QQuickStackView: fix emptyChanged()

Don't emit emptyChanged() when popping down to 1 element.

Change-Id: Iff1e29567d1d6171cea0f158955325389c03800c
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

4 files changed, 58 insertions, 19 deletions

diff --git a/src/quicktemplates2/qquickstackview.cpp b/src/quicktemplates2/qquickstackview.cpp
index ee975056..3767d143 100644
--- a/src/quicktemplates2/qquickstackview.cpp
+++ b/src/quicktemplates2/qquickstackview.cpp
@@ -516,8 +516,9 @@ void QQuickStackView::push(QQmlV4Function *args)
     if (!d->elements.isEmpty())
         exit = d->elements.top();
 
+    int oldDepth = d->elements.count();
     if (d->pushElements(elements)) {
-        d->depthChange();
+        d->depthChange(d->elements.count(), oldDepth);
         QQuickStackElement *enter = d->elements.top();
         d->startTransition(QQuickStackTransition::pushEnter(operation, enter, this),
                            QQuickStackTransition::pushExit(operation, exit, this),
@@ -574,6 +575,7 @@ void QQuickStackView::pop(QQmlV4Function *args)
         return;
     }
 
+    int oldDepth = d->elements.count();
     QQuickStackElement *exit = d->elements.pop();
     QQuickStackElement *enter = d->elements.top();
 
@@ -612,7 +614,7 @@ void QQuickStackView::pop(QQmlV4Function *args)
             d->removing.insert(exit);
             previousItem = exit->item;
         }
-        d->depthChange();
+        d->depthChange(d->elements.count(), oldDepth);
         d->startTransition(QQuickStackTransition::popExit(operation, exit, this),
                            QQuickStackTransition::popEnter(operation, enter, this),
                            operation == Immediate);
@@ -752,14 +754,13 @@ void QQuickStackView::replace(QQmlV4Function *args)
         return;
     }
 
-    int depth = d->elements.count();
+    int oldDepth = d->elements.count();
     QQuickStackElement* exit = nullptr;
     if (!d->elements.isEmpty())
         exit = d->elements.pop();
 
     if (exit != target ? d->replaceElements(target, elements) : d->pushElements(elements)) {
-        if (depth != d->elements.count())
-            d->depthChange();
+        d->depthChange(d->elements.count(), oldDepth);
         if (exit) {
             exit->removal = true;
             d->removing.insert(exit);
@@ -820,10 +821,11 @@ void QQuickStackView::clear(Operation operation)
                            QQuickStackTransition::popEnter(operation, nullptr, this), false);
     }
 
+    int oldDepth = d->elements.count();
     d->setCurrentItem(nullptr);
     qDeleteAll(d->elements);
     d->elements.clear();
-    d->depthChange();
+    d->depthChange(0, oldDepth);
 }
 
 /*!
@@ -1020,6 +1022,7 @@ void QQuickStackView::componentComplete()
     QScopedValueRollback<QString> rollback(d->operation, QStringLiteral("initialItem"));
     QQuickStackElement *element = nullptr;
     QString error;
+    int oldDepth = d->elements.count();
     if (QObject *o = d->initialItem.value<QObject *>())
         element = QQuickStackElement::fromObject(o, this, &error);
     else if (d->initialItem.canConvert<QString>())
@@ -1027,7 +1030,7 @@ void QQuickStackView::componentComplete()
     if (!error.isEmpty()) {
         d->warn(error);
     } else if (d->pushElement(element)) {
-        d->depthChange();
+        d->depthChange(d->elements.count(), oldDepth);
         d->setCurrentItem(element);
         element->setStatus(QQuickStackView::Active);
     }
diff --git a/src/quicktemplates2/qquickstackview_p.cpp b/src/quicktemplates2/qquickstackview_p.cpp
index 69ad7848..f4405246 100644
--- a/src/quicktemplates2/qquickstackview_p.cpp
+++ b/src/quicktemplates2/qquickstackview_p.cpp
@@ -297,11 +297,14 @@ void QQuickStackViewPrivate::setBusy(bool b)
     emit q->busyChanged();
 }
 
