QQmlDelegateModel: even for QAIM, only use first column by default

In 2f9afadd5d9b4899397dca, we introduced a change in QQmlAdaptorModel
so that a QAIM model report that it contains "rows * cols" number of
model items, and not just "rows". This was needed, otherwise TableView
would only display the first column of such models.

It turns out, however, that also ListView will now detect that a
QAIM contain more items than just the items in the first column.
The result will be that it ends up adding all the other columns
underneath the first column in the view.

To avoid this unforseen change, this patch will revert this logic, and
instead add a private variable that can be set if the new behavior
is wanted (e.g by TableView).

Change-Id: I8c13da99f05e2f922362e498d1fa1779cdbd0d72
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

6 files changed, 58 insertions, 5 deletions

diff --git a/src/qml/types/qqmldelegatemodel.cpp b/src/qml/types/qqmldelegatemodel.cpp
index 68bb185eaa..33fe5f3438 100644
--- a/src/qml/types/qqmldelegatemodel.cpp
+++ b/src/qml/types/qqmldelegatemodel.cpp
@@ -213,6 +213,7 @@ QQmlDelegateModelPrivate::QQmlDelegateModelPrivate(QQmlContext *ctxt)
     , m_transaction(false)
     , m_incubatorCleanupScheduled(false)
     , m_waitingToFetchMore(false)
+    , m_useFirstColumnOnly(true)
     , m_cacheItems(nullptr)
     , m_items(nullptr)
     , m_persistedItems(nullptr)
@@ -227,6 +228,11 @@ QQmlDelegateModelPrivate::~QQmlDelegateModelPrivate()
         m_cacheMetaType->release();
 }
 
+int QQmlDelegateModelPrivate::adaptorModelCount() const
+{
+    return m_useFirstColumnOnly ? m_adaptorModel.rowCount() : m_adaptorModel.count();
+}
+
 void QQmlDelegateModelPrivate::requestMoreIfNecessary()
 {
     Q_Q(QQmlDelegateModel);
@@ -336,7 +342,7 @@ void QQmlDelegateModel::componentComplete()
         static_cast<QQmlPartsModel *>(d->m_pendingParts.first())->updateFilterGroup();
 
     QVector<Compositor::Insert> inserts;
-    d->m_count = d->m_adaptorModel.count();
+    d->m_count = d->adaptorModelCount();
     d->m_compositor.append(
             &d->m_adaptorModel,
             0,
@@ -383,7 +389,7 @@ void QQmlDelegateModel::setModel(const QVariant &model)
     }
 
     if (d->m_complete) {
-        _q_itemsInserted(0, d->m_adaptorModel.count());
+        _q_itemsInserted(0, d->adaptorModelCount());
         d->requestMoreIfNecessary();
     }
 }
@@ -475,7 +481,7 @@ void QQmlDelegateModel::setRootIndex(const QVariant &root)
         if (d->m_adaptorModel.canFetchMore())
             d->m_adaptorModel.fetchMore();
         if (d->m_complete) {
-            const int newCount = d->m_adaptorModel.count();
+            const int newCount = d->adaptorModelCount();
             if (oldCount)
                 _q_itemsRemoved(0, oldCount);
             if (newCount)
@@ -1545,7 +1551,7 @@ void QQmlDelegateModel::_q_modelReset()
     d->m_adaptorModel.rootIndex = QModelIndex();
 
     if (d->m_complete) {
-        d->m_count = d->m_adaptorModel.count();
+        d->m_count = d->adaptorModelCount();
 
         const QList<QQmlDelegateModelItem *> cache = d->m_cache;
         for (int i = 0, c = cache.count();  i < c; ++i) {
diff --git a/src/qml/types/qqmldelegatemodel_p_p.h b/src/qml/types/qqmldelegatemodel_p_p.h
index d5f79fab62..a0c1f6aa12 100644
--- a/src/qml/types/qqmldelegatemodel_p_p.h
+++ b/src/qml/types/qqmldelegatemodel_p_p.h
@@ -302,6 +302,8 @@ public:
 
     bool insert(Compositor::insert_iterator &before, const QV4::Value &object, int groups);
 
+    int adaptorModelCount() const;
+
     static void group_append(QQmlListProperty<QQmlDelegateModelGroup> *property, QQmlDelegateModelGroup *group);
     static int group_count(QQmlListProperty<QQmlDelegateModelGroup> *property);
     static QQmlDelegateModelGroup *group_at(QQmlListProperty<QQmlDelegateModelGroup> *property, int index);
@@ -334,6 +336,7 @@ public:
     bool m_transaction : 1;
     bool m_incubatorCleanupScheduled : 1;
     bool m_waitingToFetchMore : 1;
+    bool m_useFirstColumnOnly : 1;
 
     union {
         struct {
diff --git a/src/quick/items/qquicktableview.cpp b/src/quick/items/qquicktableview.cpp
index 8c092c5894..bcdc06a783 100644
--- a/src/quick/items/qquicktableview.cpp
+++ b/src/quick/items/qquicktableview.cpp
@@ -42,6 +42,7 @@
 
