QQuickTableView: add function: itemAtCell(const QPoint)

Add a function to the API to let the application get
the item loaded for a specific cell.

[ChangeLog][TableView] A function 'itemAtCell()' has now
been added to let the application get the delegate
item loaded for a specific cell.

Change-Id: Ie84ef44ea2a0a901487812c4d611b98d4c86ee22
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

3 files changed, 71 insertions, 0 deletions

diff --git a/src/quick/items/qquicktableview.cpp b/src/quick/items/qquicktableview.cpp
index 28a5dee681..3548d20706 100644
--- a/src/quick/items/qquicktableview.cpp
+++ b/src/quick/items/qquicktableview.cpp
@@ -425,6 +425,23 @@
 */
 
 /*!
+    \qmlmethod Item QtQuick::TableView::itemAtCell(point cell)
+
+    Returns the delegate item at \a cell if loaded, otherwise \c null.
+
+    \note only the items that are visible in the view are normally loaded.
+    As soon as a cell is flicked out of the view, the item inside will
+    either be unloaded or placed in the recycle pool. As such, the return
+    value should never be stored.
+*/
+
+/*!
+    \qmlmethod Item QtQuick::TableView::itemAtCell(int column, int row)
+
+    Convenience for calling \code itemAtCell(Qt.point(column, row)) \endcode
+*/
+
+/*!
     \qmlattachedproperty TableView QtQuick::TableView::view
 
     This attached property holds the view that manages the delegate instance.
@@ -3122,6 +3139,20 @@ void QQuickTableView::positionViewAtColumn(int column, Qt::Alignment alignment,
                             QQuickTableViewPrivate::RebuildOption::PositionViewAtColumn);
 }
 
+QQuickItem *QQuickTableView::itemAtCell(const QPoint &cell) const
+{
+    Q_D(const QQuickTableView);
+    const int modelIndex = d->modelIndexAtCell(cell);
+    if (!d->loadedItems.contains(modelIndex))
+        return nullptr;
+    return d->loadedItems.value(modelIndex)->item;
+}
+
+QQuickItem *QQuickTableView::itemAtCell(int column, int row) const
+{
+    return itemAtCell(QPoint(column, row));
+}
+
 void QQuickTableView::forceLayout()
 {
     d_func()->forceLayout();
diff --git a/src/quick/items/qquicktableview_p.h b/src/quick/items/qquicktableview_p.h
index 387cc5d51d..e377f7da65 100644
--- a/src/quick/items/qquicktableview_p.h
+++ b/src/quick/items/qquicktableview_p.h
@@ -127,6 +127,8 @@ public:
     Q_INVOKABLE void positionViewAtCell(int column, int row, Qt::Alignment alignment, const QPointF &offset = QPointF());
     Q_INVOKABLE void positionViewAtRow(int row, Qt::Alignment alignment, qreal offset = 0);
     Q_INVOKABLE void positionViewAtColumn(int column, Qt::Alignment alignment, qreal offset = 0);
+    Q_INVOKABLE QQuickItem *itemAtCell(const QPoint &cell) const;
+    Q_INVOKABLE QQuickItem *itemAtCell(int column, int row) const;
 
     static QQuickTableViewAttached *qmlAttachedProperties(QObject *);
 
diff --git a/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp b/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp
index e0917cbea9..679ced17d7 100644
--- a/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp
+++ b/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp
@@ -182,6 +182,8 @@ private slots:
     void positionViewAtRow();
     void positionViewAtColumn_data();
     void positionViewAtColumn();
+    void itemAtCell_data();
+    void itemAtCell();
 };
 
 tst_QQuickTableView::tst_QQuickTableView()
@@ -2954,6 +2956,42 @@ void tst_QQuickTableView::positionViewAtColumn()
     }
 }
 
+void tst_QQuickTableView::itemAtCell_data()
+{
+    QTest::addColumn<QPoint>("cell");
+    QTest::addColumn<bool>("shouldExist");
+
+    QTest::newRow("0, 0") << QPoint(0, 0) << true;
+    QTest::newRow("0, 4") << QPoint(0, 4) << true;
+    QTest::newRow("4, 0") << QPoint(4, 0) << true;
+    QTest::newRow("4, 4") << QPoint(4, 4) << true;
+    QTest::newRow("30, 30") << QPoint(30, 30) << false;
+    QTest::newRow("-1, -1") << QPoint(-1, -1) << false;
+}
+
+void tst_QQuickTableView::itemAtCell()
+{
+    QFETCH(QPoint, cell);
+    QFETCH(bool, shouldExist);
+
+    LOAD_TABLEVIEW("plaintableview.qml");
+    auto model = TestModelAsVariant(100, 100);
+    tableView->setModel(model);
+
+    WAIT_UNTIL_POLISHED;
+
+    const auto item = tableView->itemAtCell(cell);
+    if (shouldExist) {
+        const auto context = qmlContext(item);
+        const int contextRow = context->contextProperty("row").toInt();
+        const int contextColumn = context->contextProperty("column").toInt();
+        QCOMPARE(contextColumn, cell.x());
+        QCOMPARE(contextRow, cell.y());
+    } else {
+        QVERIFY(!item);
+    }
+}
+
 QTEST_MAIN(tst_QQuickTableView)
 
 #include "tst_qquicktableview.moc"