Support for focus scopes: QGraphicsItem::ItemIsFocusScope.

This feature is essential for Declarative UI, but does not add much
value for C++ developers. A FocusScope provides a stack of focused
widgets, and it ensures that the topmost item on the stack has
focus if any of the items in the stack gains focus. When the topmost
loses focus, focus is passed to the "parent" focus scope, and so on.

You can get almost the same behavior using panels (ItemIsPanel),
except panels impose other behavior, like stopping clickfocus
propagation, and stopping event propagation in general. In a QML
world you would typically use FocusScope for controlling focus
locally, and panels when you need to maintain separate focus stacks.

Reviewed-by: akennedy

1 files changed, 89 insertions, 0 deletions

diff --git a/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp b/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp
index 6b5e4bb..0744fa5 100644
--- a/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp
+++ b/tests/auto/qgraphicsitem/tst_qgraphicsitem.cpp
@@ -294,6 +294,7 @@ private slots:
     void activationOnShowHide();
     void moveWhileDeleting();
     void ensureDirtySceneTransform();
+    void focusScope();
 
     // task specific tests below me
     void task141694_textItemEnsureVisible();
@@ -8245,5 +8246,93 @@ void tst_QGraphicsItem::ensureDirtySceneTransform()
     QCOMPARE(child3->sceneTransform(), QTransform::fromTranslate(-80, -80));
 }
 
+void tst_QGraphicsItem::focusScope()
+{
+    // ItemIsFocusScope is an internal feature (for now).
+    QGraphicsScene scene;
+
+    QGraphicsRectItem *scope3 = new QGraphicsRectItem;
+    scope3->setData(0, "scope3");
+    scope3->setFlags(QGraphicsItem::ItemIsFocusable | QGraphicsItem::ItemIsFocusScope);
+    scope3->setFocus();
+    QVERIFY(!scope3->focusScopeItem());
+    QCOMPARE(scope3->focusItem(), (QGraphicsItem *)scope3);
+
+    QGraphicsRectItem *scope2 = new QGraphicsRectItem;
+    scope2->setData(0, "scope2");
+    scope2->setFlags(QGraphicsItem::ItemIsFocusable | QGraphicsItem::ItemIsFocusScope);
+    scope2->setFocus();
+    QVERIFY(!scope2->focusScopeItem());
+    scope3->setParentItem(scope2);
+    QCOMPARE(scope2->focusScopeItem(), (QGraphicsItem *)scope3);
+    QCOMPARE(scope2->focusItem(), (QGraphicsItem *)scope3);
+
+    QGraphicsRectItem *scope1 = new QGraphicsRectItem;
+    scope1->setData(0, "scope1");
+    scope1->setFlags(QGraphicsItem::ItemIsFocusable | QGraphicsItem::ItemIsFocusScope);
+    scope1->setFocus();
+    QVERIFY(!scope1->focusScopeItem());
+    scope2->setParentItem(scope1);
+
+    QCOMPARE(scope1->focusItem(), (QGraphicsItem *)scope3);
+    QCOMPARE(scope2->focusItem(), (QGraphicsItem *)scope3);
+    QCOMPARE(scope3->focusItem(), (QGraphicsItem *)scope3);
+    QCOMPARE(scope1->focusScopeItem(), (QGraphicsItem *)scope2);
+    QCOMPARE(scope2->focusScopeItem(), (QGraphicsItem *)scope3);
+    QCOMPARE(scope3->focusScopeItem(), (QGraphicsItem *)0);
+
+    scene.addItem(scope1);
+
+    QEvent windowActivate(QEvent::WindowActivate);
+    qApp->sendEvent(&scene, &windowActivate);
+    scene.setFocus();
+
+    QCOMPARE(scope1->focusItem(), (QGraphicsItem *)scope3);
+    QCOMPARE(scope2->focusItem(), (QGraphicsItem *)scope3);
+    QCOMPARE(scope3->focusItem(), (QGraphicsItem *)scope3);
+    QCOMPARE(scope1->focusScopeItem(), (QGraphicsItem *)scope2);
+    QCOMPARE(scope2->focusScopeItem(), (QGraphicsItem *)scope3);
+    QCOMPARE(scope3->focusScopeItem(), (QGraphicsItem *)0);
+
+    QVERIFY(scope3->hasFocus());
+
+    scope3->hide();
+    QVERIFY(scope2->hasFocus());
+    scope2->hide();
+    QVERIFY(scope1->hasFocus());
+    scope2->show();
+    QVERIFY(scope2->hasFocus());
+    scope3->show();
+    QVERIFY(scope3->hasFocus());
+    scope1->hide();
+    QVERIFY(!scope3->hasFocus());
+    scope1->show();
+    QVERIFY(scope3->hasFocus());
+    scope3->clearFocus();
+    QVERIFY(scope2->hasFocus());
+    scope2->clearFocus();
+    QVERIFY(scope1->hasFocus());
+    scope2->hide();
+    scope2->show();
+    QVERIFY(!scope2->hasFocus());
+    QVERIFY(scope3->hasFocus());
+
+    QGraphicsRectItem *rect4 = new QGraphicsRectItem;
+    rect4->setData(0, "rect4");
+    rect4->setParentItem(scope3);
+
+    QGraphicsRectItem *rect5 = new QGraphicsRectItem;
+    rect5->setData(0, "rect5");
+    rect5->setFlags(QGraphicsItem::ItemIsFocusable | QGraphicsItem::ItemIsFocusScope);
+    rect5->setFocus();
+    rect5->setParentItem(rect4);
+    QCOMPARE(scope3->focusScopeItem(), (QGraphicsItem *)rect5);
+    QVERIFY(rect5->hasFocus());
+
+    rect4->setParentItem(0);
+    QCOMPARE(scope3->focusScopeItem(), (QGraphicsItem *)0);
+    QVERIFY(!scope3->hasFocus());
+}
+
 QTEST_MAIN(tst_QGraphicsItem)
 #include "tst_qgraphicsitem.moc"