+ GVariant *const value = _getter ? _getter() : NULL;
+
+ if (value) {
+ _spin_box->setValue(g_variant_get_double(value));
+ g_variant_unref(value);
+ }
+
+ if (auto_commit)
+ connect(_spin_box, SIGNAL(valueChanged(double)),
+ this, SLOT(on_value_changed(double)));
+