QmlDesigner: Allow dropping materials on User Assets

Fixes: QDS-14444
Change-Id: Ic3dd93709497cbb9c14eba2ff784ef00d9b975d7
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>

share/qtcreator/qmldesigner/contentLibraryQmlSource/ContentLibraryUserView.qml

@@ -116,8 +116,8 @@ Item {
                     onCountChanged: root.assignMaxCount()
 
                     onDropEnter: (drag) => {
-                        drag.accepted = categoryTitle === "Textures"
+                        drag.accepted = (categoryTitle === "Textures" && drag.formats[0] === "application/vnd.qtdesignstudio.assets")
-                                     && drag.formats[0] === "application/vnd.qtdesignstudio.assets"
+                                     || (categoryTitle === "Materials" && drag.formats[0] === "application/vnd.qtdesignstudio.material")
 
                         section.highlight = drag.accepted
                     }
@@ -128,9 +128,13 @@ Item {
 
                     onDrop: (drag) => {
                         section.highlight = false
-                        ContentLibraryBackend.rootView.acceptTexturesDrop(drag.urls)
                         drag.accept()
                         section.expandSection()
+
+                        if (categoryTitle === "Textures")
+                            ContentLibraryBackend.rootView.acceptTexturesDrop(drag.urls)
+                        else if (categoryTitle === "Materials")
+                            ContentLibraryBackend.rootView.acceptMaterialDrop(drag.getDataAsString(drag.formats[0]))
                     }
 
                     Grid {

share/qtcreator/qmldesigner/materialBrowserQmlSource/MaterialBrowserContextMenu.qml

@@ -130,7 +130,6 @@ StudioControls.Menu {
 
     StudioControls.MenuItem {
         text: qsTr("Add to Content Library")
-        enabled: !materialBrowserModel.selectedMaterialIsComponent
 
         onTriggered: MaterialBrowserBackend.rootView.addMaterialToContentLibrary()
     }

src/plugins/qmldesigner/components/contentlibrary/contentlibraryview.cpp

@@ -100,6 +100,13 @@ WidgetInfo ContentLibraryView::widgetInfo()
             addLibAssets(paths);
         });
 
+        connect(m_widget, &ContentLibraryWidget::acceptMaterialDrop, this,
+                [this](const QString &internalId) {
+            ModelNode matNode = QmlDesignerPlugin::instance()->viewManager()
+                                .view()->modelNodeForInternalId(internalId.toInt());
+            addLibItem(matNode);
+        });
+
         connect(m_widget,
                 &ContentLibraryWidget::addTextureRequested,
                 this,

src/plugins/qmldesigner/components/contentlibrary/contentlibrarywidget.h

@@ -125,6 +125,7 @@ signals:
     void importBundle();
     void requestTab(int tabIndex);
     void acceptTexturesDrop(const QList<QUrl> &urls);
+    void acceptMaterialDrop(const QString &internalId);
 
 protected:
     bool eventFilter(QObject *obj, QEvent *event) override;