Hi, 2010/1/6 Arc Riley <[email protected]>: > Why does a class's init method get called before its construct method? First, I'm not sure about genie's init vs construct, but if I understand correctly, your short answer is : use Object(property: value) instead of property = value (and maybe mark your property as construct) > > This seems very counter-intuitive to me given the limitations on the > construct method; I've seen a difference recently, it may be because of the recent change of construct properties.
GObject construction needs to be well explained (I'm not sure this is 100% accurate, but it gives a good idea, any corrections are welcome) : There is : * the creation method (I'm not sure if this is the init or construct block in genie) takes parameters and sets properties, they can cain up to any base class creation method provided that it isn't [CCode (has_construct_function=true)] (in practice this means either a class written in vala, or GLib.Object). * The constructor (construct block in vala) is called *from* the creation method, and -here is your problem- you need to set the properties you need before it's called. The only properties that are guarenteed to be set on construction are construct properties, and the preferred (only?) way to set them is by chaining up to GLib.Object. > > A *construct* block is used to define a creation method which requires > parameters at construction time when being instantiated via the new so it's not the same as vala. > operator. Creation methods are limited to setting the properties of the > class and may perform no other task (an init block should be used to perform > any other type of initialization). A class can have many creation methods > with either different names or different parameters. A default creation > method without any parameters is always available if no explicit creation > method is defined. > > Since init runs first, none of the initialization code has access to > parameters passed to it by the new function. Say, for example, an argument > passed is a parent container for the new instance to add itself to - all the > construct method is allowed to do (if I read this correctly) is set > self._parent which only happens after init has run. As explained above, the init block runs as soon as you chain up, so you need to chain up to GLib.Object to set construct properties rather using assignment. HTH, Abderrahim P.S. we need to start a wiki page about gobject construction like the one on memory management. _______________________________________________ Vala-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/vala-list
