DefaultUIService: handle status events

Instead of having each StatusBar implementation listen for events with
essentially the same onEvent code each time, the DefaultUIService will
listen for status events and then pass the message on to each active
UI's StatusBar.

Author: hinerm

src/main/java/org/scijava/ui/DefaultUIService.java

@@ -434,6 +434,27 @@ protected void onEvent(@SuppressWarnings("unused") final AppQuitEvent event) {
 		}
 	}
 
+	@EventHandler
+	protected void onEvent(final StatusEvent event) {
+		if (event.isWarning()) {
+			// report warning messages to the user in a dialog box
+			final String message = event.getStatusMessage();
+			if (message != null && !message.isEmpty()) {
+				showDialog(message, MessageType.WARNING_MESSAGE);
+			}
+		}
+		else {
+			// tell each UI to report status updates in the status bar
+			final int val = event.getProgressValue();
+			final int max = event.getProgressMaximum();
+			final String message = getStatusMessage(event);
+			for (UserInterface ui : getAvailableUIs()) {
+				ui.getStatusBar().setStatus(message);
+				ui.getStatusBar().setProgress(val, max);
+			}
+		}
+	}
+
 	// -- Helper methods --
 
 	private List<DisplayViewer<?>> displayViewers() {