QmlDesigner: Start and end transaction for spin box dragging

Using the spin box focus is not safe enough, but using
transactions on the dragging works nicely.

Change-Id: Iffc15b4ca44cb473b257f58e548ff86ebd56bbf2
Reviewed-by: Henning Gründl <henning.gruendl@qt.io>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

share/qtcreator/qmldesigner/propertyEditorQmlSources/imports/HelperWidgets/SpinBox.qml

@@ -46,11 +46,30 @@ Item {
     width: 96
     implicitHeight: spinBox.height
 
+    onFocusChanged: transaction.end();
+
     StudioControls.RealSpinBox {
         id: spinBox
 
-        onDragStarted: hideCursor();
+        onDragStarted: {
-        onDragEnded: restoreCursor();
+            hideCursor();
+            transaction.start();
+        }
+
+        onDragEnded: {
+            restoreCursor();
+            transaction.end();
+        }
+
+        onRealValueModified: {
+            if (transaction.active())
+                commitValue();
+        }
+
+        function commitValue() {
+            if (spinBox.backendValue.value !== spinBox.realValue)
+                spinBox.backendValue.value = spinBox.realValue;
+        }
 
         property variant backendValue
         property bool hasSlider: wrapper.sliderIndicatorVisible
@@ -77,9 +96,6 @@ Item {
 
         labelColor: spinBox.edit ? StudioTheme.Values.themeTextColor : colorLogic.textColor
 
-        onCompressedRealValueModified: {
+        onCompressedRealValueModified: commitValue()
-            if (spinBox.backendValue.value !== spinBox.realValue)
-                spinBox.backendValue.value = spinBox.realValue;
-        }
     }
 }

src/plugins/qmldesigner/components/propertyeditor/propertyeditortransaction.cpp

@@ -41,7 +41,7 @@ void PropertyEditorTransaction::start()
     if (m_rewriterTransaction.isValid())
         m_rewriterTransaction.commit();
     m_rewriterTransaction = m_propertyEditor->beginRewriterTransaction(QByteArrayLiteral("PropertyEditorTransaction::start"));
-    m_timerId = startTimer(4000);
+    m_timerId = startTimer(10000);
 }
 
 void PropertyEditorTransaction::end()
@@ -52,6 +52,11 @@ void PropertyEditorTransaction::end()
     }
 }
 
+bool PropertyEditorTransaction::active() const
+{
+    return m_rewriterTransaction.isValid();
+}
+
 void PropertyEditorTransaction::timerEvent(QTimerEvent *timerEvent)
 {
     if (timerEvent->timerId() != m_timerId)

src/plugins/qmldesigner/components/propertyeditor/propertyeditortransaction.h

@@ -38,6 +38,8 @@ public:
     Q_INVOKABLE void start();
     Q_INVOKABLE void end();
 
+    Q_INVOKABLE bool active() const;
+
 protected:
      void timerEvent(QTimerEvent *event) override;