Let specifying the fallback style for custom styles

For example, you can call QQuickStyle::setStyle(":/mycontrols") and
QQuickStyle::setFallbackStyle("Material") to select a custom style so
that the missing files will fallback to the Material style.

Notice that the Material and Universal styles do not contain all files.
For example, the non-visual Control.qml, Container.qml are not duplicated.
For these, we must fallback to the Default style that is guaranteed to
contain them all.

[ChangeLog][Controls] Added support for specifying the fallback style for
custom styles via :/qtquickcontrols2.conf, QT_QUICK_CONTROLS_FALLBACK_STYLE
or QQuickStyle::setFallbackStyle().

Change-Id: I00be1c8c6aaca875ef851c90d018e9b5e2f501b7
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

1 files changed, 4 insertions, 1 deletions

diff --git a/src/quickcontrols2/qquickstyleselector_p_p.h b/src/quickcontrols2/qquickstyleselector_p_p.h
index cc3f0a58..4ff28d5d 100644
--- a/src/quickcontrols2/qquickstyleselector_p_p.h
+++ b/src/quickcontrols2/qquickstyleselector_p_p.h
@@ -54,9 +54,12 @@ class QQuickStyleSelectorPrivate
 {
 public:
     QString select(const QString &filePath) const;
+    QString trySelect(const QString &filePath, const QString &fallback = QString()) const;
 
     QUrl baseUrl;
-    QString style;
+    QString basePath;
+    QString styleName;
+    QString stylePath;
 };
 
 QT_END_NAMESPACE