snackbar.addCallback(new Snackbar.Callback() {

    @Override
    public void onDismissed(Snackbar snackbar, int event) {
        if (event == Snackbar.Callback.DISMISS_EVENT_TIMEOUT) {
            // Snackbar closed on its own
        }
    }

    @Override
    public void onShown(Snackbar snackbar) {
        ...
    }
});