Old Listener interfaces

DUI D GTK+ binding Welcome What is DUI Screenshots sourceforge Page Contacts Downloads DUI Windows DUI Linux Developers Windows Tools dool Impact Tutorial Diffs to GTK Events Class Hierarchy Class Index Class List OpenGL To do roadmap To do Known Problems Links Site pages Links Acknowledgments	Warning: The event implementation will probably change to use delegates instead of listener interfaces see the discussion at started at Listeners interfaces or delegates? Description Any object can receive any event providing that it implements the correspondent listener and requests to receive it. all the listener interfaces declarations are on the event.Dispatcher module so we can have some thing like: How to create a listener First lets look at a listener interface declaration - All the listeners are defined on the module event.Dispatcher. (I'm trying to convince doxygen to document event.Dispatcher but it's not easy) // // Single mouse click on widget that support mouse click. // Examples are buttons and menu items. // public: interface ClickedListener { // defines only one method to implement // this will be called on the implementing class when the clicked event is generated void clickedPerformed(ObjectG objectG, char [] action); } We need a class that listens to mouse clicked actions class MyMenuListener : ClickedListener { void clickedPerformed(ObjectG obj, char [] action) { switch ( action ) { case "File.Exit": // do something here break; case "Help.About": // do something different here break; default: // oops : unknown action - do nothing maybe the user didn't notice break; } } } Instantiating the listener class MyMenuListener myMenuListener = new MyMenuListener; creating the a menu item (later it has to be added to a menu) MenuItem item = new MenuItem("Exit"); get this application dispatcher; Dispatcher dispatcher = Dispatcher.getDispather() request that myMenuListener receives event of type Clicked with action code "File.Exit" dispatcher.addClickedListener(myMenuListener,item,"File.Exit"); But DUI can simplify your life, if you already have a menu object then the last four steps can be replaced by: menu.append(new MenuItem(myMenuListener,"Exit","File.Exit")); Complete example from a real DUI class Here is the example of MainWindow. MainWindow is simply a Window that listens to window events. /* * This file is part of dui. * * dui is free software; you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 of the License, or * (at your option) any later version. * * dui is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with dui; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ module dui.MainWindow; private import def.Types; private import dui.DUI; private import dui.Widget; private import dui.Window; /** * A top Level window that will stop the main event cycle when it's closed. * Closing the last of the windows of class "MainWindow" will end the application. */ public: class MainWindow : Window { private import dool.String; private static int countTotalMainWindows = 0; debug(status) { int complete(){return 50;} char[] gtkName(){return SAME_NAME;} char[] description(){return "A top Level window that will stop the main event cycle when it's closed";} char[] author(){return "Antonio";} } public: /** * Creates a new MainWindow with a title */ this(char[] title) { this(new String(title)); } this(String title) { super(title); //printf("MainWindow.this \n"); countTotalMainWindows++; //printf("MainWindows.this count = %d\n", countTotalMainWindows); addOnDelete(&windowDelete); } public: /** * Executed when the user tries to close the window * @return true to refuse to close the window */ protected bit windowDelete(Window window, Event event) { --countTotalMainWindows; printf("MainWindows.windowDelete count = %d\n", countTotalMainWindows); if ( exit(0, countTotalMainWindows==0) || countTotalMainWindows==0 ) { DUI dui = DUI.dui(); dui.stop(); return false; } return false; } /** * Allows the application to close and decide if it can exit * @param code the code reason to exit * @param force if true the application must expect to be closed even against it's will * @return false to refuse to exit */ protected bit exit(int code, bit force) { return force; } } note that the MainWindow will stop the main GUI event cycle with dui.stop(); // effectively ends the GUI main event cycle closing all graphics elements making the following statement irrelevant return false; // returning true would keep the window open (if the main event cycle is still running)

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