QQuickTableView: add a new 'alternatingRows' property

Add a new property 'alternatingRows' that informs the
delegate that it should alternate between rows.
This is merely a hint, the delegate is free
to ignore it. But our own internal delegates, like
TreeViewDelegate, should not.

[ChangeLog][Quick][TableView] Added a new property
'alternatingRows', which is a hint to the delegate
to alternate between rows.

Change-Id: I3f10e7280332b652d393348ff0d71cd73ce6fa4d
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

7 files changed, 66 insertions, 3 deletions

diff --git a/src/quick/items/qquicktableview.cpp b/src/quick/items/qquicktableview.cpp
index ecd302a761..895667b17a 100644
--- a/src/quick/items/qquicktableview.cpp
+++ b/src/quick/items/qquicktableview.cpp
@@ -406,6 +406,29 @@
 */
 
 /*!
+    \qmlproperty bool QtQuick::TableView::alternatingRows
+
+    This property controls whether the background color of the rows should alternate.
+    The default value is style dependent.
+
+    \note This property is only a hint, and might therefore not be
+    respected by custom delegates. It's recommended that a delegate alternates
+    between \c palette.base and \c palette.alternateBase when this hint is
+    \c true, so that the colors can be set from outside of the delegate.
+    For example:
+
+    \code
+    background: Rectangle {
+        color: control.row === control.tableView.currentRow
+               ? control.palette.highlight
+               : (control.tableView.alternatingRows && control.row % 2 !== 0
+               ? control.palette.alternateBase
+               : control.palette.base)
+    }
+    \endcode
+*/
+
+/*!
     \qmlproperty int QtQuick::TableView::leftColumn
 
     This property holds the leftmost column that is currently visible inside the view.
@@ -4896,6 +4919,21 @@ void QQuickTableView::keyPressEvent(QKeyEvent *e)
     }
 }
 
+bool QQuickTableView::alternatingRows() const
+{
+    return d_func()->alternatingRows;
+}
+
+void QQuickTableView::setAlternatingRows(bool alternatingRows)
+{
+    Q_D(QQuickTableView);
+    if (d->alternatingRows == alternatingRows)
+        return;
+
+    d->alternatingRows = alternatingRows;
+    emit alternatingRowsChanged();
+}
+
 class QObjectPrivate;
 class QQuickTableSectionSizeProviderPrivate : public QObjectPrivate {
 public:
diff --git a/src/quick/items/qquicktableview_p.h b/src/quick/items/qquicktableview_p.h
index 0e43020e4b..1299f4b58f 100644
--- a/src/quick/items/qquicktableview_p.h
+++ b/src/quick/items/qquicktableview_p.h
@@ -94,6 +94,7 @@ class Q_QUICK_PRIVATE_EXPORT QQuickTableView : public QQuickFlickable, public QQ
     Q_PROPERTY(bool pointerNavigationEnabled READ pointerNavigationEnabled WRITE setPointerNavigationEnabled NOTIFY pointerNavigationEnabledChanged REVISION(6, 4))
     Q_PROPERTY(int currentRow READ currentRow NOTIFY currentRowChanged REVISION(6, 4) FINAL)
     Q_PROPERTY(int currentColumn READ currentColumn NOTIFY currentColumnChanged REVISION(6, 4) FINAL)
+    Q_PROPERTY(bool alternatingRows READ alternatingRows WRITE setAlternatingRows NOTIFY alternatingRowsChanged REVISION(6, 4) FINAL)
 
     QML_NAMED_ELEMENT(TableView)
     QML_ADDED_IN_VERSION(2, 12)
@@ -168,6 +169,9 @@ public:
     int currentRow() const;
     int currentColumn() const;
 
+    bool alternatingRows() const;
+    void setAlternatingRows(bool alternatingRows);
+
     Q_INVOKABLE void forceLayout();
     Q_INVOKABLE void positionViewAtCell(const QPoint &cell, PositionMode mode, const QPointF &offset = QPointF());
     Q_INVOKABLE void positionViewAtCell(int column, int row, PositionMode mode, const QPointF &offset = QPointF());
@@ -222,6 +226,7 @@ Q_SIGNALS:
     Q_REVISION(6, 4) void pointerNavigationEnabledChanged();
     Q_REVISION(6, 4) void currentRowChanged();
     Q_REVISION(6, 4) void currentColumnChanged();
+    Q_REVISION(6, 4) void alternatingRowsChanged();
 
 protected:
     void geometryChange(const QRectF &newGeometry, const QRectF &oldGeometry) override;
diff --git a/src/quick/items/qquicktableview_p_p.h b/src/quick/items/qquicktableview_p_p.h
index 0563a96bf3..0ef72d8be4 100644
--- a/src/quick/items/qquicktableview_p_p.h
+++ b/src/quick/items/qquicktableview_p_p.h
@@ -290,6 +290,7 @@ public:
     bool animate = true;
     bool keyNavigationEnabled = true;
     bool pointerNavigationEnabled = true;
+    bool alternatingRows = true;
 
