Show modal window while doing something

DialogFieldManager manager = new DialogFieldManager();

manager.addCustomField(new LabelField("Please Wait..."));

final Screen popup = new PopupScreen(manager);

UiApplication.getUiApplication().invokeLater(new Runnable() {

public void run() {

UiApplication.getUiApplication().pushScreen(popup);

}

});

//Do something long and important

UiApplication.getUiApplication().invokeLater(new Runnable() {

public void run() {

UiApplication.getUiApplication().popScreen(UiApplication.getUiApplication().getActiveScreen());

}

});