TreeViewDelegate: allow app to add custom pointer handlers

As it stood, it was not possible to add custom pointer handlers
to a TreeViewDelegate, to e.g do an expandRecursive() if using the
right mouse button, or holding down ctrl during a click.

This patch will change this, so that we only perform the default
collapse/expand operations when using a plain left (double)
click, and ignore the event otherwise.

Change-Id: Ifbdf0903158b65c50d0e36e98ab7e48efaa3e3ab
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
(cherry picked from commit 2014101583b89128960f645e57192d1d475767e6)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

3 files changed, 69 insertions, 6 deletions

diff --git a/src/quicktemplates2/qquicktreeviewdelegate.cpp b/src/quicktemplates2/qquicktreeviewdelegate.cpp
index b233020702..1636afbfa1 100644
--- a/src/quicktemplates2/qquicktreeviewdelegate.cpp
+++ b/src/quicktemplates2/qquicktreeviewdelegate.cpp
@@ -216,6 +216,13 @@ void QQuickTreeViewDelegate::mousePressEvent(QMouseEvent *event)
 {
     QQuickAbstractButton::mousePressEvent(event);
 
+    if (event->buttons() != Qt::LeftButton || event->modifiers() != Qt::NoModifier) {
+        // Allow application to add its own pointer handlers that does something
+        // other than plain expand/collapse if e.g holding down modifier keys.
+        event->ignore();
+        return;
+    }
+
     const auto indicator = QQuickAbstractButton::indicator();
     if (indicator && indicator->isVisible()) {
         const auto posInIndicator = mapToItem(indicator, event->position());
diff --git a/tests/auto/quickcontrols2/qquicktreeviewdelegate/tst_qquicktreeviewdelegate.cpp b/tests/auto/quickcontrols2/qquicktreeviewdelegate/tst_qquicktreeviewdelegate.cpp
index 021628709c..0478c97431 100644
--- a/tests/auto/quickcontrols2/qquicktreeviewdelegate/tst_qquicktreeviewdelegate.cpp
+++ b/tests/auto/quickcontrols2/qquicktreeviewdelegate/tst_qquicktreeviewdelegate.cpp
@@ -89,6 +89,8 @@ private slots:
     void showTreeView();
     void expandAndCollapsUsingDoubleClick();
     void expandAndCollapseClickOnIndicator();
+    void expandAndCollapsUsingNonSupportedButtonAndModifers_data();
+    void expandAndCollapsUsingNonSupportedButtonAndModifers();
     void checkPropertiesRoot();
     void checkPropertiesChildren();
 };
@@ -163,6 +165,57 @@ void tst_qquicktreeviewdelegate::expandAndCollapseClickOnIndicator()
     QCOMPARE(treeViewPrivate->loadedRows.count(), 1);
 }
 
+void tst_qquicktreeviewdelegate::expandAndCollapsUsingNonSupportedButtonAndModifers_data()
+{
+    QTest::addColumn<Qt::MouseButton>("button");
+    QTest::addColumn<Qt::KeyboardModifiers>("modifiers");
+
+    QTest::newRow("left + Qt::ControlModifier") << Qt::LeftButton << Qt::KeyboardModifiers(Qt::ControlModifier);
+    QTest::newRow("left + Qt::ShiftModifier") << Qt::LeftButton << Qt::KeyboardModifiers(Qt::ShiftModifier);
+    QTest::newRow("left + Qt::AltModifier") << Qt::LeftButton << Qt::KeyboardModifiers(Qt::AltModifier);
+    QTest::newRow("left + Qt::MetaModifier") << Qt::LeftButton << Qt::KeyboardModifiers(Qt::MetaModifier);
+    QTest::newRow("left + Qt::ControlModifier + Qt::ShiftModifier") << Qt::LeftButton << (Qt::ShiftModifier | Qt::ControlModifier);
+
+    QTest::newRow("right + Qt::NoModifier") << Qt::RightButton << Qt::KeyboardModifiers(Qt::ControlModifier);
+    QTest::newRow("right + Qt::ControlModifier") << Qt::RightButton << Qt::KeyboardModifiers(Qt::ShiftModifier);
+}
+
+void tst_qquicktreeviewdelegate::expandAndCollapsUsingNonSupportedButtonAndModifers()
+{
+    QFETCH(Qt::MouseButton, button);
+    QFETCH(Qt::KeyboardModifiers, modifiers);
+    // Ensure that we don't expand or collapse the tree if the user is using the right mouse
+    // button, or holding down modifier keys. This "space" is reserved for application specific actions.
+    LOAD_TREEVIEW("unmodified.qml");
+
+    QCOMPARE(treeViewPrivate->loadedRows.count(), 1);
+    const auto item = treeView->itemAtCell(0, 0);
+    QVERIFY(item);
+    const QPoint localPos = QPoint(item->width() / 2, item->height() / 2);
+    const QPoint pos = item->window()->contentItem()->mapFromItem(item, localPos).toPoint();
+    QTest::mouseDClick(item->window(), button, modifiers, pos);
+
+    WAIT_UNTIL_POLISHED;
+
+    QCOMPARE(treeViewPrivate->loadedRows.count(), 1);
+
+    // Expand first row, and ensure we don't collapse it again
+    // if doing a double click together with Qt::CTRL.
+    QTest::mouseDClick(item->window(), Qt::LeftButton, Qt::NoModifier, pos);
+
+    WAIT_UNTIL_POLISHED;
+
+    // We now expect 5 rows, the root pluss it's 4 children
+    QCOMPARE(treeViewPrivate->loadedRows.count(), 5);
+
+    QTest::mouseDClick(item->window(), button, modifiers, pos);
+
+    WAIT_UNTIL_POLISHED;
+
+    // We still expect 5 rows, the root pluss it's 4 children
+    QCOMPARE(treeViewPrivate->loadedRows.count(), 5);
+}
+
 void tst_qquicktreeviewdelegate::checkPropertiesRoot()
 {
     LOAD_TREEVIEW("unmodified.qml");
diff --git a/tests/manual/treeview/sidebyside/data/treeview.qml b/tests/manual/treeview/sidebyside/data/treeview.qml
index 6587e11f6e..0e97e23a96 100644
--- a/tests/manual/treeview/sidebyside/data/treeview.qml
+++ b/tests/manual/treeview/sidebyside/data/treeview.qml
@@ -114,15 +114,18 @@ ApplicationWindow {
         id: testModel
     }
 
-    Rectangle {
-        anchors.fill: parent
-        color: "white"
-        z: -1
-    }
-
     Component {
         id: treeViewDelegate
         TreeViewDelegate {
+            TapHandler {
+                acceptedModifiers: Qt.ControlModifier
+                onTapped: {
+                    if (treeView.isExpanded(row))
+                        treeView.collapseRecursively(row)
+                    else
+                        treeView.expandRecursively(row)
+                }
+            }
         }
     }