The onShow method is called before making the view visible. For example, a list of objects displayed on the screen
by a view must be refreshed once a user returns back to the view after making changes in one of objects using an editor.
For this purpose, the refresh() method of the aps/Grid object helps as follows:
onShow: function() {
self.byId("srv_grid").refresh();
}
If the method returns a deferred promise by means of the dojo/Deferred module, UX1 will start the next
method, that must be onContext, only after the promise is resolved.