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(QCoreApplication::applicationDirPath()
             + QDir::separator() + "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::UnknownSourceError;
 }