parameter will always be of the expected type, i.e. the parameter type
specified when the action was created. If an incorrect type is given when
activating the action, this signal is not emitted.
Since GLib 2.40, if no handler is connected to this signal then the
default behaviour for boolean-stated actions with a NULL parameter
type is to toggle them via the change-state signal.
For stateful actions where the state type is equal to the parameter
type, the default is to forward them directly to
change-state. This should allow almost all users
of gio.SimpleAction to connect only one handler or the other.
Indicates that the action was just activated.
parameter will always be of the expected type, i.e. the parameter type specified when the action was created. If an incorrect type is given when activating the action, this signal is not emitted.
Since GLib 2.40, if no handler is connected to this signal then the default behaviour for boolean-stated actions with a NULL parameter type is to toggle them via the change-state signal. For stateful actions where the state type is equal to the parameter type, the default is to forward them directly to change-state. This should allow almost all users of gio.SimpleAction to connect only one handler or the other.