Store button list in the resources section of fake item instead of C++ space

interface/resources/qml/hifi/tablet/Tablet.qml

@@ -30,21 +30,26 @@ Item {
         }
     }
 
-    //fake invisible item for initial buttons creations
+    //fake invisible item for initial buttons creations.
+    //Also used as a holder for buttons list
     Item {
         id: fakeParent
         visible: false
     }
 
     function doRecreateGrids() {
-        var tabletProxy = Tablet.getTablet("com.highfidelity.interface.tablet.system");
-        var tabletButtons = tabletProxy.getButtonsList();
 
-        if (tabletButtons.length <= 0) {
+        if (fakeParent.resources.length <= 0) {
-            console.warn("Tablet buttons list is empty");
+            console.warn("Tablet buttons list is empty", fakeParent.resources.length);
             return;
         }
 
+        //copy buttons list to JS array to be able to sort it
+        var tabletButtons = [];
+        for (var btnIndex = 0; btnIndex < fakeParent.resources.length; btnIndex++) {
+            tabletButtons.push(fakeParent.resources[btnIndex]);
+        }
+
         for (var i = swipeView.count - 1; i >= 0; i--) {
             swipeView.removeItem(i);
         }
@@ -53,7 +58,6 @@ Item {
         swipeView.setCurrentIndex(-1);
         sortButtons(tabletButtons);
 
-        var pagesNum = Math.ceil(tabletButtons.length / 12);
         var currentPage = 0;
         gridPages.push(pageComponent.createObject(null));
 
@@ -87,10 +91,8 @@ Item {
         if (!uuid) {
             return -1;
         }
-        var tabletProxy = Tablet.getTablet("com.highfidelity.interface.tablet.system");
+        for (var i in fakeParent.resources) {
-        var tabletButtons = tabletProxy.getButtonsList();
+            var child = fakeParent.resources[i];
-        for (var i in tabletButtons) {
-            var child = tabletButtons[i];
             if (child.uuid === uuid) {
                 return i;
             }
@@ -129,6 +131,7 @@ Item {
         }
         button.flickable = swipeView.contentItem;
         tablet.count++
+        fakeParent.resources.push(button);
         gridsRecreateTimer.restart();
 
         return button;
@@ -163,6 +166,7 @@ Item {
             console.log("Warning: Tablet.qml could not find button with uuid = " + properties.uuid);
         } else {
             tablet.count--;
+            fakeParent.resources[index] = null;
             //redraw grids
             gridsRecreateTimer.restart();
         }

libraries/ui/src/ui/TabletScriptingInterface.cpp

@@ -716,11 +716,7 @@ TabletButtonProxy* TabletProxy::addButton(const QVariant& properties) {
     }
 
     auto tabletButtonProxy = QSharedPointer<TabletButtonProxy>(new TabletButtonProxy(properties.toMap()));
-    {
+    _tabletButtonProxies.push_back(tabletButtonProxy);
-        QMutexLocker locker(&_tabletButtonsListMutex);
-        _tabletButtonProxies.push_back(tabletButtonProxy);
-
-    }
     if (!_toolbarMode && _qmlTabletRoot) {
         auto tablet = getQmlTablet();
         if (tablet) {
@@ -768,10 +764,7 @@ void TabletProxy::removeButton(TabletButtonProxy* tabletButtonProxy) {
             return;
         }
         buttonProxy = *iter;
-        {
+        _tabletButtonProxies.erase(iter);
-            QMutexLocker locker(&_tabletButtonsListMutex);
-            _tabletButtonProxies.erase(iter);
-        }
     }
     
     if (!_toolbarMode && _qmlTabletRoot) {
@@ -821,11 +814,8 @@ void TabletProxy::addButtonsToHomeScreen() {
         return;
     }
 
