logfilepositionsource.cpp Example File

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  #include <QtCore>

  #include "logfilepositionsource.h"

  LogFilePositionSource::LogFilePositionSource(QObject *parent)
      : QGeoPositionInfoSource(parent),
        logFile(new QFile(this)),
        timer(new QTimer(this))
  {
      connect(timer, SIGNAL(timeout()), this, SLOT(readNextPosition()));

      logFile->setFileName(":/simplelog.txt");
      if (!logFile->open(QIODevice::ReadOnly))
          qWarning() << "Error: cannot open source file" << logFile->fileName();
  }

  QGeoPositionInfo LogFilePositionSource::lastKnownPosition(bool /*fromSatellitePositioningMethodsOnly*/) const
  {
      return lastPosition;
  }

  LogFilePositionSource::PositioningMethods LogFilePositionSource::supportedPositioningMethods() const
  {
      return AllPositioningMethods;
  }

  int LogFilePositionSource::minimumUpdateInterval() const
  {
      return 500;
  }

  void LogFilePositionSource::startUpdates()
  {
      int interval = updateInterval();
      if (interval < minimumUpdateInterval())
          interval = minimumUpdateInterval();

      timer->start(interval);
  }

  void LogFilePositionSource::stopUpdates()
  {
      timer->stop();
  }

  void LogFilePositionSource::requestUpdate(int /*timeout*/)
  {
      // For simplicity, ignore timeout - assume that if data is not available
      // now, no data will be added to the file later
      if (logFile->canReadLine())
          readNextPosition();
      else
          emit updateTimeout();
  }

  void LogFilePositionSource::readNextPosition()
  {
      QByteArray line = logFile->readLine().trimmed();
      if (!line.isEmpty()) {
          QList<QByteArray> data = line.split(' ');
          double latitude;
          double longitude;
          bool hasLatitude = false;
          bool hasLongitude = false;
          QDateTime timestamp = QDateTime::fromString(QString(data.value(0)), Qt::ISODate);
          latitude = data.value(1).toDouble(&hasLatitude);
          longitude = data.value(2).toDouble(&hasLongitude);

          if (hasLatitude && hasLongitude && timestamp.isValid()) {
              QGeoCoordinate coordinate(latitude, longitude);
              QGeoPositionInfo info(coordinate, timestamp);
              if (info.isValid()) {
                  lastPosition = info;
                  emit positionUpdated(info);
              }
          }
      }
  }

  QGeoPositionInfoSource::Error LogFilePositionSource::error() const
  {
      return QGeoPositionInfoSource::NoError;
  }