mobile-widgets: add pure interface for passing values to QML

Add a header file that contains a duplicate of the enums,
that are needed in QML in one class.
the unit enums are added imidiatly, since they are needed
or will be neede shortly in Settings and DivePlannerSettings

This class will also contain Q_PROPERTY and signal/slot for
variables used in QML. This is done to allow e.g.

deco_mode qPrefUnits::planner_deco_mode()
void qPrefUnits::set_planner_deco_mode(deco_mode)
as strongly typed in C++
and
DECO_MODE planner_deco_mode()
void set_planner_deco_mode(DECO_MODE)
as strongly typed in QML
Remark: wrong assignments gives errors in QML

The advantage over using strings or the value directly is that
QML detects typos and flags them as errors/warnings.

It is important to note that the class may only contain
a) a function call to the implementation
b) a reference to a global variable e.g. prefs.

Added note to the original definitions of the enums that they
have been duplicated.

Signed-off-by: jan Iversen <jan@casacondor.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/mobile-widgets/qmlinterface.cpp b/mobile-widgets/qmlinterface.cpp
new file mode 100644
index 000000000..78aba6a5c
--- /dev/null
+++ b/mobile-widgets/qmlinterface.cpp
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "qmlinterface.h"
+
+#include <QQmlEngine>
+
+QMLInterface *QMLInterface::instance()
+{
+	static QMLInterface *self = new QMLInterface;
+	return self;
+}
+
+void QMLInterface::setup(QQmlContext *ct)
+{
+	// Register interface class
+	ct->setContextProperty("Backend", QMLInterface::instance());
+
+	// Make enums available as types
+	qmlRegisterUncreatableType<QMLInterface>("org.subsurfacedivelog.mobile",1,0,"Enums","Enum is not a type");
+
+	// relink signals to QML
+}