-    {
+    for (auto& buttonProxy : _tabletButtonProxies) {
-        QMutexLocker locker(&_tabletButtonsListMutex);
+        addButtonProxyToQmlTablet(tablet, buttonProxy.data());
-        for (auto& buttonProxy : _tabletButtonProxies) {
-            addButtonProxyToQmlTablet(tablet, buttonProxy.data());
-        }
     }
     auto loader = _qmlTabletRoot->findChild<QQuickItem*>("loader");
     QObject::disconnect(loader, SIGNAL(loaded()), this, SLOT(addButtonsToHomeScreen()));
@@ -852,12 +842,9 @@ void TabletProxy::desktopWindowClosed() {
 void TabletProxy::addButtonsToToolbar() {
     Q_ASSERT(QThread::currentThread() == thread());
     ToolbarProxy* toolbarProxy = DependencyManager::get<TabletScriptingInterface>()->getSystemToolbarProxy();
-    {
+    for (auto& buttonProxy : _tabletButtonProxies) {
-        QMutexLocker locker(&_tabletButtonsListMutex);
+        // copy properties from tablet button proxy to toolbar button proxy.
-        for (auto& buttonProxy : _tabletButtonProxies) {
+        buttonProxy->setToolbarButtonProxy(toolbarProxy->addButton(buttonProxy->getProperties()));
-            // copy properties from tablet button proxy to toolbar button proxy.
-            buttonProxy->setToolbarButtonProxy(toolbarProxy->addButton(buttonProxy->getProperties()));
-        }
     }
 
     // make the toolbar visible
@@ -914,19 +901,6 @@ QQuickItem* TabletProxy::getQmlMenu() const {
     return menuList;
 }
 
-QList<QObject *> TabletProxy::getButtonsList() const {
-    QList<QObject *> buttonsList;
-    QMutexLocker locker(&_tabletButtonsListMutex);
-
-    for (auto& buttonProxy : _tabletButtonProxies) {
-        if (buttonProxy->getQmlButton()) {
-            buttonsList.append(buttonProxy->getQmlButton());
-        }
-    }
-
-    return buttonsList;
-}
-
 //
 // TabletButtonProxy
 //
@@ -1007,7 +981,3 @@ void TabletButtonProxy::editProperties(const QVariantMap& properties) {
         QMetaObject::invokeMethod(_toolbarButtonProxy, "editProperties", Qt::AutoConnection, Q_ARG(QVariantMap, properties));
     }
 }
-
-QPointer<QQuickItem> TabletButtonProxy::getQmlButton() const {
-    return _qmlButton;
-}

libraries/ui/src/ui/TabletScriptingInterface.h

@@ -204,13 +204,6 @@ public:
 
     QQuickItem* getQmlMenu() const;
 
-    /**jsdoc
-     * Returns a list of currently created button items.
-     * @function TabletProxy#getButtonsList
-     * @returns {QList<QQuickItem*>}
-     */
-    Q_INVOKABLE QList<QObject*> getButtonsList() const;
-
 signals:
     /**jsdoc
      * Signaled when this tablet receives an event from the html/js embedded in the tablet
@@ -270,7 +263,6 @@ protected:
     std::pair<QVariant, bool> _initialWebPathParams;
     bool _landscape { false };
     bool _showRunningScripts { false };
-    mutable QMutex _tabletButtonsListMutex;
 };
 
 Q_DECLARE_METATYPE(TabletProxy*);
@@ -305,8 +297,6 @@ public:
      */
     Q_INVOKABLE void editProperties(const QVariantMap& properties);
 
-    QPointer<QQuickItem> getQmlButton() const;
-
 public slots:
     void clickedSlot() { emit clicked(); }
 
@@ -321,7 +311,7 @@ signals:
 protected:
     QUuid _uuid;
     int _stableOrder;
-    QPointer<QQuickItem> _qmlButton;
+    QQuickItem* _qmlButton { nullptr };
     QObject* _toolbarButtonProxy { nullptr };
     QVariantMap _properties;
 };