-void QQuickStackViewPrivate::depthChange()
+void QQuickStackViewPrivate::depthChange(int newDepth, int oldDepth)
 {
     Q_Q(QQuickStackView);
+    if (newDepth == oldDepth)
+        return;
+
     emit q->depthChanged();
-    if (elements.count() <= 1)
+    if (newDepth == 0 || oldDepth == 0)
         emit q->emptyChanged();
 }
 
diff --git a/src/quicktemplates2/qquickstackview_p_p.h b/src/quicktemplates2/qquickstackview_p_p.h
index 871891aa..d86f35cd 100644
--- a/src/quicktemplates2/qquickstackview_p_p.h
+++ b/src/quicktemplates2/qquickstackview_p_p.h
@@ -92,7 +92,7 @@ public:
 
     void viewItemTransitionFinished(QQuickItemViewTransitionableItem *item) override;
     void setBusy(bool busy);
-    void depthChange();
+    void depthChange(int newDepth, int oldDepth);
 
     bool busy;
     QString operation;
diff --git a/tests/auto/controls/data/tst_stackview.qml b/tests/auto/controls/data/tst_stackview.qml
index 77929a0a..097180b8 100644
--- a/tests/auto/controls/data/tst_stackview.qml
+++ b/tests/auto/controls/data/tst_stackview.qml
@@ -221,42 +221,75 @@ TestCase {
     function test_depth() {
         var control = createTemporaryObject(stackView, testCase)
         verify(control)
+
+        var depthChanges = 0
+        var emptyChanges = 0
         var depthSpy = signalSpy.createObject(control, {target: control, signalName: "depthChanged"})
+        var emptySpy = signalSpy.createObject(control, {target: control, signalName: "emptyChanged"})
         verify(depthSpy.valid)
+        verify(emptySpy.valid)
         compare(control.depth, 0)
         compare(control.empty, true)
+
         control.push(item, StackView.Immediate)
         compare(control.depth, 1)
-        compare(depthSpy.count, 1)
+        compare(depthSpy.count, ++depthChanges)
         compare(control.empty, false)
+        compare(emptySpy.count, ++emptyChanges)
+
         control.clear()
         compare(control.depth, 0)
-        compare(depthSpy.count, 2)
+        compare(depthSpy.count, ++depthChanges)
         compare(control.empty, true)
+        compare(emptySpy.count, ++emptyChanges)
+
         control.push(component, StackView.Immediate)
         compare(control.depth, 1)
-        compare(depthSpy.count, 3)
+        compare(depthSpy.count, ++depthChanges)
         compare(control.empty, false)
+        compare(emptySpy.count, ++emptyChanges)
+
         control.push(component, StackView.Immediate)
         compare(control.depth, 2)
-        compare(depthSpy.count, 4)
+        compare(depthSpy.count, ++depthChanges)
         compare(control.empty, false)
-        control.pop(StackView.Immediate)
+        compare(emptySpy.count, emptyChanges)
+
+        control.replace(component, StackView.Immediate)
+        compare(control.depth, 2)
+        compare(depthSpy.count, depthChanges)
+        compare(control.empty, false)
+        compare(emptySpy.count, emptyChanges)
+
+        control.replace([component, component], StackView.Immediate)
+        compare(control.depth, 3)
+        compare(depthSpy.count, ++depthChanges)
+        compare(control.empty, false)
+        compare(emptySpy.count, emptyChanges)
+
+        control.pop(null, StackView.Immediate)
         compare(control.depth, 1)
-        compare(depthSpy.count, 5)
+        compare(depthSpy.count, ++depthChanges)
         compare(control.empty, false)
+        compare(emptySpy.count, emptyChanges)
+
         control.pop(StackView.Immediate) // ignored
         compare(control.depth, 1)
-        compare(depthSpy.count, 5)
+        compare(depthSpy.count, depthChanges)
         compare(control.empty, false)
+        compare(emptySpy.count, emptyChanges)
+
         control.clear()
         compare(control.depth, 0)
-        compare(depthSpy.count, 6)
+        compare(depthSpy.count, ++depthChanges)
         compare(control.empty, true)
+        compare(emptySpy.count, ++emptyChanges)
+
         control.clear()
         compare(control.depth, 0)
-        compare(depthSpy.count, 6)
+        compare(depthSpy.count, depthChanges)
         compare(control.empty, true)
+        compare(emptySpy.count, emptyChanges)
     }
 
     function test_size() {