public class PleaseWaitPopup extends PopupScreen {
    private PleaseWaitPopup(String msg) {
        super(new VerticalFieldManager());
        add(new LabelField(msg));
    }

    /**
     * This method shows the user a 'please wait' dialog while waiting for a monitor to be unlocked.
     * Execution of the current thread is blocked until the monitor is unlocked.
     * @param msg Message to be shown to the user
     * @param monitor
     */
    public static void waitForUnlock(String msg, final Object monitor) {
        final PleaseWaitPopup popup = new PleaseWaitPopup(msg);
        final UiApplication app = UiApplication.getUiApplication();

        app.invokeLater(new Runnable() {
            public void run() {
                app.pushModalScreen(popup);
            }
        });

        synchronized(monitor) {}

        app.invokeLater(new Runnable() {
            public void run() {
                popup.close();
            }
        });
    }

}