@Override
public void onClick(View view) {
    if (_oaLeft.isRunning() || _oaRight.isRunning() || _crossfadeRunning) return;

    SharedPreferences.Editor editor = _sp.edit();
    boolean pref = _sp.getBoolean(_prefName, false);
    if (pref) {
        _oaLeft.start();
        _crossfadeViews(background_oval_on, background_oval_off, 110);
    }
    else {
        _oaRight.start();
        _crossfadeViews(background_oval_off, background_oval_on, 400);
    }

    editor.putBoolean(_prefName, !pref);
    editor.apply();
}