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Retrieve Location Using Qt Mobility: Difference between revisions

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{{Cleanup | reason=Auto-imported from ExpressionEngine.}}
{{LangSwitch}}
[[Category:Developing with Qt::QtMobility]]
[[Category:Developing with Qt::QtMobility]]
[[Category:HowTo]]
[[Category:HowTo]]
[[Category:Snippets]]
[[Category:Snippets::Misc]]
[[Category:Tutorial]]
[[Category:Tutorial]]
[toc align_right="yes" depth="4"]
'''English''' [[Retrieve_Location_Using_Qt_Mobility_Bulgarian|Български]]


= Retrieve Location Using Qt Mobility =
= Retrieve Location Using Qt Mobility =
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== Overview ==
== Overview ==


The provided code snippet shows how to retrieve location using Qt Mobility class "QGeoPositionInfoSource":http://doc.qt.nokia.com/qtmobility-1.1.0-beta/qgeopositioninfosource.html. When the position is retrieved the location coordinates (latitude and longitude) are displayed on the screen. The given example has been tested on Nokia E7 with Symbian^3.
The provided code snippet shows how to retrieve location using Qt Mobility class [http://doc.qt.nokia.com/qtmobility-1.1.0-beta/qgeopositioninfosource.html QGeoPositionInfoSource]. When the position is retrieved the location coordinates (latitude and longitude) are displayed on the screen. The given example has been tested on Nokia E7 with Symbian^3.


The following "positioning methods":http://doc.qt.nokia.com/qtmobility-1.1.0-beta/qgeopositioninfosource.html#PositioningMethod-enum can be used:
The following [http://doc.qt.nokia.com/qtmobility-1.1.0-beta/qgeopositioninfosource.html#PositioningMethod-enum positioning methods] can be used:
* '''SatellitePositioningMethods''' - Satellite-based positioning methods such as GPS.
* '''SatellitePositioningMethods''' - Satellite-based positioning methods such as GPS.
* '''NonSatellitePositioningMethods''' - Other positioning methods.
* '''NonSatellitePositioningMethods''' - Other positioning methods.
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=== Project File ===
=== Project File ===


Qt Mobility should be included at the project file. Additionally if the application is targeting Symbian devices Location should be added as a "capability":http://developer.qt.nokia.com/wiki/Symbian_Capabilities.
Qt Mobility should be included at the project file. Additionally if the application is targeting Symbian devices Location should be added as a [http://developer.qt.nokia.com/wiki/Symbian_Capabilities capability].


<code>
<code>
symbian:TARGET.CAPABILITY ''= NetworkServices Location
symbian:TARGET.CAPABILITY += NetworkServices Location


CONFIG''= mobility
CONFIG += mobility
MOBILITY += location
MOBILITY += location
</code>
</code>
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#define MAINWINDOW_H
#define MAINWINDOW_H


#include <QtGui/QMainWindow>
#include <QMainWindow>
#include <QGeoPositionInfo>
#include <QGeoPositionInfo>
#include <QGeoPositionInfoSource>
#include <QGeoPositionInfoSource>
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public:
public:


explicit MainWindow(QWidget '''parent = 0);
explicit MainWindow(QWidget *parent = 0);


  virtual ~MainWindow();
  virtual ~MainWindow();


public slots:
public slots:
  /'''*
  /*
  * Called when the current position is updated.
  * Called when the current position is updated.
  *
  *
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private:
private:
  /'''*
  /*
  * Start listening for position changes
  * Start listening for position changes
  *
  *
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private:
private:
  QGeoPositionInfoSource''' m_pLocationInfo;
  QGeoPositionInfoSource* m_pLocationInfo;


QLabel* m_pLabel;
QLabel* m_pLabel;
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#include <QDesktopWidget>
#include <QDesktopWidget>


#include <QtCore/QCoreApplication>
#include <QCoreApplication>


#include <QDebug>
#include <QDebug>


MainWindow::MainWindow(QWidget '''parent)
MainWindow::MainWindow(QWidget *parent)
  : QMainWindow(parent), m_pLocationInfo(NULL), m_pLabel(NULL)
  : QMainWindow(parent), m_pLocationInfo(NULL), m_pLabel(NULL)
{
{
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</code>
</code>


h2. Troubleshooting
== Troubleshooting ==
 
''' 'QGeoPositionInfo' has not been declared
''' 'QGeoPositionInfo' has not been declared


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* AllPositioningMethods does not work as expected
* AllPositioningMethods does not work as expected


This is a known "critical bug that affects Qt Mobility 1.1.2":https://bugreports.qt.io/browse/QTMOBILITY-1550 Please check the provided link for details.
This is a known [https://bugreports.qt.io/browse/QTMOBILITY-1550 critical bug that affects Qt Mobility 1.1.2] Please check the provided link for details.


