@Override
    public void execute() {
        if (!canExecute()) {
            return;
        }
        final AsyncTaskWithProgress<Void, Void> task = new ActionAsyncTask(context, null, progressMessage, true);
        task.execute();
    }
Message to be shown as toast when the command finished. Can be {@code null}, if the operation does not support
undo.
main/src/main/java/cgeo/geocaching/command/AbstractCommand.java