     // isTransposed is currently only used by HeaderView.
     // Consider making it public.
diff --git a/src/quickcontrols2/basic/TreeViewDelegate.qml b/src/quickcontrols2/basic/TreeViewDelegate.qml
index 6bd2c5e5c7..af73d96db4 100644
--- a/src/quickcontrols2/basic/TreeViewDelegate.qml
+++ b/src/quickcontrols2/basic/TreeViewDelegate.qml
@@ -81,7 +81,9 @@ T.TreeViewDelegate {
     background: Rectangle {
         color: control.row === control.treeView.currentRow
                ? control.palette.highlight
-               : (control.row % 2 === 0 ? control.palette.base : control.palette.alternateBase)
+               : (control.treeView.alternatingRows && control.row % 2 !== 0
+               ? control.palette.alternateBase
+               : control.palette.base)
     }
 
     contentItem: Label {
diff --git a/src/quickcontrols2/macos/TreeViewDelegate.qml b/src/quickcontrols2/macos/TreeViewDelegate.qml
index 862ff6c440..adc1ee8528 100644
--- a/src/quickcontrols2/macos/TreeViewDelegate.qml
+++ b/src/quickcontrols2/macos/TreeViewDelegate.qml
@@ -49,7 +49,9 @@ NativeStyle.DefaultTreeViewDelegate {
     background: Rectangle {
         color: control.row === control.treeView.currentRow
                ? control.palette.highlight
-               : (control.row % 2 === 0 ? control.palette.base : control.palette.alternateBase)
+               : (control.treeView.alternatingRows && control.row % 2 !== 0
+               ? control.palette.alternateBase
+               : control.palette.base)
         // Ideally we want a rounded background for the whole row, also when
         // there are more than one column. But until Rectangle gains support
         // for corners with individual radii, we simplify it (QTBUG-48774)
diff --git a/src/quicknativestyle/controls/DefaultTreeViewDelegate.qml b/src/quicknativestyle/controls/DefaultTreeViewDelegate.qml
index 86e658824b..765f6d49d3 100644
--- a/src/quicknativestyle/controls/DefaultTreeViewDelegate.qml
+++ b/src/quicknativestyle/controls/DefaultTreeViewDelegate.qml
@@ -79,7 +79,9 @@ T.TreeViewDelegate {
     background: Rectangle {
         color: control.row === control.treeView.currentRow
                ? control.palette.highlight
-               : (control.row % 2 === 0 ? control.palette.base : control.palette.alternateBase)
+               : (control.treeView.alternatingRows && control.row % 2 !== 0
+               ? control.palette.alternateBase
+               : control.palette.base)
     }
 
     contentItem: Label {
diff --git a/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp b/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp
index 2e02e5873d..59a257a7f5 100644
--- a/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp
+++ b/tests/auto/quick/qquicktableview/tst_qquicktableview.cpp
@@ -230,6 +230,7 @@ private slots:
     void selectUsingHomeAndEndKeys();
     void selectUsingPageUpDownKeys();
     void testDeprecatedApi();
+    void alternatingRows();
 };
 
 tst_QQuickTableView::tst_QQuickTableView()
@@ -4948,6 +4949,18 @@ void tst_QQuickTableView::testDeprecatedApi()
     QCOMPARE(tableView->bottomRow(), model.rowCount() - 1);
 }
 
+void tst_QQuickTableView::alternatingRows()
+{
+    // Check that you can set 'alternate'
+    LOAD_TABLEVIEW("plaintableview.qml");
+
+    QVERIFY(tableView->alternatingRows());
+    tableView->setAlternatingRows(false);
+    QVERIFY(!tableView->alternatingRows());
+    tableView->setAlternatingRows(true);
+    QVERIFY(tableView->alternatingRows());
+}
+
 QTEST_MAIN(tst_QQuickTableView)
 
 #include "tst_qquicktableview.moc"