TableView: use fetchMore() when scrolling to the end of the table

QQmlTableInstanceModel implements canFetchMore and fetchMore functions,
but these are not called at any point in QQuickTableView. This change
checks if additional data can be fetched when atYEndChanged signal is
emitted.

Fixes: QTBUG-78273
Change-Id: I49b41b09d9a218826b34f32cd9fe4724a6097b52
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

6 files changed, 61 insertions, 0 deletions

diff --git a/src/qmlmodels/qqmltableinstancemodel_p.h b/src/qmlmodels/qqmltableinstancemodel_p.h
index ce5a37bc98..1ea5ee7401 100644
--- a/src/qmlmodels/qqmltableinstancemodel_p.h
+++ b/src/qmlmodels/qqmltableinstancemodel_p.h
@@ -103,6 +103,9 @@ public:
 
     bool isValid() const override { return true; }
 
+    bool canFetchMore() const { return m_adaptorModel.canFetchMore(); }
+    void fetchMore() { m_adaptorModel.fetchMore(); }
+
     QVariant model() const;
     void setModel(const QVariant &model);
 
diff --git a/src/quick/items/qquicktableview.cpp b/src/quick/items/qquicktableview.cpp
index 01eb852ecd..89839c8aab 100644
--- a/src/quick/items/qquicktableview.cpp
+++ b/src/quick/items/qquicktableview.cpp
@@ -2314,6 +2314,7 @@ void QQuickTableViewPrivate::syncSyncView()
 
 void QQuickTableViewPrivate::connectToModel()
 {
+    Q_Q(QQuickTableView);
     Q_TABLEVIEW_ASSERT(model, "");
 
     QObjectPrivate::connect(model, &QQmlInstanceModel::createdItem, this, &QQuickTableViewPrivate::itemCreatedCallback);
@@ -2323,6 +2324,8 @@ void QQuickTableViewPrivate::connectToModel()
         const auto tm = tableModel.data();
         QObjectPrivate::connect(tm, &QQmlTableInstanceModel::itemPooled, this, &QQuickTableViewPrivate::itemPooledCallback);
         QObjectPrivate::connect(tm, &QQmlTableInstanceModel::itemReused, this, &QQuickTableViewPrivate::itemReusedCallback);
+        // Connect atYEndChanged to a function that fetches data if more is available
+        QObjectPrivate::connect(q, &QQuickTableView::atYEndChanged, this, &QQuickTableViewPrivate::fetchMoreData);
     }
 
     if (auto const aim = model->abstractItemModel()) {
@@ -2346,6 +2349,7 @@ void QQuickTableViewPrivate::connectToModel()
 
 void QQuickTableViewPrivate::disconnectFromModel()
 {
+    Q_Q(QQuickTableView);
     Q_TABLEVIEW_ASSERT(model, "");
 
     QObjectPrivate::disconnect(model, &QQmlInstanceModel::createdItem, this, &QQuickTableViewPrivate::itemCreatedCallback);
@@ -2355,6 +2359,7 @@ void QQuickTableViewPrivate::disconnectFromModel()
         const auto tm = tableModel.data();
         QObjectPrivate::disconnect(tm, &QQmlTableInstanceModel::itemPooled, this, &QQuickTableViewPrivate::itemPooledCallback);
         QObjectPrivate::disconnect(tm, &QQmlTableInstanceModel::itemReused, this, &QQuickTableViewPrivate::itemReusedCallback);
+        QObjectPrivate::disconnect(q, &QQuickTableView::atYEndChanged, this, &QQuickTableViewPrivate::fetchMoreData);
     }
 
     if (auto const aim = model->abstractItemModel()) {
@@ -2436,6 +2441,14 @@ void QQuickTableViewPrivate::layoutChangedCallback(const QList<QPersistentModelI
     scheduleRebuildTable(RebuildOption::ViewportOnly);
 }
 
+void QQuickTableViewPrivate::fetchMoreData()
+{
+    if (tableModel && tableModel->canFetchMore()) {
+        tableModel->fetchMore();
+        scheduleRebuildTable(RebuildOption::ViewportOnly);
+    }
+}
+
 void QQuickTableViewPrivate::modelResetCallback()
 {
     scheduleRebuildTable(RebuildOption::All);
diff --git a/src/quick/items/qquicktableview_p_p.h b/src/quick/items/qquicktableview_p_p.h
index 5f53420506..ec043f5e7e 100644
--- a/src/quick/items/qquicktableview_p_p.h
+++ b/src/quick/items/qquicktableview_p_p.h
@@ -426,6 +426,8 @@ public:
     void setLocalViewportY(qreal contentY);
     void syncViewportPosRecursive();
 
