Qt 5.7Qt PositioningWeather Info (C++/QML)appmodel.cpp Example File
Qt 5.7.1 Reference Documentation

appmodel.cpp Example File

weatherinfo/appmodel.cpp 

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  #include "appmodel.h"

  #include <qgeopositioninfosource.h>
  #include <qgeosatelliteinfosource.h>
  #include <qnmeapositioninfosource.h>
  #include <qgeopositioninfo.h>
  #include <qnetworkconfigmanager.h>
  #include <qnetworksession.h>

  #include <QSignalMapper>
  #include <QJsonDocument>
  #include <QJsonObject>
  #include <QJsonArray>
  #include <QStringList>
  #include <QTimer>
  #include <QUrlQuery>
  #include <QElapsedTimer>
  #include <QLoggingCategory>

  /*
   *This application uses http://openweathermap.org/api
   **/

  #define ZERO_KELVIN 273.15

  Q_LOGGING_CATEGORY(requestsLog,"wapp.requests")

  WeatherData::WeatherData(QObject *parent) :
          QObject(parent)
  {
  }

  WeatherData::WeatherData(const WeatherData &other) :
          QObject(0),
          m_dayOfWeek(other.m_dayOfWeek),
          m_weather(other.m_weather),
          m_weatherDescription(other.m_weatherDescription),
          m_temperature(other.m_temperature)
  {
  }

  QString WeatherData::dayOfWeek() const
  {
      return m_dayOfWeek;
  }

  /*!
   * The icon value is based on OpenWeatherMap.org icon set. For details
   * see http://bugs.openweathermap.org/projects/api/wiki/Weather_Condition_Codes
   *
   * e.g. 01d ->sunny day
   *
   * The icon string will be translated to
   * http://openweathermap.org/img/w/01d.png
   */
  QString WeatherData::weatherIcon() const
  {
      return m_weather;
  }

  QString WeatherData::weatherDescription() const
  {
      return m_weatherDescription;
  }

  QString WeatherData::temperature() const
  {
      return m_temperature;
  }

  void WeatherData::setDayOfWeek(const QString &value)
  {
      m_dayOfWeek = value;
      emit dataChanged();
  }

  void WeatherData::setWeatherIcon(const QString &value)
  {
      m_weather = value;
      emit dataChanged();
  }

  void WeatherData::setWeatherDescription(const QString &value)
  {
      m_weatherDescription = value;
      emit dataChanged();
  }

  void WeatherData::setTemperature(const QString &value)
  {
      m_temperature = value;
      emit dataChanged();
  }

  class AppModelPrivate
  {
  public:
      static const int baseMsBeforeNewRequest = 5 * 1000; // 5 s, increased after each missing answer up to 10x
      QGeoPositionInfoSource *src;
      QGeoCoordinate coord;
      QString longitude, latitude;
      QString city;
      QNetworkAccessManager *nam;
      QNetworkSession *ns;
      WeatherData now;
      QList<WeatherData*> forecast;
      QQmlListProperty<WeatherData> *fcProp;
      QSignalMapper *geoReplyMapper;
      QSignalMapper *weatherReplyMapper, *forecastReplyMapper;
      bool ready;
      bool useGps;
      QElapsedTimer throttle;
      int nErrors;
      int minMsBeforeNewRequest;
      QTimer delayedCityRequestTimer;
      QTimer requestNewWeatherTimer;
      QString app_ident;

      AppModelPrivate() :
              src(NULL),
              nam(NULL),
              ns(NULL),
              fcProp(NULL),
              ready(false),
              useGps(true),
              nErrors(0),
              minMsBeforeNewRequest(baseMsBeforeNewRequest)
      {
          delayedCityRequestTimer.setSingleShot(true);
          delayedCityRequestTimer.setInterval(1000); // 1 s
          requestNewWeatherTimer.setSingleShot(false);
          requestNewWeatherTimer.setInterval(20*60*1000); // 20 min
          throttle.invalidate();
          app_ident = QStringLiteral("36496bad1955bf3365448965a42b9eac");
      }
  };

  static void forecastAppend(QQmlListProperty<WeatherData> *prop, WeatherData *val)
  {
      Q_UNUSED(val);
      Q_UNUSED(prop);
  }

  static WeatherData *forecastAt(QQmlListProperty<WeatherData> *prop, int index)
  {
      AppModelPrivate *d = static_cast<AppModelPrivate*>(prop->data);
      return d->forecast.at(index);
  }

  static int forecastCount(QQmlListProperty<WeatherData> *prop)
  {
      AppModelPrivate *d = static_cast<AppModelPrivate*>(prop->data);
      return d->forecast.size();
  }

  static void forecastClear(QQmlListProperty<WeatherData> *prop)
  {
      static_cast<AppModelPrivate*>(prop->data)->forecast.clear();
  }

