Hooks

Hooks allow you to execute code at different points throughout a widget's lifecycle, or when an action on one of its fields occurs.

Most hooks are defined only for Widgets, some are defined for both and property is only available as a hook for fields.

The available hooks are:

Hook Type	For renderables	For viewables	Name	Description
W	Yes	Yes	BeforeBuild	Executed only once before the `WidgetState` is created.
WF	Yes	Yes	Build	Executed only once after `WidgetState` is instantiated from `Widget`. Default values have not yet been applied and will overwrite any values set within this hook.
W	Yes	Yes	AfterBuild	Executed only once after the `WidgetState` was created. Is executed after all default values have been applied.
W	Yes	No	ConnectEvents	Only relevant for renderables. Executed every time a callback is supposed to be attached to the underlying GTK widget. It defines how to do so.
W	Yes	No	DisconnectEvents	Only relevant for renderables. Executed every time a callback is supposed to be removed from the underlying GTK widget. It defines how to do so.
WF	Yes	Yes	Update	Executed every time `WidgetState` is updated by `Widget`.
F	Yes	Yes	Property	Executed every time the hook-field changed its value during the update or build phases.
F	Yes	No	Read	Used in `Dialog`. Executes every time the state of the underlying GTK-Widget changes.

W: Can act as hook for Widgets F: Can act as hook for fields

All hooks have implicit access to a variable called state, which contains the WidgetState-instance of your particular widget.

With the exception of read, all hooks also have implicit access to a variable called widget, which is the Widget instance.

Generally the build, property and update hooks are likely to have the highest utility for you. Consult their individual sections for more information.