qt::ImSurroundingText).toString()
-            .left(query->value(Qt::ImCursorPosition).toInt()).length() >= 0) {
-
-        // Cursor position should be always valid
-        // when object is composing
-        if (focusObjectIsComposing())
-            return;
-
-        // NOTE: This seems to be happening sometimes
-        // when qt quick application is booted up
-        if (m_focusObject == nullptr)
-            return;
-
-        if (m_focusObject->isWidgetType())
-            updateCursorPosition();
-        else
-            updateCursorPositionInRange(query);
-    }
-}
-
-void QAndroidInputContext::updateCursorPositionInRange(const QSharedPointer<QInputMethodQueryEvent> &query)
-{
-    QObject *input = qGuiApp->focusObject();
-    QList<QInputMethodEvent::Attribute> attributes;
-    attributes.append(QInputMethodEvent::Attribute(QInputMethodEvent::Cursor,
-                                                   query->value(Qt::ImCursorPosition).toInt(), 1));
-
-    QInputMethodEvent event(QString(), attributes);
-    QCoreApplication::sendEvent(input, &event);
-
-    QtAndroidInput::updateSelection(query->value(Qt::ImCursorPosition).toInt(),
-                                    query->value(Qt::ImCursorPosition).toInt(), 0,
-                                    query->value(Qt::ImSurroundingText).toString().length());
+#warning TODO extract the needed data from query
 }
 
-
 void QAndroidInputContext::invokeAction(QInputMethod::Action action, int cursorPosition)
 {
 #warning TODO Handle at least QInputMethod::ContextMenu action
@@ -950,6 +915,12 @@ void QAndroidInputContext::showInputPanel()
     if (query.isNull())
         return;
 
+    disconnect(m_updateCursorPosConnection);
+    if (qGuiApp->focusObject()->metaObject()->indexOfSignal("cursorPositionChanged(int,int)") >= 0) // QLineEdit breaks the pattern
+        m_updateCursorPosConnection = connect(qGuiApp->focusObject(), SIGNAL(cursorPositionChanged(int,int)), this, SLOT(updateCursorPosition()));
+    else
+        m_updateCursorPosConnection = connect(qGuiApp->focusObject(), SIGNAL(cursorPositionChanged()), this, SLOT(updateCursorPosition()));
+
     QRect rect = cursorRect();
     if (!isInputPanelVisible())
         QtAndroidInput::showSoftwareKeyboard(rect.left(), rect.top(), rect.width(), rect.height(),
diff --git a/src/plugins/platforms/android/qandroidinputcontext.h b/src/plugins/platforms/android/qandroidinputcontext.h
index 521061b02c..02a66c367a 100644
--- a/src/plugins/platforms/android/qandroidinputcontext.h
+++ b/src/plugins/platforms/android/qandroidinputcontext.h
@@ -156,13 +156,13 @@ private:
     void focusObjectStartComposing();
     bool focusObjectStopComposing();
     QRect cursorRect();
-    void updateCursorPositionInRange(const QSharedPointer<QInputMethodQueryEvent> &query);
 
 private:
     ExtractedText m_extractedText;
     QString m_composingText;
     int m_composingTextStart;
     int m_composingCursor;
+    QMetaObject::Connection m_updateCursorPosConnection;
     HandleModes m_handleMode;
     int m_batchEditNestingLevel;
     QObject *m_focusObject;