The protocol method controls the following window properties: WM_DELETE_WINDOW, WM_SAVE_YOURSELF, and WM_TAKE_FOCUS. The callback (if any) associated with each property will be invoked when the window manager recognizes the event associated with the property:
$toplevel->protocol ( [ property_name] [, callback ] );
The WM_DELETE_WINDOW property callback is invoked when the window has been deleted by the window manager. By default, there is a callback assigned by Perl/Tk that destroys the window. If you assign a new callback, your callback will be invoked instead of the default callback. If you need to save data associated with that window, do so in the callback, then invoke $toplevel->destroy() to mimic the correct behavior afterward.
The other two properties, WM_SAVE_YOURSELF and WM_TAKE_FOCUS, are used much less commonly. For instance, WM_TAKE_FOCUS is used in Unix systems but not in Win32. The presence of these properties is dependent on the window system you are running. If your application will be running on multiple systems, don't expect these properties to always be available. To find out if they are available, assign each one a callback that does a print, then run the application to see if the print is ever invoked.
If you leave out the callback when you use protocol, the current callback assigned to that property will be returned (or an empty string, if there isn't a current callback assigned). You can remove the callback by sending an empty string instead of the callback. If neither argument is specified, the method returns a list of all properties that have callbacks assigned to them.
作者: 唐勝 時間: 2018-04-17 10:11
my $mw = MainWindow->new( -title =>123);
$mw->protocol("WM_DELETE_WINDOW", \&OnQuit); ##設(shè)置退出執(zhí)行
sub OnQuit {
##執(zhí)行代碼
}