  AppModel::AppModel(QObject *parent) :
          QObject(parent),
          d(new AppModelPrivate)
  {
      d->fcProp = new QQmlListProperty<WeatherData>(this, d,
                                                            forecastAppend,
                                                            forecastCount,
                                                            forecastAt,
                                                            forecastClear);

      d->geoReplyMapper = new QSignalMapper(this);
      d->weatherReplyMapper = new QSignalMapper(this);
      d->forecastReplyMapper = new QSignalMapper(this);

      connect(d->geoReplyMapper, SIGNAL(mapped(QObject*)),
              this, SLOT(handleGeoNetworkData(QObject*)));
      connect(d->weatherReplyMapper, SIGNAL(mapped(QObject*)),
              this, SLOT(handleWeatherNetworkData(QObject*)));
      connect(d->forecastReplyMapper, SIGNAL(mapped(QObject*)),
              this, SLOT(handleForecastNetworkData(QObject*)));
      connect(&d->delayedCityRequestTimer, SIGNAL(timeout()),
              this, SLOT(queryCity()));
      connect(&d->requestNewWeatherTimer, SIGNAL(timeout()),
              this, SLOT(refreshWeather()));
      d->requestNewWeatherTimer.start();

      // make sure we have an active network session
      d->nam = new QNetworkAccessManager(this);

      QNetworkConfigurationManager ncm;
      d->ns = new QNetworkSession(ncm.defaultConfiguration(), this);
      connect(d->ns, SIGNAL(opened()), this, SLOT(networkSessionOpened()));
      // the session may be already open. if it is, run the slot directly
      if (d->ns->isOpen())
          this->networkSessionOpened();
      // tell the system we want network
      d->ns->open();
  }

  AppModel::~AppModel()
  {
      d->ns->close();
      if (d->src)
          d->src->stopUpdates();
      delete d;
  }

  void AppModel::networkSessionOpened()
  {
      d->src = QGeoPositionInfoSource::createDefaultSource(this);

      if (d->src) {
          d->useGps = true;
          connect(d->src, SIGNAL(positionUpdated(QGeoPositionInfo)),
                  this, SLOT(positionUpdated(QGeoPositionInfo)));
          connect(d->src, SIGNAL(error(QGeoPositionInfoSource::Error)),
                  this, SLOT(positionError(QGeoPositionInfoSource::Error)));
          d->src->startUpdates();
      } else {
          d->useGps = false;
          d->city = "Brisbane";
          emit cityChanged();
          this->refreshWeather();
      }
  }

  void AppModel::positionUpdated(QGeoPositionInfo gpsPos)
  {
      d->coord = gpsPos.coordinate();

      if (!(d->useGps))
          return;

      queryCity();
  }

  void AppModel::queryCity()
  {
      //don't update more often then once a minute
      //to keep load on server low
      if (d->throttle.isValid() && d->throttle.elapsed() < d->minMsBeforeNewRequest ) {
          qCDebug(requestsLog) << "delaying query of city";
          if (!d->delayedCityRequestTimer.isActive())
              d->delayedCityRequestTimer.start();
          return;
      }
      qDebug(requestsLog) << "requested query of city";
      d->throttle.start();
      d->minMsBeforeNewRequest = (d->nErrors + 1) * d->baseMsBeforeNewRequest;

      QString latitude, longitude;
      longitude.setNum(d->coord.longitude());
      latitude.setNum(d->coord.latitude());

      QUrl url("http://api.openweathermap.org/data/2.5/weather");
      QUrlQuery query;
      query.addQueryItem("lat", latitude);
      query.addQueryItem("lon", longitude);
      query.addQueryItem("mode", "json");
      query.addQueryItem("APPID", d->app_ident);
      url.setQuery(query);
      qCDebug(requestsLog) << "submitting request";

