Writing a GTK+ custom widget with Vala is easy. First all create an XML definition with a top level container widget and a set of child ones. You can use Glade to do so. This is not a tutorial for Glade, so let start at with an already designed template UI file.
For this Glade UI file to be useful in this tutorial pay attention on:
- The top level widget’s type must be the same of the one your Vala class is derived from.
- The top level widget in your UI file must be declared as a template and should have the same ID as your class, this is the C name, a class called Cust.DateChooser, should be called CustDateChooser in order to allow Vala’s compiler to find its UI definition.
- The child widgets, to be controlled by your class should have an ID.
Take in account all these for following delivers.