== See Also ==
== See Also ==

Latest revision as of 12:09, 28 November 2016

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Retrieve Location Using Qt Mobility

Overview

The provided code snippet shows how to retrieve location using Qt Mobility class QGeoPositionInfoSource. When the position is retrieved the location coordinates (latitude and longitude) are displayed on the screen. The given example has been tested on Nokia E7 with Symbian^3.

The following positioning methods can be used:

  • SatellitePositioningMethods - Satellite-based positioning methods such as GPS.
  • NonSatellitePositioningMethods - Other positioning methods.
  • AllPositioningMethods - All positioning methods.

The example application is using NonSatellitePositioningMethods.

Code Snippet

Project File

Qt Mobility should be included at the project file. Additionally if the application is targeting Symbian devices Location should be added as a capability.

symbian:TARGET.CAPABILITY += NetworkServices Location

CONFIG += mobility
MOBILITY += location

Header

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QGeoPositionInfo>
#include <QGeoPositionInfoSource>
#include <QLabel>

// QtMobility namespace
QTM_USE_NAMESPACE

namespace Ui {
 class MainWindow;
}

class MainWindow : public QMainWindow
{
 Q_OBJECT
public:

explicit MainWindow(QWidget *parent = 0);

 virtual ~MainWindow();

public slots:
 /*
 * Called when the current position is updated.
 *
 *

return nothing

*/
void positionUpdated(QGeoPositionInfo geoPositionInfo);

private:

/*
* Start listening for position changes
*

*

return nothing
 */
 void startLocationAPI();

private:
 QGeoPositionInfoSource* m_pLocationInfo;

QLabel* m_pLabel;

};

#endif // MAINWINDOW_H

Source

#include "mainwindow.h"

#include <QGeoCoordinate>
#include <QApplication>
#include <QDesktopWidget>

#include <QCoreApplication>

#include <QDebug>

MainWindow::MainWindow(QWidget *parent)
 : QMainWindow(parent), m_pLocationInfo(NULL), m_pLabel(NULL)
{
 m_pLabel = new QLabel("",this);
 m_pLabel->setGeometry(QApplication::desktop()->screenGeometry());
 startLocationAPI();
}

MainWindow::~MainWindow()
{

}

void MainWindow::startLocationAPI()
{
 // Obtain the location data source if it is not obtained already
 if (!m_pLocationInfo)
 {
 m_pLocationInfo =
 QGeoPositionInfoSource::createDefaultSource(this);

 //Select positioning method
 m_pLocationInfo->setPreferredPositioningMethods(QGeoPositionInfoSource::NonSatellitePositioningMethods);

 // When the position is changed the positionUpdated function is called
 connect(m_pLocationInfo, SIGNAL (positionUpdated(QGeoPositionInfo)),
 this, SLOT (positionUpdated(QGeoPositionInfo)));

 // Start listening for position updates
 m_pLocationInfo->startUpdates();
 }
}

void MainWindow::positionUpdated(QGeoPositionInfo geoPositionInfo)
{
 if (geoPositionInfo.isValid())
 {
 // Get the current location coordinates
 QGeoCoordinate geoCoordinate = geoPositionInfo.coordinate();
 qreal latitude = geoCoordinate.latitude();
 qreal longitude = geoCoordinate.longitude();

 m_pLabel->setText( QString("Latitude: %1 Longitude: %2").arg(latitude).arg(longitude) );
 }
}

Troubleshooting

'QGeoPositionInfo' has not been declared

All required header files must be included and the Qt Mobility namespace should be specified.

#include <QGeoPositionInfo>
#include <QGeoPositionInfoSource>

// QtMobility namespace
QTM_USE_NAMESPACE
  • AllPositioningMethods does not work as expected

This is a known critical bug that affects Qt Mobility 1.1.2 Please check the provided link for details.

See Also