Make categorized product/example view reusable

Extract a SectionedGridView from the SectionedProducts that are used in
the MarketPlace plugin, and make item delegate and pixmap fetching
function to be used with the model(s) pluggable.

Change-Id: I02aba87b27afd8ad18ff23346d1ac98da906db4b
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/coreplugin/welcomepagehelper.cpp

@@ -13,12 +13,14 @@
 
 #include <QEasingCurve>
 #include <QFontDatabase>
-#include <QHeaderView>
 #include <QHBoxLayout>
+#include <QHeaderView>
 #include <QHoverEvent>
+#include <QLabel>
 #include <QMouseEvent>
 #include <QPainter>
 #include <QPixmapCache>
+#include <QScrollArea>
 #include <QTimer>
 
 #include <qdrawutil.h>
@@ -117,6 +119,22 @@ void GridView::leaveEvent(QEvent *)
     viewportEvent(&hev); // Seemingly needed to kill the hover paint.
 }
 
+SectionGridView::SectionGridView(QWidget *parent)
+    : GridView(parent)
+{}
+
+bool SectionGridView::hasHeightForWidth() const
+{
+    return true;
+}
+
+int SectionGridView::heightForWidth(int width) const
+{
+    const int columnCount = width / Core::ListItemDelegate::GridItemWidth;
+    const int rowCount = (model()->rowCount() + columnCount - 1) / columnCount;
+    return rowCount * Core::ListItemDelegate::GridItemHeight;
+}
+
 const QSize ListModel::defaultImageSize(214, 160);
 
 ListModel::ListModel(QObject *parent)
@@ -126,10 +144,23 @@ ListModel::ListModel(QObject *parent)
 
 ListModel::~ListModel()
 {
-    qDeleteAll(m_items);
+    if (m_ownsItems)
+        qDeleteAll(m_items);
     m_items.clear();
 }
 
+void ListModel::appendItems(const QList<ListItem *> &items)
+{
+    beginInsertRows(QModelIndex(), m_items.size(), m_items.size() + items.size());
+    m_items.append(items);
+    endInsertRows();
+}
+
+const QList<ListItem *> ListModel::items() const
+{
+    return m_items;
+}
+
 int ListModel::rowCount(const QModelIndex &) const
 {
     return m_items.size();
@@ -166,6 +197,11 @@ void ListModel::setPixmapFunction(const PixmapFunction &fetchPixmapAndUpdatePixm
     m_fetchPixmapAndUpdatePixmapCache = fetchPixmapAndUpdatePixmapCache;
 }
 
+void ListModel::setOwnsItems(bool owns)
+{
+    m_ownsItems = owns;
+}
+
 ListModelFilter::ListModelFilter(ListModel *sourceModel, QObject *parent) :
     QSortFilterProxyModel(parent)
 {
@@ -346,6 +382,11 @@ void ListModelFilter::setSearchString(const QString &arg)
     delayedUpdateFilter();
 }
 
+ListModel *ListModelFilter::sourceListModel() const
+{
+    return static_cast<ListModel *>(sourceModel());
+}
+
 bool ListModelFilter::leaveFilterAcceptsRowBeforeFiltering(const ListItem *, bool *) const
 {
     return false;
@@ -583,4 +624,93 @@ void ListItemDelegate::goon()
         m_currentWidget->update(m_previousIndex);
 }
 
+SectionedGridView::SectionedGridView(QWidget *parent)
+    : QStackedWidget(parent)
+    , m_allItemsView(new Core::GridView(this))
+{
+    auto allItemsModel = new ListModel(this);
+    allItemsModel->setPixmapFunction(m_pixmapFunction);
+    // it just "borrows" the items from the section models:
+    allItemsModel->setOwnsItems(false);
+    m_filteredAllItemsModel = new Core::ListModelFilter(allItemsModel, this);
+
+    auto area = new QScrollArea(this);
+    area->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    area->setVerticalScrollBarPolicy(Qt::ScrollBarAsNeeded);
+    area->setFrameShape(QFrame::NoFrame);
+    area->setWidgetResizable(true);
+
+    auto sectionedView = new QWidget;
+    auto layout = new QVBoxLayout;
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->addStretch();
+    sectionedView->setLayout(layout);
+    area->setWidget(sectionedView);
+
+    addWidget(area);
+
+    m_allItemsView->setModel(m_filteredAllItemsModel);
+    addWidget(m_allItemsView);
+}
+
+SectionedGridView::~SectionedGridView() = default;
+
+void SectionedGridView::setItemDelegate(QAbstractItemDelegate *delegate)
+{
+    m_allItemsView->setItemDelegate(delegate);
+    for (GridView *view : std::as_const(m_gridViews))
+        view->setItemDelegate(delegate);
+}
+
+void SectionedGridView::setPixmapFunction(const Core::ListModel::PixmapFunction &pixmapFunction)
+{
+    m_pixmapFunction = pixmapFunction;
+    auto allProducts = static_cast<ListModel *>(m_filteredAllItemsModel->sourceModel());
+    allProducts->setPixmapFunction(pixmapFunction);
+    for (ListModel *model : std::as_const(m_sectionModels))
+        model->setPixmapFunction(pixmapFunction);
+}
+
+void SectionedGridView::setSearchString(const QString &searchString)
+{
+    int view = searchString.isEmpty() ? 0  // sectioned view
+                                      : 1; // search view
+    setCurrentIndex(view);
+    m_filteredAllItemsModel->setSearchString(searchString);
+}
+
+ListModel *SectionedGridView::addSection(const Section &section, const QList<ListItem *> &items)
+{
+    auto model = new ListModel(this);
+    model->setPixmapFunction(m_pixmapFunction);
+    model->appendItems(items);
+
+    auto gridView = new SectionGridView(this);
+    gridView->setItemDelegate(m_allItemsView->itemDelegate());
+    gridView->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    gridView->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    gridView->setModel(model);
+
+    m_sectionModels.insert(section, model);
+    const auto it = m_gridViews.insert(section, gridView);
+
+    auto sectionLabel = new QLabel(section.name);
+    sectionLabel->setContentsMargins(0, Core::WelcomePageHelpers::ItemGap, 0, 0);
+    sectionLabel->setFont(Core::WelcomePageHelpers::brandFont());
+    auto scrollArea = qobject_cast<QScrollArea *>(widget(0));
+    auto vbox = qobject_cast<QVBoxLayout *>(scrollArea->widget()->layout());
+
+    // insert new section depending on its priority, but before the last (stretch) item
+    int position = std::distance(m_gridViews.begin(), it) * 2; // a section has a label and a grid
+    QTC_ASSERT(position <= vbox->count() - 1, position = vbox->count() - 1);
+    vbox->insertWidget(position, sectionLabel);
+    vbox->insertWidget(position + 1, gridView);
+
+    // add the items also to the all products model to be able to search correctly
+    auto allProducts = static_cast<ListModel *>(m_filteredAllItemsModel->sourceModel());
+    allProducts->appendItems(items);
+
+    return model;
+}
+
 } // namespace Core