QJsonDocument doc_a = QJsonDocument::fromJson(answer);
    QJsonObject obj_a = doc_a.object();
    QJsonArray arr = obj_a["response"].toArray();
    foreach (const QJsonValue & value, arr)
    {
        QJsonObject jsObj = value.toObject();
        QString urlTr;
        urlTr << jsObj ["url"].toString;
        propertyNames << jsObj["artist"].toString() << "--"  << jsObj["title"].toString();
        tmp = jsObj["artist"].toString() + "--"  + jsObj["title"].toString();
        lists[tmp] = jsObj["aid"].toString();
    }
 
    for(List::iterator itr = lists.begin(); itr != lists.end(); itr++)
        ui->comboBox->addItem(itr.key());