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  1. Qt
  2. QTBUG-62601

Add QQmlApplicationEngine::clear() to delete root objects after clearComponentCache() is called

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      http://doc.qt.io/qt-5/qqmlengine.html#clearComponentCache can be used to clear any loaded components, but it doesn't take care of deleting the instances of those components. If a user wants to reload the QML in their application after calling clearComponentCache(), it is not currently clear how they would do it. Apparently, deleting the root objects is enough for this, as QQmlApplicationEngine listens to the destroyed signal:

      void QQmlApplicationEnginePrivate::finishLoad(QQmlComponent *c)
{
    Q_Q(QQmlApplicationEngine);
    switch (c->status()) {
    case QQmlComponent::Error:
        qWarning() << "QQmlApplicationEngine failed to load component";
        qWarning() << qPrintable(c->errorString());
        q->objectCreated(0, c->url());
        break;
    case QQmlComponent::Ready: {
        auto newObj = c->create();
        objects << newObj;
        QObject::connect(newObj, &QObject::destroyed, q, [&](QObject *obj) { objects.removeAll(obj); });
        q->objectCreated(objects.constLast(), c->url());
        }
        break;
    case QQmlComponent::Loading:
    case QQmlComponent::Null:
        return; //These cases just wait for the next status update
    }

      A QQmlApplicationEngine::clear() function would make it obvious how to achieve this.

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            qt.team.quick.subscriptions Qt Quick and Widgets Team
            mitch_curtis Mitch Curtis
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              Created:
              Updated:

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