StackView: add attached activated() etc. signals

For initializing and cleaning up item-specific resources, these are
much more convenient than a StackView.onStatusChanged handler.

[ChangeLog][StackView] Added attached activated(), deactivated(),
activating(), and deactivating() signals that are convenient for
initializing and cleaning up item-specific resources.

Change-Id: If8df45b31a14cd2491db2c87eeb1c071af4e695f
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

3 files changed, 64 insertions, 2 deletions

diff --git a/src/quicktemplates2/qquickstackview.cpp b/src/quicktemplates2/qquickstackview.cpp
index 9c9cd5c2..d75dfc23 100644
--- a/src/quicktemplates2/qquickstackview.cpp
+++ b/src/quicktemplates2/qquickstackview.cpp
@@ -988,4 +988,42 @@ QQuickStackView::Status QQuickStackAttached::status() const
     return d->element ? d->element->status : QQuickStackView::Inactive;
 }
 
+/*!
+    \qmlattachedsignal QtQuick.Controls::StackView::activated()
+    \since QtQuick.Controls 2.1
+
+    This attached signal is emitted when the item it's attached to is activated in the stack.
+
+    \sa status
+*/
+
+/*!
+    \qmlattachedsignal QtQuick.Controls::StackView::deactivated()
+    \since QtQuick.Controls 2.1
+
+    This attached signal is emitted when the item it's attached to is deactivated in the stack.
+
+    \sa status
+*/
+
+/*!
+    \qmlattachedsignal QtQuick.Controls::StackView::activating()
+    \since QtQuick.Controls 2.1
+
+    This attached signal is emitted when the item it's attached to is in the process of being
+    activated in the stack.
+
+    \sa status
+*/
+
+/*!
+    \qmlattachedsignal QtQuick.Controls::StackView::deactivating()
+    \since QtQuick.Controls 2.1
+
+    This attached signal is emitted when the item it's attached to is in the process of being
+    dectivated in the stack.
+
+    \sa status
+*/
+
 QT_END_NAMESPACE
diff --git a/src/quicktemplates2/qquickstackview_p.cpp b/src/quicktemplates2/qquickstackview_p.cpp
index 809f7386..5a83f5e5 100644
--- a/src/quicktemplates2/qquickstackview_p.cpp
+++ b/src/quicktemplates2/qquickstackview_p.cpp
@@ -221,8 +221,28 @@ void QQuickStackElement::setStatus(QQuickStackView::Status value)
 
     status = value;
     QQuickStackAttached *attached = attachedStackObject(this);
-    if (attached)
-        emit attached->statusChanged();
+    if (!attached)
+        return;
+
+    switch (value) {
+    case QQuickStackView::Inactive:
+        emit attached->deactivated();
+        break;
+    case QQuickStackView::Deactivating:
+        emit attached->deactivating();
+        break;
+    case QQuickStackView::Activating:
+        emit attached->activating();
+        break;
+    case QQuickStackView::Active:
+        emit attached->activated();
+        break;
+    default:
+        Q_UNREACHABLE();
+        break;
+    }
+
+    emit attached->statusChanged();
 }
 
 void QQuickStackElement::transitionNextReposition(QQuickItemViewTransitioner *transitioner, QQuickItemViewTransitioner::TransitionType type, bool asTarget)
diff --git a/src/quicktemplates2/qquickstackview_p.h b/src/quicktemplates2/qquickstackview_p.h
index 5c119627..790ac4c5 100644
--- a/src/quicktemplates2/qquickstackview_p.h
+++ b/src/quicktemplates2/qquickstackview_p.h
@@ -175,6 +175,10 @@ Q_SIGNALS:
     void indexChanged();
     void viewChanged();
     void statusChanged();
+    Q_REVISION(1) void activated();
+    Q_REVISION(1) void activating();
+    Q_REVISION(1) void deactivated();
+    Q_REVISION(1) void deactivating();
 
 private:
     Q_DISABLE_COPY(QQuickStackAttached)