      QNetworkReply *rep = d->nam->get(QNetworkRequest(url));
      // connect up the signal right away
      d->geoReplyMapper->setMapping(rep, rep);
      connect(rep, SIGNAL(finished()),
              d->geoReplyMapper, SLOT(map()));
  }

  void AppModel::positionError(QGeoPositionInfoSource::Error e)
  {
      Q_UNUSED(e);
      qWarning() << "Position source error. Falling back to simulation mode.";
      // cleanup insufficient QGeoPositionInfoSource instance
      d->src->stopUpdates();
      d->src->deleteLater();
      d->src = 0;

      // activate simulation mode
      d->useGps = false;
      d->city = "Brisbane";
      emit cityChanged();
      this->refreshWeather();
  }

  void AppModel::hadError(bool tryAgain)
  {
      qCDebug(requestsLog) << "hadError, will " << (tryAgain ? "" : "not ") << "rety";
      d->throttle.start();
      if (d->nErrors < 10)
          ++d->nErrors;
      d->minMsBeforeNewRequest = (d->nErrors + 1) * d->baseMsBeforeNewRequest;
      if (tryAgain)
          d->delayedCityRequestTimer.start();
  }

  void AppModel::handleGeoNetworkData(QObject *replyObj)
  {
      QNetworkReply *networkReply = qobject_cast<QNetworkReply*>(replyObj);
      if (!networkReply) {
          hadError(false); // should retry?
          return;
      }

      if (!networkReply->error()) {
          d->nErrors = 0;
          if (!d->throttle.isValid())
              d->throttle.start();
          d->minMsBeforeNewRequest = d->baseMsBeforeNewRequest;
          //convert coordinates to city name
          QJsonDocument document = QJsonDocument::fromJson(networkReply->readAll());

          QJsonObject jo = document.object();
          QJsonValue jv = jo.value(QStringLiteral("name"));

          const QString city = jv.toString();
          qCDebug(requestsLog) << "got city: " << city;
          if (city != d->city) {
              d->city = city;
              emit cityChanged();
              refreshWeather();
          }
      } else {
          hadError(true);
      }
      networkReply->deleteLater();
  }

  void AppModel::refreshWeather()
  {
      if (d->city.isEmpty()) {
          qCDebug(requestsLog) << "refreshing weather skipped (no city)";
          return;
      }
      qCDebug(requestsLog) << "refreshing weather";
      QUrl url("http://api.openweathermap.org/data/2.5/weather");
      QUrlQuery query;

      query.addQueryItem("q", d->city);
      query.addQueryItem("mode", "json");
      query.addQueryItem("APPID", d->app_ident);
      url.setQuery(query);

      QNetworkReply *rep = d->nam->get(QNetworkRequest(url));
      // connect up the signal right away
      d->weatherReplyMapper->setMapping(rep, rep);
      connect(rep, SIGNAL(finished()),
              d->weatherReplyMapper, SLOT(map()));
  }

  static QString niceTemperatureString(double t)
  {
      return QString::number(qRound(t-ZERO_KELVIN)) + QChar(0xB0);
  }

  void AppModel::handleWeatherNetworkData(QObject *replyObj)
  {
      qCDebug(requestsLog) << "got weather network data";
      QNetworkReply *networkReply = qobject_cast<QNetworkReply*>(replyObj);
      if (!networkReply)
          return;

      if (!networkReply->error()) {
          foreach (WeatherData *inf, d->forecast)
              delete inf;
          d->forecast.clear();

          QJsonDocument document = QJsonDocument::fromJson(networkReply->readAll());

          if (document.isObject()) {
              QJsonObject obj = document.object();
              QJsonObject tempObject;
              QJsonValue val;

              if (obj.contains(QStringLiteral("weather"))) {
                  val = obj.value(QStringLiteral("weather"));
                  QJsonArray weatherArray = val.toArray();
                  val = weatherArray.at(0);
                  tempObject = val.toObject();
                  d->now.setWeatherDescription(tempObject.value(QStringLiteral("description")).toString());
                  d->now.setWeatherIcon(tempObject.value("icon").toString());
              }
              if (obj.contains(QStringLiteral("main"))) {
                  val = obj.value(QStringLiteral("main"));
                  tempObject = val.toObject();
                  val = tempObject.value(QStringLiteral("temp"));
                  d->now.setTemperature(niceTemperatureString(val.toDouble()));
              }
          }
      }
      networkReply->deleteLater();

