fix property changed signals firing multiple times

Plugins/ZShell/Components/carouselview.cpp

@@ -1,11 +1,13 @@
 #include "carouselview.hpp"
 
+#include <QSignalBlocker>
 #include <QQmlContext>
 #include <QQmlProperty>
 #include <QMouseEvent>
 #include <QWheelEvent>
 
 #include <cmath>
+#include <qobject.h>
 
 namespace ZShell::components {
 
@@ -81,6 +83,33 @@ void CarouselView::setDelegate(QQmlComponent* c) {
 	relayout();
 }
 
+void CarouselView::notifyCurrentIndexChanged() {
+	if (!m_completed) return;
+	emit currentIndexChanged();
+}
+
+void CarouselView::notifyCurrentItemChanged() {
+	if (!m_completed) return;
+	emit currentItemChanged();
+}
+
+void CarouselView::notifyPreviewIndexChanged(int realIndex) {
+	if (!m_completed || realIndex < 0) return;
+	emit previewIndexChanged(realIndex, m_model.at(realIndex));
+}
+
+void CarouselView::classBegin() {}
+
+void CarouselView::componentComplete() {
+	m_completed = true;
+	emit currentIndexChanged();
+	if (m_currentRealIndex >= 0 && m_currentRealIndex < m_model.size())
+		emit previewIndexChanged(
+			m_currentRealIndex, m_model.at(m_currentRealIndex));
+
+	emit currentItemChanged();
+}
+
 bool CarouselView::childMouseEventFilter(QQuickItem* item, QEvent* event) {
 	Q_UNUSED(item);
 
@@ -163,7 +192,7 @@ void CarouselView::setModel(const QVariantList& m) {
 	if (newCount == 0) {
 		m_currentRealIndex = -1;
 		m_currentItem = nullptr;
-		emit currentItemChanged();
+		notifyCurrentItemChanged();
 
 		releaseAllItems();
 		rebuildArrangement();
@@ -173,19 +202,23 @@ void CarouselView::setModel(const QVariantList& m) {
 
 	if (!m_initializedLayout) {
 		m_centerBlockStart = 0;
-		m_currentVirtualIndex = 0;
 
-		m_contentX = contentXForIndex(0);
+		const int startVirtual =
+			m_pendingCurrentIndex >= 0
+				? qBound(0, m_pendingCurrentIndex, newCount - 1)
+				: 0;
 
+		m_pendingCurrentIndex = -1;
+
+		m_currentVirtualIndex = startVirtual;
+		m_contentX = contentXForIndex(startVirtual);
 		m_currentRealIndex = realIndexOf(m_currentVirtualIndex);
-
 		m_previewRealIndex = m_currentRealIndex;
 
 		m_initializedLayout = true;
 
 		m_layoutCapacity =
 			qMax(m_layoutCapacity, layoutCapacityForWidth(m_maxWidth));
-
 		setImplicitWidth(targetWidthForMaxWidth(m_maxWidth));
 
 		rebuildArrangement();
@@ -320,6 +353,22 @@ void CarouselView::setDelegateProperties(const QVariantMap& v) {
 }
 
 void CarouselView::setCurrentIndex(int idx) {
+	if (m_model.isEmpty()) {
+		m_pendingCurrentIndex = idx;
+
+		if (m_currentRealIndex != idx) {
+			m_currentRealIndex = idx;
+			notifyCurrentIndexChanged();
+		}
+
+		return;
+	}
+
+	if (!m_completed) {
+		centerInstantlyOnReal(idx);
+		return;
+	}
+
 	goToIndex(idx);
 }
 
@@ -336,7 +385,7 @@ void CarouselView::updateCurrentItem() {
 	if (item == m_currentItem) return;
 
 	m_currentItem = item;
-	emit currentItemChanged();
+	notifyCurrentItemChanged();
 }
 
 void CarouselView::geometryChange(const QRectF& newGeo, const QRectF& oldGeo) {
@@ -676,15 +725,12 @@ void CarouselView::updateCurrentIndexFromContentX(bool emitPreview) {
 	if (newReal != m_currentRealIndex) {
 		m_currentRealIndex = newReal;
 
-		emit currentIndexChanged();
+		notifyCurrentIndexChanged();
 	}
 
 	if (emitPreview && newReal != m_previewRealIndex) {
 		m_previewRealIndex = newReal;
-
-		if (newReal >= 0) {
-			emit previewIndexChanged(newReal, m_model.at(newReal));
-		}
+		notifyPreviewIndexChanged(newReal);
 	}
 }
 
@@ -1029,13 +1075,14 @@ void CarouselView::glideTo(qreal dest) {
 
 	cancelAnimations();
 
-	m_glideAnim->setDuration(m_glideDuration);
+	{
+		QSignalBlocker blocker(m_glideAnim);
 
-	m_glideAnim->setStartValue(m_contentX);
-
-	m_glideAnim->setEndValue(dest);
-
-	m_glideAnim->start();
+		m_glideAnim->setDuration(m_glideDuration);
+		m_glideAnim->setStartValue(m_contentX);
+		m_glideAnim->setEndValue(dest);
+		m_glideAnim->start();
+	}
 }
 
 void CarouselView::snapToNearest() {
@@ -1078,10 +1125,6 @@ void CarouselView::decrementCurrentIndex() {
 	glideTo(contentXForIndex(m_currentVirtualIndex - 1));
 }
 
-void CarouselView::jumpToIndex(int realIndex) {
-	centerInstantlyOnReal(realIndex);
-}
-
 void CarouselView::centerInstantlyOnReal(int realIndex) {
 	const int count = m_model.size();
 
@@ -1115,7 +1158,7 @@ void CarouselView::centerInstantlyOnReal(int realIndex) {
 
 	if (changed) emit currentIndexChanged();
 
-	emit previewIndexChanged(realIndex, m_model.at(realIndex));
+	notifyPreviewIndexChanged(realIndex);
 
 	relayout();
 }
@@ -1219,12 +1262,16 @@ void CarouselView::mouseReleaseEvent(QMouseEvent* event) {
 
 	cancelAnimations();
 
-	m_flickAnim->setDuration(
-		static_cast<int>(qBound<qreal>(120, duration, 900)));
-	m_flickAnim->setEasingCurve(QEasingCurve::OutQuad);
-	m_flickAnim->setStartValue(m_contentX);
-	m_flickAnim->setEndValue(dest);
-	m_flickAnim->start();
+	{
+		QSignalBlocker blocker(m_flickAnim);
+
+		m_flickAnim->setDuration(
+			static_cast<int>(qBound<qreal>(120, duration, 900)));
+		m_flickAnim->setEasingCurve(QEasingCurve::OutQuad);
+		m_flickAnim->setStartValue(m_contentX);
+		m_flickAnim->setEndValue(dest);
+		m_flickAnim->start();
+	}
 
 	event->accept();
 }