QtでJson

main.cc

#include <QCoreApplication>
#include <QJsonDocument>
#include <QJsonObject>
#include <QDebug>

int main(int argc, char *argv[]) {
  QCoreApplication a(argc, argv);

  auto json = QJsonDocument::fromJson(QByteArray(R"(
    {
      "relationship": {
        "target": {
          "id_str": "12148",
          "id": 12148,
          "screen_name": "ernie",
          "following": false,
          "followed_by": false
        },
        "source": {
          "can_dm": false,
          "blocking": null,
          "muting": null,
          "id_str": "8649302",
          "all_replies": null,
          "want_retweets": null,
          "id": 8649302,
          "marked_spam": null,
          "screen_name": "bert",
          "following": false,
          "followed_by": false,
          "notifications_enabled": null
        }
      }
    }
  )"));

  // "relationship" => "source" => "screen_name" の文字列が取りたい

  // 理想
  // qDebug() << json["relationship"]["source"]["screen_name"].toString();

  // 現実
  qDebug() << json.object().value("relationship").toObject().value("source").toObject().value("screen_name").toString();

  return a.exec();
}