      //retrieve the forecast
      QUrl url("http://api.openweathermap.org/data/2.5/forecast/daily");
      QUrlQuery query;

      query.addQueryItem("q", d->city);
      query.addQueryItem("mode", "json");
      query.addQueryItem("cnt", "5");
      query.addQueryItem("APPID", d->app_ident);
      url.setQuery(query);

      QNetworkReply *rep = d->nam->get(QNetworkRequest(url));
      // connect up the signal right away
      d->forecastReplyMapper->setMapping(rep, rep);
      connect(rep, SIGNAL(finished()), d->forecastReplyMapper, SLOT(map()));
  }

  void AppModel::handleForecastNetworkData(QObject *replyObj)
  {
      qCDebug(requestsLog) << "got forecast";
      QNetworkReply *networkReply = qobject_cast<QNetworkReply*>(replyObj);
      if (!networkReply)
          return;

      if (!networkReply->error()) {
          QJsonDocument document = QJsonDocument::fromJson(networkReply->readAll());

          QJsonObject jo;
          QJsonValue jv;
          QJsonObject root = document.object();
          jv = root.value(QStringLiteral("list"));
          if (!jv.isArray())
              qWarning() << "Invalid forecast object";
          QJsonArray ja = jv.toArray();
          //we need 4 days of forecast -> first entry is today
          if (ja.count() != 5)
              qWarning() << "Invalid forecast object";

          QString data;
          for (int i = 1; i<ja.count(); i++) {
              WeatherData *forecastEntry = new WeatherData();

              //min/max temperature
              QJsonObject subtree = ja.at(i).toObject();
              jo = subtree.value(QStringLiteral("temp")).toObject();
              jv = jo.value(QStringLiteral("min"));
              data.clear();
              data += niceTemperatureString(jv.toDouble());
              data += QChar('/');
              jv = jo.value(QStringLiteral("max"));
              data += niceTemperatureString(jv.toDouble());
              forecastEntry->setTemperature(data);

              //get date
              jv = subtree.value(QStringLiteral("dt"));
              QDateTime dt = QDateTime::fromMSecsSinceEpoch((qint64)jv.toDouble()*1000);
              forecastEntry->setDayOfWeek(dt.date().toString(QStringLiteral("ddd")));

              //get icon
              QJsonArray weatherArray = subtree.value(QStringLiteral("weather")).toArray();
              jo = weatherArray.at(0).toObject();
              forecastEntry->setWeatherIcon(jo.value(QStringLiteral("icon")).toString());

              //get description
              forecastEntry->setWeatherDescription(jo.value(QStringLiteral("description")).toString());

              d->forecast.append(forecastEntry);
          }

          if (!(d->ready)) {
              d->ready = true;
              emit readyChanged();
          }

          emit weatherChanged();
      }
      networkReply->deleteLater();
  }

  bool AppModel::hasValidCity() const
  {
      return (!(d->city.isEmpty()) && d->city.size() > 1 && d->city != "");
  }

  bool AppModel::hasValidWeather() const
  {
      return hasValidCity() && (!(d->now.weatherIcon().isEmpty()) &&
                                (d->now.weatherIcon().size() > 1) &&
                                d->now.weatherIcon() != "");
  }

  WeatherData *AppModel::weather() const
  {
      return &(d->now);
  }

  QQmlListProperty<WeatherData> AppModel::forecast() const
  {
      return *(d->fcProp);
  }

  bool AppModel::ready() const
  {
      return d->ready;
  }

  bool AppModel::hasSource() const
  {
      return (d->src != NULL);
  }

  bool AppModel::useGps() const
  {
      return d->useGps;
  }

  void AppModel::setUseGps(bool value)
  {
      d->useGps = value;
      if (value) {
          d->city = "";
          d->throttle.invalidate();
          emit cityChanged();
          emit weatherChanged();
      }
      emit useGpsChanged();
  }

  QString AppModel::city() const
  {
      return d->city;
  }

  void AppModel::setCity(const QString &value)
  {
      d->city = value;
      emit cityChanged();
      refreshWeather();
  }

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