Itemviews: add ItemIsUserTristate flag

ItemIsTristate is now again purely for enabling the automatic management
of the check state of QTreeWidgetItems, while ItemIsUserTristate is
separate from that and lets the user select the three states manually.

This restores the original behavior of ItemIsTristate for QTreeWidgetItems,
which got broken by letting the user cycle through the states too.

[ChangeLog][QtWidgets][QTreeWidget] Restored Qt 5.1 behavior of
QTreeWidgetItems with ItemIsTristate to enable automatic management
of the check state. User-editable tristate checkboxes are now enabled
by setting the new flag ItemIsUserTristate.

Task-number: QTBUG-40060
Change-Id: I341f5e983804d3b4f27982520bb6647f3014cccc
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Reviewed-by: Jarek Kobus <jaroslaw.kobus@theqtcompany.com>

2 files changed, 64 insertions, 1 deletions

diff --git a/tests/auto/widgets/itemviews/qitemdelegate/tst_qitemdelegate.cpp b/tests/auto/widgets/itemviews/qitemdelegate/tst_qitemdelegate.cpp
index 0ecb1d1af4..0d1f11c1b5 100644
--- a/tests/auto/widgets/itemviews/qitemdelegate/tst_qitemdelegate.cpp
+++ b/tests/auto/widgets/itemviews/qitemdelegate/tst_qitemdelegate.cpp
@@ -1159,7 +1159,7 @@ void tst_QItemDelegate::editorEvent_data()
         << (int)(QEvent::MouseButtonRelease)
         << (int)(Qt::LeftButton)
         << true
-        << (int)(Qt::PartiallyChecked);
+        << (int)(Qt::Checked);
 
     QTest::newRow("partially checked, tristate, release")
         << (int)(Qt::PartiallyChecked)
@@ -1178,6 +1178,33 @@ void tst_QItemDelegate::editorEvent_data()
         << (int)(Qt::LeftButton)
         << true
         << (int)(Qt::Unchecked);
+
+    QTest::newRow("unchecked, user-tristate, release")
+        << (int)(Qt::Unchecked)
+        << (int)(defaultFlags | Qt::ItemIsUserTristate)
+        << true
+        << (int)(QEvent::MouseButtonRelease)
+        << (int)(Qt::LeftButton)
+        << true
+        << (int)(Qt::PartiallyChecked);
+
+    QTest::newRow("partially checked, user-tristate, release")
+        << (int)(Qt::PartiallyChecked)
+        << (int)(defaultFlags | Qt::ItemIsUserTristate)
+        << true
+        << (int)(QEvent::MouseButtonRelease)
+        << (int)(Qt::LeftButton)
+        << true
+        << (int)(Qt::Checked);
+
+    QTest::newRow("checked, user-tristate, release")
+        << (int)(Qt::Checked)
+        << (int)(defaultFlags | Qt::ItemIsUserTristate)
+        << true
+        << (int)(QEvent::MouseButtonRelease)
+        << (int)(Qt::LeftButton)
+        << true
+        << (int)(Qt::Unchecked);
 }
 
 void tst_QItemDelegate::editorEvent()
diff --git a/tests/auto/widgets/itemviews/qtreewidget/tst_qtreewidget.cpp b/tests/auto/widgets/itemviews/qtreewidget/tst_qtreewidget.cpp
index c1331d62e1..23b6c3e369 100644
--- a/tests/auto/widgets/itemviews/qtreewidget/tst_qtreewidget.cpp
+++ b/tests/auto/widgets/itemviews/qtreewidget/tst_qtreewidget.cpp
@@ -129,6 +129,8 @@ private slots:
     void task245280_sortChildren();
     void task253109_itemHeight();
 
+    void nonEditableTristate();
+
     // QTreeWidgetItem
     void itemOperatorLessThan();
     void addChild();
@@ -3162,6 +3164,40 @@ void tst_QTreeWidget::task217309()
     QVERIFY(item.data(0, Qt::CheckStateRole) == Qt::Checked);
 }
 
+void tst_QTreeWidget::nonEditableTristate()
+{
+    // A tree with checkable items, the parent is tristate
+    QTreeWidget *tree = new QTreeWidget;
+    QTreeWidgetItem *item = new QTreeWidgetItem();
+    tree->insertTopLevelItem(0, item);
+    item->setFlags(item->flags() | Qt::ItemIsTristate);
+    item->setCheckState(0, Qt::Unchecked);
+    QTreeWidgetItem *subitem1 = new QTreeWidgetItem(item);
+    subitem1->setCheckState(0, Qt::Unchecked);
+    QTreeWidgetItem *subitem2 = new QTreeWidgetItem(item);
+    subitem2->setCheckState(0, Qt::Unchecked);
+    QCOMPARE(int(item->checkState(0)), int(Qt::Unchecked));
+    tree->show();
+
+    // Test clicking on the parent item, it should become Checked (not PartiallyChecked)
+    QStyleOptionViewItem option;
+    option.rect = tree->visualRect(tree->model()->index(0, 0));
+    option.state |= QStyle::State_Enabled;
+    option.features |= QStyleOptionViewItem::HasCheckIndicator | QStyleOptionViewItem::HasDisplay;
+    option.checkState = item->checkState(0);
+
+    const int checkMargin = qApp->style()->pixelMetric(QStyle::PM_FocusFrameHMargin, 0, 0) + 1;
+    QPoint pos = qApp->style()->subElementRect(QStyle::SE_ViewItemCheckIndicator, &option, 0).center() + QPoint(checkMargin, 0);
+    QTest::mouseClick(tree->viewport(), Qt::LeftButton, Qt::NoModifier, pos);
+    QCOMPARE(int(item->checkState(0)), int(Qt::Checked));
+
+    // Click again, it should become Unchecked.
+    QTest::mouseClick(tree->viewport(), Qt::LeftButton, Qt::NoModifier, pos);
+    QCOMPARE(int(item->checkState(0)), int(Qt::Unchecked));
+
+    delete tree;
+}
+
 class TreeWidgetItem : public QTreeWidgetItem
 {