ruby-****@sourc*****
ruby-****@sourc*****
2009年 2月 23日 (月) 10:13:33 JST
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REMOTE_ADDR = 74.15.84.244
REMOTE_HOST =
URL = http://ruby-gnome2.sourceforge.jp/hiki.cgi?tut-gtk2-mnstbs-statb
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@@ -173,6 +173,6 @@
When implementing status bar hints, you first need to figure out what signals are necessary. We want to be able to add a message to the status bar when the mouse cursor moves over the menu item, and remove it when the cursor leaves. For this scenario the ((*enter-notify-event*)) and ((*leave-notify-event*)) seem like a reasonable choice.
-When working with signals we usually have to be concerned about the callback block parameters that are passed along when a callback is invoked. Namely if we use a single callback method for two different signals, like our ((*statusbar_hint*)) method, we should rely on these parameters to identify which event occurred, and most likely which device (in our case menu item) emitted it. Both ((*'enter-notify-event'*)) and ((*'leave-notify-event'*)) pass the signal emitting widget, and the Gtk::EventCrossing object which is a descendant of Gtk::Event object that will provide us with the needed info, namely whether we are dealing with an entering or leaving cursor. For that we use the Gtk::Event#event_type accessor method retrieving either Gdk::Event::ENTER_NOTIFY or Gdk::Event::LEAVE_NOTIFY event id value.
+When working with signals we usually have to be concerned about the callback block parameters that are passed along when a callback is invoked. Namely, if we use a single callback method for two different signals, like in our ((*statusbar_hint*)) method, we should rely on these parameters to identify which event occurred, and most likely which device (in our case menu item) emitted it. Both ((*'enter-notify-event'*)) and ((*'leave-notify-event'*)) pass the signal emitting widget, and the Gtk::EventCrossing object which is a descendant of Gtk::Event object that will provide us with the needed info, namely whether we are dealing with an entering or leaving cursor. For that we use the Gtk::Event#event_type accessor method retrieving either Gdk::Event::ENTER_NOTIFY or Gdk::Event::LEAVE_NOTIFY event id value.
To identify the menu item, we had to do some preparation work at the time when menu items were created. We assigned them the name by calling Gtk::Widget#name=. We use this name in two places: (1) to store status messages in a hash where this widget's (menu item's) name is the key, and (2) in callback method where we use this menu item's name as a key to retrieve the appropriate message.