 #include <QtCore/qtimer.h>
 #include <QtQml/private/qqmldelegatemodel_p.h>
+#include <QtQml/private/qqmldelegatemodel_p_p.h>
 #include <QtQml/private/qqmlincubator_p.h>
 #include <QtQml/private/qqmlchangeset_p.h>
 #include <QtQml/qqmlinfo.h>
@@ -1392,6 +1393,7 @@ void QQuickTableView::setModel(const QVariant &newModel)
     } else {
         if (!d->delegateModel)
             d->createWrapperModel();
+        QQmlDelegateModelPrivate::get(d->delegateModel)->m_useFirstColumnOnly = false;
         d->delegateModel->setModel(effectiveModelVariant);
     }
 
diff --git a/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp b/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp
index c1daddb561..5d6708a765 100644
--- a/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp
+++ b/tests/auto/quick/qquicklistview/tst_qquicklistview.cpp
@@ -118,6 +118,7 @@ private slots:
     void noCurrentIndex();
     void keyNavigation();
     void keyNavigation_data();
+    void checkCountForMultiColumnModels();
     void enforceRange();
     void enforceRange_withoutHighlight();
     void spacing();
@@ -1855,6 +1856,38 @@ void tst_QQuickListView::swapWithFirstItem()
     delete testObject;
 }
 
+void tst_QQuickListView::checkCountForMultiColumnModels()
+{
+    // Check that a list view will only load items for the first
+    // column, even if the model reports that it got several columns.
+    // We test this since QQmlDelegateModel has been changed to
+    // also understand multi-column models, but this should not affect ListView.
+    QScopedPointer<QQuickView> window(createView());
+
+    const int rowCount = 10;
+    const int columnCount = 10;
+
+    QaimModel model;
+    model.columns = columnCount;
+    for (int i = 0; i < rowCount; i++)
+        model.addItem("Item" + QString::number(i), "");
+
+    QQmlContext *ctxt = window->rootContext();
+    ctxt->setContextProperty("testModel", &model);
+
+    QScopedPointer<TestObject> testObject(new TestObject);
+    ctxt->setContextProperty("testObject", testObject.data());
+
+    window->setSource(testFileUrl("listviewtest.qml"));
+    window->show();
+    QVERIFY(QTest::qWaitForWindowExposed(window.data()));
+
+    QQuickListView *listview = findItem<QQuickListView>(window->rootObject(), "list");
+    QTRY_VERIFY(listview != nullptr);
+
+    QCOMPARE(listview->count(), rowCount);
+}
+
 void tst_QQuickListView::enforceRange()
 {
     QScopedPointer<QQuickView> window(createView());
diff --git a/tests/auto/quick/shared/viewtestutil.cpp b/tests/auto/quick/shared/viewtestutil.cpp
index dc813b9d59..3bfa23173e 100644
--- a/tests/auto/quick/shared/viewtestutil.cpp
+++ b/tests/auto/quick/shared/viewtestutil.cpp
@@ -153,6 +153,12 @@ int QQuickViewTestUtil::QaimModel::rowCount(const QModelIndex &parent) const
     return list.count();
 }
 
+int QQuickViewTestUtil::QaimModel::columnCount(const QModelIndex &parent) const
+{
+    Q_UNUSED(parent);
+    return columns;
+}
+
 QHash<int,QByteArray> QQuickViewTestUtil::QaimModel::roleNames() const
 {
     QHash<int,QByteArray> roles = QAbstractListModel::roleNames();
@@ -174,7 +180,7 @@ QVariant QQuickViewTestUtil::QaimModel::data(const QModelIndex &index, int role)
 
 int QQuickViewTestUtil::QaimModel::count() const
 {
-    return rowCount();
+    return rowCount() * columnCount();
 }
 
 QString QQuickViewTestUtil::QaimModel::name(int index) const
diff --git a/tests/auto/quick/shared/viewtestutil.h b/tests/auto/quick/shared/viewtestutil.h
index b11d5e4859..04e1771ef8 100644
--- a/tests/auto/quick/shared/viewtestutil.h
+++ b/tests/auto/quick/shared/viewtestutil.h
@@ -76,6 +76,7 @@ namespace QQuickViewTestUtil
         QaimModel(QObject *parent=0);
 
         int rowCount(const QModelIndex &parent=QModelIndex()) const;
+        int columnCount(const QModelIndex &parent=QModelIndex()) const;
         QVariant data(const QModelIndex &index, int role=Qt::DisplayRole) const;
         QHash<int,QByteArray> roleNames() const;
 
@@ -104,6 +105,8 @@ namespace QQuickViewTestUtil
 
         using QAbstractListModel::dataChanged;
 
+        int columns = 1;
+
     private:
         QList<QPair<QString,QString> > list;
     };