Package ch.bailu.gtk.gio

Interface SimpleAction.OnChangeState

Enclosing class:

SimpleAction

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public static interface SimpleAction.OnChangeState

Method Summary

Modifier and Type	Method	Description
void	onChangeState(Variant value)	Indicates that the action just received a request to change its state.

Method Details

onChangeState

void onChangeState(@Nullable
 Variant value)

Indicates that the action just received a request to change its
state.

@value will always be of the correct state type, i.e. the type of the
initial state passed to g_simple_action_new_stateful(). If an incorrect
type is given when requesting to change the state, this signal is not
emitted.

If no handler is connected to this signal then the default
behaviour is to call g_simple_action_set_state() to set the state
to the requested value. If you connect a signal handler then no
default action is taken. If the state should change then you must
call g_simple_action_set_state() from the handler.

An example of a 'change-state' handler:

<!-- language="C" -->
 static void
 change_volume_state (GSimpleAction *action,
                      GVariant      *value,
                      gpointer       user_data)
 {
   gint requested;
 
   requested = g_variant_get_int32 (value);
 
   // Volume only goes from 0 to 10
   if (0 <= requested && requested <= 10)
     g_simple_action_set_state (action, value);
 }
 

The handler need not set the state to the requested value.
It could set it to any value at all, or take some other action.

Parameters:

value - the requested value for the state