+    void fetchMoreData();
+
     void _q_componentFinalized();
     void registerCallbackWhenBindingsAreEvaluated();
 
diff --git a/tests/auto/quick/qquicktableview/qquicktableview.pro b/tests/auto/quick/qquicktableview/qquicktableview.pro
index da0c0b01d0..735c728fc6 100644
--- a/tests/auto/quick/qquicktableview/qquicktableview.pro
+++ b/tests/auto/quick/qquicktableview/qquicktableview.pro
@@ -13,3 +13,5 @@ TESTDATA = data/*
 
 QT += core-private gui-private qml-private quick-private testlib qmlmodels-private
 
+DISTFILES +=
+
diff --git a/tests/auto/quick/qquicktableview/testmodel.h b/tests/auto/quick/qquicktableview/testmodel.h
index 0243158bda..2697b1e801 100644
--- a/tests/auto/quick/qquicktableview/testmodel.h
+++ b/tests/auto/quick/qquicktableview/testmodel.h
@@ -46,6 +46,13 @@ public:
         , m_columns(columns)
     {}
 
+    TestModel(int rows, int columns, bool dataCanBeFetched, QObject *parent = nullptr)
+        : QAbstractTableModel(parent)
+          , m_rows(rows)
+          , m_columns(columns)
+          , m_dataCanBeFetched(dataCanBeFetched)
+    {}
+
     int rowCount(const QModelIndex & = QModelIndex()) const override { return m_rows; }
     void setRowCount(int count) { beginResetModel(); m_rows = count; emit rowCountChanged(); endResetModel(); }
 
@@ -141,6 +148,12 @@ public:
         return true;
     }
 
+    bool canFetchMore(const QModelIndex &parent) const override
+    {
+        Q_UNUSED(parent)
+        return m_dataCanBeFetched;
+    }
+
     void swapRows(int row1, int row2)
     {
         layoutAboutToBeChanged();
@@ -152,6 +165,12 @@ public:
         layoutChanged();
     }
 
+    void fetchMore(const QModelIndex &parent) override
+    {
+        Q_UNUSED(parent)
+        addRow(m_rows - 1);
+    }
+
     void clear() {
         beginResetModel();
         m_rows = 0;
@@ -172,6 +191,7 @@ signals:
 private:
     int m_rows = 0;
     int m_columns = 0;
+    bool m_dataCanBeFetched = false;
     QHash<int, QString> modelData;
 };
 
diff --git a/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp b/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp
index 0117267429..7037e516fd 100644
--- a/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp
+++ b/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp
@@ -175,6 +175,7 @@ private slots:
     void checkSyncView_differentSizedModels();
     void checkSyncView_connect_late_data();
     void checkSyncView_connect_late();
+    void checkThatFetchMoreIsCalledWhenScrolledToTheEndOfTable();
 };
 
 tst_QQuickTableView::tst_QQuickTableView()
@@ -2676,7 +2677,27 @@ void tst_QQuickTableView::checkSyncView_connect_late()
     QCOMPARE(tableViewVPrivate->loadedTableOuterRect.left(), 0);
 
     QCOMPARE(tableViewHVPrivate->loadedTableOuterRect, tableViewPrivate->loadedTableOuterRect);
+}
+
+void tst_QQuickTableView::checkThatFetchMoreIsCalledWhenScrolledToTheEndOfTable()
+{
+    LOAD_TABLEVIEW("plaintableview.qml");
+
+    auto model = TestModelAsVariant(5, 5, true);
+    tableView->setModel(model);
+    WAIT_UNTIL_POLISHED;
+
+    QCOMPARE(tableView->rows(), 5);
+    QCOMPARE(tableView->columns(), 5);
+
+    // Flick table out of view on top
+    tableView->setContentX(0);
+    tableView->setContentY(-tableView->height() - 10);
+    tableView->polish();
+    WAIT_UNTIL_POLISHED;
 
+    QCOMPARE(tableView->rows(), 6);
+    QCOMPARE(tableView->columns(), 5);
 }
 
 QTEST_MAIN(tst_QQuickTableView)