Qt 5.11 | Qt Core | JSON Save Game Example | game.cpp Example File

Qt 5.11.3 Reference Documentation

# game.cpp Example File

serialization/savegame/game.cpp

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      #include "game.h"

      #include <QFile>
      #include <QJsonArray>
      #include <QJsonDocument>
      #include <QRandomGenerator>
      #include <QTextStream>

      Character Game::player() const
      {
          return mPlayer;
      }

      QVector<Level> Game::levels() const
      {
          return mLevels;
      }

      void Game::newGame()
      {
          mPlayer = Character();
          mPlayer.setName(QStringLiteral("Hero"));
          mPlayer.setClassType(Character::Archer);
          mPlayer.setLevel(QRandomGenerator::global()->bounded(15, 21));

          mLevels.clear();
          mLevels.reserve(2);

          Level village(QStringLiteral("Village"));
          QVector<Character> villageNpcs;
          villageNpcs.reserve(2);
          villageNpcs.append(Character(QStringLiteral("Barry the Blacksmith"),
                                       QRandomGenerator::global()->bounded(8, 11),
                                       Character::Warrior));
          villageNpcs.append(Character(QStringLiteral("Terry the Trader"),
                                       QRandomGenerator::global()->bounded(6, 8),
                                       Character::Warrior));
          village.setNpcs(villageNpcs);
          mLevels.append(village);

          Level dungeon(QStringLiteral("Dungeon"));
          QVector<Character> dungeonNpcs;
          dungeonNpcs.reserve(3);
          dungeonNpcs.append(Character(QStringLiteral("Eric the Evil"),
                                       QRandomGenerator::global()->bounded(18, 26),
                                       Character::Mage));
          dungeonNpcs.append(Character(QStringLiteral("Eric's Left Minion"),
                                       QRandomGenerator::global()->bounded(5, 7),
                                       Character::Warrior));
          dungeonNpcs.append(Character(QStringLiteral("Eric's Right Minion"),
                                       QRandomGenerator::global()->bounded(4, 9),
                                       Character::Warrior));
          dungeon.setNpcs(dungeonNpcs);
          mLevels.append(dungeon);
      }

      bool Game::loadGame(Game::SaveFormat saveFormat)
      {
          QFile loadFile(saveFormat == Json
              ? QStringLiteral("save.json")
              : QStringLiteral("save.dat"));

          if (!loadFile.open(QIODevice::ReadOnly)) {
              qWarning("Couldn't open save file.");
              return false;
          }

          QByteArray saveData = loadFile.readAll();

          QJsonDocument loadDoc(saveFormat == Json
              ? QJsonDocument::fromJson(saveData)
              : QJsonDocument::fromBinaryData(saveData));

          read(loadDoc.object());

          QTextStream(stdout) << "Loaded save for "
                              << loadDoc["player"]["name"].toString()
                              << " using "
                              << (saveFormat != Json ? "binary " : "") << "JSON...\n";
          return true;
      }

      bool Game::saveGame(Game::SaveFormat saveFormat) const
      {
          QFile saveFile(saveFormat == Json
              ? QStringLiteral("save.json")
              : QStringLiteral("save.dat"));

          if (!saveFile.open(QIODevice::WriteOnly)) {
              qWarning("Couldn't open save file.");
              return false;
          }

          QJsonObject gameObject;
          write(gameObject);
          QJsonDocument saveDoc(gameObject);
          saveFile.write(saveFormat == Json
              ? saveDoc.toJson()
              : saveDoc.toBinaryData());

          return true;
      }

      void Game::read(const QJsonObject &json)
      {
          if (json.contains("player") && json["player"].isObject())
              mPlayer.read(json["player"].toObject());

          if (json.contains("levels") && json["levels"].isArray()) {
              QJsonArray levelArray = json["levels"].toArray();
              mLevels.clear();
              mLevels.reserve(levelArray.size());
              for (int levelIndex = 0; levelIndex < levelArray.size(); ++levelIndex) {
                  QJsonObject levelObject = levelArray[levelIndex].toObject();
                  Level level;
                  level.read(levelObject);
                  mLevels.append(level);
              }
          }
      }

      void Game::write(QJsonObject &json) const
      {
          QJsonObject playerObject;
          mPlayer.write(playerObject);
          json["player"] = playerObject;

          QJsonArray levelArray;
          foreach (const Level level, mLevels) {
              QJsonObject levelObject;
              level.write(levelObject);
              levelArray.append(levelObject);
          }
          json["levels"] = levelArray;
      }

      void Game::print(int indentation) const
      {
          const QString indent(indentation * 2, ' ');
          QTextStream(stdout) << indent << "Player\n";
          mPlayer.print(indentation + 1);

          QTextStream(stdout) << indent << "Levels\n";
          for (Level level : mLevels)
              level.print(indentation + 1);
      }