Added new convenience readonly visibleChildren property to Item

Change-Id: I5ec541226fabd72c05ce8ccb8bb7e56f6ec7717a
Task-number: 22724
Reviewed-by: Aaron Kennedy <aaron.kennedy@nokia.com>

2 files changed, 204 insertions, 0 deletions

diff --git a/tests/auto/qtquick2/qquickitem2/data/visiblechildren.qml b/tests/auto/qtquick2/qquickitem2/data/visiblechildren.qml
new file mode 100644
index 0000000000..e51eb3551b
--- /dev/null
+++ b/tests/auto/qtquick2/qquickitem2/data/visiblechildren.qml
@@ -0,0 +1,143 @@
+import QtQuick 2.0
+
+Item {
+    id: root
+    width: 400
+    height: 300
+
+    Row {
+        id: row
+        Item { id: item1
+            Item { id: item1_1; visible: true }
+            Item { id: item1_2; visible: true }
+        }
+        Item { id: item2 }
+        Item { id: item3
+            Item { id: item3_1; visible: false }
+            Item { id: item3_2; visible: false }
+        }
+        Item { id: item4; visible: false
+            Item { id: item4_1          // implicitly invisible
+                Item { id: item4_1_1 }  // implicitly invisible
+                Item { id: item4_1_2 }  // implicitly invisible
+            }
+        }
+    }
+
+    property int row_changeEventCalls: 0
+    property int item1_changeEventCalls: 0
+    property int item2_changeEventCalls: 0
+    property int item3_changeEventCalls: 0
+    property int item4_1_changeEventCalls: 0
+    property int item4_1_1_changeEventCalls: 0
+    Connections { target: row; onVisibleChildrenChanged: row_changeEventCalls++ }
+    Connections { target: item1; onVisibleChildrenChanged: item1_changeEventCalls++ }
+    Connections { target: item2; onVisibleChildrenChanged: item2_changeEventCalls++ }
+    Connections { target: item3; onVisibleChildrenChanged: item3_changeEventCalls++ }
+    Connections { target: item4_1; onVisibleChildrenChanged: item4_1_changeEventCalls++ }
+    Connections { target: item4_1_1; onVisibleChildrenChanged: item4_1_1_changeEventCalls++ }
+
+    // Make sure there are three visible children and no signals fired yet
+    property bool test1_1: row.visibleChildren.length == 3
+    property bool test1_2: row.visibleChildren[0] == item1 && row.visibleChildren[1] == item2 && row.visibleChildren[2] == item3
+    property bool test1_3: row_changeEventCalls == 0
+    property bool test1_4: item1_changeEventCalls == 0 && item2_changeEventCalls == 0 && item3_changeEventCalls == 0
+
+    // Next test
+    function hideFirstAndLastRowChild() {
+        item1.visible = false;
+        item3.visible = false;
+    }
+
+    // Make sure row is signaled twice and item1 only once, and item3 not at all, and that item2 is the visible child
+    property bool test2_1: row.visibleChildren.length == 1
+    property bool test2_2: row.visibleChildren[0] == item2
+    property bool test2_3: row_changeEventCalls == 2
+    property bool test2_4: item1_changeEventCalls == 1 && item2_changeEventCalls == 0 && item3_changeEventCalls == 0
+
+    // Next test
+    function showLastRowChildsLastChild() {
+        item3_2.visible = true;
+    }
+
+    // Make sure item3_changeEventCalls is not signaled
+    property bool test3_1: row.visibleChildren.length == 1
+    property bool test3_2: row.visibleChildren[0] == item2
+    property bool test3_3: row_changeEventCalls == 2
+    property bool test3_4: item1_changeEventCalls == 1 && item2_changeEventCalls == 0 && item3_changeEventCalls == 0
+
+    // Next test
+    function showLastRowChild() {
+        item3.visible = true;
+    }
+
+    // Make sure row and item3 are signaled
+    property bool test4_1: row.visibleChildren.length == 2
+    property bool test4_2: row.visibleChildren[0] == item2 && row.visibleChildren[1] == item3
+    property bool test4_3: row_changeEventCalls == 3
+    property bool test4_4: item1_changeEventCalls == 1 && item2_changeEventCalls == 0 && item3_changeEventCalls == 1
+
+    // Next test
+    function tryWriteToReadonlyVisibleChildren() {
+        var foo = fooComponent.createObject(root);
+        if (Qt.isQtObject(foo) && foo.children.length == 3 && foo.visibleChildren.length == 3) {
+            test5_1 = true;
+        }
+
+        foo.visibleChildren.length = 10;    // make sure this has no effect
+        test5_1 = (foo.visibleChildren.length == 3);
+        delete foo;
+    }
+
+    Component {
+        id: fooComponent
+        Item {
+            children: [ Item {},Item {},Item {} ]
+            visibleChildren: [ Item {} ]
+        }
+    }
+
+    // Make sure visibleChildren.length is 3 and stays that way
+    property bool test5_1: false
+
+    // Next test
+    function reparentVisibleItem3() {
+        item3.parent = hiddenItem;  // item3 has one visible children
+    }
+
+    Item { id: hiddenItem; visible: false }
+
+    property bool test6_1: row.visibleChildren.length == 1 && row_changeEventCalls == 4
+    property bool test6_2: item3_changeEventCalls == 2
+    property bool test6_3: item3.visible == false
+
+    // Next test
+
+    property bool test6_4: item4_1.visible == false && item4_1_changeEventCalls == 0
+
+    function reparentImlicitlyInvisibleItem4_1() {
+        item4_1.parent = visibleItem;
+    }
+
+    Item { id: visibleItem; visible: true }
+    property int visibleItem_changeEventCalls: 0
+    Connections { target: visibleItem; onVisibleChildrenChanged: visibleItem_changeEventCalls++ }
+
+
+    // Make sure that an item with implictly invisible children will be signaled when reparented to a visible parent
+    property bool test7_1: row.visibleChildren.length == 1 && row_changeEventCalls == 4
+    property bool test7_2: item4_1.visible == true
+    property bool test7_3: item4_1_changeEventCalls == 1
+    property bool test7_4: visibleItem_changeEventCalls == 1
+
+
+
+    // FINALLY make sure nothing has changes while we weren't paying attention
+
+    property bool test8_1: row.visibleChildren.length == 1 && row.visibleChildren[0] == item2 && row_changeEventCalls == 4
+    property bool test8_2: item1_changeEventCalls == 1 && item1.visible == false
+    property bool test8_3: item2_changeEventCalls == 0 && item2.visible == true
+    property bool test8_4: item3_changeEventCalls == 2 && item3.visible == false
+    property bool test8_5: item4_1_1_changeEventCalls == 0 && item4_1_1.visible == true
+
+}
diff --git a/tests/auto/qtquick2/qquickitem2/tst_qquickitem.cpp b/tests/auto/qtquick2/qquickitem2/tst_qquickitem.cpp
index f6a7b0c9c3..c26fc94178 100644
--- a/tests/auto/qtquick2/qquickitem2/tst_qquickitem.cpp
+++ b/tests/auto/qtquick2/qquickitem2/tst_qquickitem.cpp
@@ -85,6 +85,7 @@ private slots:
     void transformCrash();
     void implicitSize();
     void qtbug_16871();
+    void visibleChildren();
 private:
     QDeclarativeEngine engine;
 };
@@ -1246,6 +1247,66 @@ void tst_QQuickItem::qtbug_16871()
     delete o;
 }
 
