QQuickView/QQuickWidget: Report an error if rootObject ends up null.

This can happen when trying to use a non-QQuickItem item as the root item in a
QQuickView, for instance, a Window or ApplicationWindow item.

This generates a warning (correctly), but does not set an error state on the
view, so automated tooling and the like does not know that the scene was not
successfully loaded.

Change-Id: I1dc4191ef07187e9b1929995aedb01c155b0957c
Reviewed-by: Alan Alpert <aalpert@blackberry.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/quickwidgets/qquickwidget.cpp b/src/quickwidgets/qquickwidget.cpp
index 3bdf0bfc0a..f5b2122b60 100644
--- a/src/quickwidgets/qquickwidget.cpp
+++ b/src/quickwidgets/qquickwidget.cpp
@@ -530,6 +530,9 @@ QQuickWidget::Status QQuickWidget::status() const
     if (!d->component)
         return QQuickWidget::Null;
 
+    if (d->component->status() == QQmlComponent::Ready && !d->root)
+        return QQuickWidget::Error;
+
     return QQuickWidget::Status(d->component->status());
 }
 
@@ -551,6 +554,10 @@ QList<QQmlError> QQuickWidget::errors() const
         QQmlError error;
         error.setDescription(QLatin1String("QQuickWidget: invalid qml engine."));
         errs << error;
+    } else if (d->component->status() == QQmlComponent::Ready && !d->root) {
+        QQmlError error;
+        error.setDescription(QLatin1String("QQuickWidget: invalid root object."));
+        errs << error;
     }
 
     return errs;