QStackedLayout: Fix crash when focus widget is destroyed in hide()

We also have to make sure that when moving back to a page
that has a focusWidget(), the focus should go to the focusWidget()

Task-number: QTBUG-18242

Change-Id: Ibfa7d6361c1a456480b2f1584a88ef4c4f405709
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
(cherry picked from qtbase/18f9eb797bffe8626f1edeca3c88f80dae0da8d7)

1 files changed, 89 insertions, 0 deletions

diff --git a/tests/auto/qstackedwidget/tst_qstackedwidget.cpp b/tests/auto/qstackedwidget/tst_qstackedwidget.cpp
index ba8171cd06..c3b6e23f3f 100644
--- a/tests/auto/qstackedwidget/tst_qstackedwidget.cpp
+++ b/tests/auto/qstackedwidget/tst_qstackedwidget.cpp
@@ -47,6 +47,8 @@
 #include <qstackedwidget.h>
 #include <qpushbutton.h>
 #include <QHBoxLayout>
+#include <qlineedit.h>
+#include "../../shared/util.h"
 
 //TESTED_CLASS=
 //TESTED_FILES=
@@ -62,6 +64,7 @@ public:
 private slots:
     void getSetCheck();
     void testMinimumSize();
+    void dynamicPages();
 };
 
 tst_QStackedWidget::tst_QStackedWidget()
@@ -120,5 +123,91 @@ void tst_QStackedWidget::getSetCheck()
     delete var2;
 }
 
+// QTBUG-18242, a widget that deletes its children in hideEvent().
+// This caused a crash in QStackedLayout::setCurrentIndex() since
+// the focus widget was destroyed while hiding the previous page.
+class TestPage : public QWidget
+{
+public:
+    TestPage (bool staticWidgets = false) : QWidget(0), m_staticWidgets(staticWidgets)
+    {
+        new QVBoxLayout (this);
+    }
+
+    ~TestPage() {
+        destroyWidgets();
+    }
+
+    void setN(int n)
+    {
+        m_n = n;
+        if (m_staticWidgets)
+            createWidgets();
+    }
+
+    virtual void showEvent (QShowEvent *)
+    {
+        if (!m_staticWidgets)
+            createWidgets();
+    }
+
+    virtual void hideEvent (QHideEvent *)
+    {
+        if (!m_staticWidgets)
+            destroyWidgets();
+    }
+
+private:
+    void createWidgets() {
+        for (int i = 0; i < m_n; ++i) {
+            QLineEdit *le = new QLineEdit(this);
+            le->setObjectName(QString::fromLatin1("lineEdit%1").arg(i));
+            layout ()->addWidget(le);
+            m_les << le;
+        }
+    }
+
+    void destroyWidgets()
+    {
+        qDeleteAll(m_les);
+        m_les.clear ();
+    }
+
+    int m_n;
+    const bool m_staticWidgets;
+    QList<QLineEdit*> m_les;
+};
+
+void tst_QStackedWidget::dynamicPages()
+{
+    QStackedWidget *sw = new QStackedWidget;
+
+    TestPage *w1 = new TestPage(true);
+    w1->setN(3);
+
+    TestPage *w2 = new TestPage;
+    w2->setN(3);
+
+    sw->addWidget(w1);
+    sw->addWidget(w2);
+
+    QLineEdit *le11 = w1->findChild<QLineEdit*>(QLatin1String("lineEdit1"));
+    le11->setFocus();   // set focus to second widget in the page
+    sw->resize(200, 200);
+    sw->show();
+    qApp->setActiveWindow(sw);
+    QTest::qWaitForWindowShown(sw);
+    QTRY_COMPARE(QApplication::focusWidget(), le11);
+
+    sw->setCurrentIndex(1);
+    QLineEdit *le22 = w2->findChild<QLineEdit*>(QLatin1String("lineEdit2"));
+    le22->setFocus();
+    QTRY_COMPARE(QApplication::focusWidget(), le22);
+    // Going back should move focus back to le11
+    sw->setCurrentIndex(0);
+    QTRY_COMPARE(QApplication::focusWidget(), le11);
+
+}
+
 QTEST_MAIN(tst_QStackedWidget)
 #include "tst_qstackedwidget.moc"