public static interface Widget.UnmapEvent

The signal emitted when a Window becomes invisible. This happens in a variety of scenarios, notably when the Window is minimized, when you change workspaces, and as a Window is being destroyed.

In combination with Widget.VisibilityNotifyEvent, this can be used to detect whether a Window is actually currently presented to the top of the stack and visible to the user:

 private boolean up = false;
 ...
 final Window w;
 final Button b;
 ...
 w.connect(new Widget.VisibilityNotifyEvent() {
     public boolean onVisibilityNotifyEvent(Widget source, EventVisibility event) {
         if (event.getState() == VisibilityState.UNOBSCURED) {
             up = true;
         } else {
             up = false;
         }
         return false;
     }
 });
 
 w.connect(new Widget.UnmapEvent() {
     public boolean onUnmapEvent(Widget source, Event event) {
         up = false;
         return false;
     }
 });
 

thus allowing you to do something like:

 b.connect(new Button.Clicked() {
     public void onClicked(Button source) {
         if (up) {
             w.hide();
             up = false;
         } else {
             w.present();
             up = true;
         }
     }
 });
 

to intelligently toggle the visibility of the Window.

Note that you don't need Widget.MapEvent here because the the Widget.VisibilityNotifyEvent will be tripped if you come back to the workspace the Window is already on.