Modale Fenster in Flash

Nachdem einige weitere Experimente und Untersuchungen, ich glaube ich habe ein ziemlich saubere Lösung. Das meiste davon basiert auf dem Beispiel in der offiziellen Dokumentation des FocusEvent event. Was folgt, ist eine vereinfachte version der implantation.

package
{

    import flash.events.Event;
    import flash.events.MouseEvent;
    import flash.events.FocusEvent;
    import flash.display.Sprite;
    import flash.display.Stage;

    public class Message
    {

        private static var overlay : Sprite;
        private static var dialog : Sprite;

        public static function show(stage : Stage, message : String)
        {

            //Close existing (if any).
            close();

            //Create dialog. They overlay sprite overlays the entire scene.
            overlay = createOverlay();
            dialog = createDialog(message);
            overlay.addChild(dialog);
            stage.addChild(overlay);

            //steal focus
            stage.focus = overlay;

            //Make sure the ugly yellow focus rectangle is hidden. Hiding it seems
            //to have one additional benefit. If we don’t do it, one can still 
            //change the focus using left and right arrow keys. The focus rectangle
            //actually moves to another element in the scene (first time I saw
            //something like this in Flash). If we hide it, the left and right arrow
            //keys actually don’t do anything. I did not find any documentation
            //related to this. So it may change in future. But if it changes,
            //possible workaround could be to simply catch the keyboard events
            //and prevent propagation. Such approach is also used in the official
            //AS3 documentation of the FocusEvent class:
            //
            //  http://livedocs.adobe.com/
            //      flash/9.0/ActionScriptLangRefV3/flash/events/FocusEvent.html
            //
            stage.stageFocusRect = false;

            //Even though the message overlays the entire stage, if you click
            //on it, it loses focus. My guess is that Flash does not find
            //anything obvious which can be focused (such as a textbox). The
            //following below forces Flash to keep the focus on the message.
            //This approach is also used in an example in the AS3 documentation,
            //of the of the FocusEvent class (see the link above) so it gives it
            //some credibility.
            overlay.addEventListener(MouseEvent.CLICK,
                function(event : MouseEvent) : void { stage.focus = overlay; });

            //In addition, when the entire Flash loses focus and it gets it later 
            //back, the container (browser) does not restore the previously focused
            //element. So we have to do it ourselves.
            stage.addEventListener(Event.ACTIVATE,
                function(event : Event) : void { stage.focus = overlay; });

            //And apparently, swallow all keyboard events.
            overlay.addEventListener(KeyboardEvent.KEY_DOWN,
                function(event : KeyboardEvent) : void { event.stopPropagation(); });

        }

        public static function close() : void
        {
            //snip ...
        }

        private static function createOverlay() : Sprite
        {
            //snip ...
        }

        private static function createDialog(message : String) : Sprite
        {
            //snip ...
        }

    }

}

InformationsquelleAutor Jan Zich