+
+void tst_QQuickItem::visibleChildren()
+{
+    QQuickView *canvas = new QQuickView(0);
+    canvas->setSource(testFileUrl("visiblechildren.qml"));
+    canvas->show();
+
+    QQuickItem *root = qobject_cast<QQuickItem*>(canvas->rootObject());
+    QVERIFY(root);
+
+    QCOMPARE(root->property("test1_1").toBool(), true);
+    QCOMPARE(root->property("test1_2").toBool(), true);
+    QCOMPARE(root->property("test1_3").toBool(), true);
+    QCOMPARE(root->property("test1_4").toBool(), true);
+
+    QMetaObject::invokeMethod(root, "hideFirstAndLastRowChild");
+    QCOMPARE(root->property("test2_1").toBool(), true);
+    QCOMPARE(root->property("test2_2").toBool(), true);
+    QCOMPARE(root->property("test2_3").toBool(), true);
+    QCOMPARE(root->property("test2_4").toBool(), true);
+
+    QMetaObject::invokeMethod(root, "showLastRowChildsLastChild");
+    QCOMPARE(root->property("test3_1").toBool(), true);
+    QCOMPARE(root->property("test3_2").toBool(), true);
+    QCOMPARE(root->property("test3_3").toBool(), true);
+    QCOMPARE(root->property("test3_4").toBool(), true);
+
+    QMetaObject::invokeMethod(root, "showLastRowChild");
+    QCOMPARE(root->property("test4_1").toBool(), true);
+    QCOMPARE(root->property("test4_2").toBool(), true);
+    QCOMPARE(root->property("test4_3").toBool(), true);
+    QCOMPARE(root->property("test4_4").toBool(), true);
+
+    QString warning1 = testFileUrl("visiblechildren.qml").toString() + ":96:32: QML Item: QQuickItem: visibleChildren property is readonly and cannot be assigned to.";
+    QTest::ignoreMessage(QtWarningMsg, qPrintable(warning1));
+    QMetaObject::invokeMethod(root, "tryWriteToReadonlyVisibleChildren");
+    QCOMPARE(root->property("test5_1").toBool(), true);
+
+    QMetaObject::invokeMethod(root, "reparentVisibleItem3");
+    QCOMPARE(root->property("test6_1").toBool(), true);
+    QCOMPARE(root->property("test6_2").toBool(), true);
+    QCOMPARE(root->property("test6_3").toBool(), true);
+    QCOMPARE(root->property("test6_4").toBool(), true);
+
+    QMetaObject::invokeMethod(root, "reparentImlicitlyInvisibleItem4_1");
+    QCOMPARE(root->property("test7_1").toBool(), true);
+    QCOMPARE(root->property("test7_2").toBool(), true);
+    QCOMPARE(root->property("test7_3").toBool(), true);
+    QCOMPARE(root->property("test7_4").toBool(), true);
+
+    // FINALLY TEST THAT EVERYTHING IS AS EXPECTED
+    QCOMPARE(root->property("test8_1").toBool(), true);
+    QCOMPARE(root->property("test8_2").toBool(), true);
+    QCOMPARE(root->property("test8_3").toBool(), true);
+    QCOMPARE(root->property("test8_4").toBool(), true);
+    QCOMPARE(root->property("test8_5").toBool(), true);
+
+    delete canvas;
+}
+
 QTEST_MAIN(tst_QQuickItem)
 
 #include "tst_qquickitem.moc"