+redef class UISwitch
+ # Register callbacks on this switch to be relayed to `sender`
+ private fun set_callback(sender: View)
+ import View.on_ios_event in "ObjC" `{
+
+ NitCallbackReference *ncr = [[NitCallbackReference alloc] init];
+ ncr.nit_view = sender;
+
+ // Pin the objects in both Objective-C and Nit GC
+ View_incr_ref(sender);
+ ncr = (__bridge NitCallbackReference*)CFBridgingRetain(ncr);
+
+ [self addTarget:ncr action:@selector(nitOnEvent:)
+ forControlEvents:UIControlEventValueChanged];
+ `}
+end
+