I am trying to use the osm api via a QGeoServiceProvider and QGeoCodingManager to derive the latitude and longitude from a given physical address. Thereby I stumbled upon this Question, which seems to do exactly what I need.
However I want to implement this in a qt gui application as a separate function and I don' t understand what is happening in the connect. Could someone please explain or how I can modify it to get it to work in a function ?
cout << "Try service: " << "osm" << endl;
// choose provider
QGeoServiceProvider qGeoService("osm");
QGeoCodingManager *pQGeoCoder = qGeoService.geocodingManager();
if (!pQGeoCoder) {
cerr
<< "GeoCodingManager '" << "osm"
<< "' not available!" << endl;
}
QLocale qLocaleC(QLocale::C, QLocale::AnyCountry);
pQGeoCoder->setLocale(qLocaleC);
// build address
QGeoAddress qGeoAddr;
qGeoAddr.setCountry(QString::fromUtf8("Germany"));
qGeoAddr.setPostalCode(QString::fromUtf8("88250"));
qGeoAddr.setCity(QString::fromUtf8("Weingarten"));
qGeoAddr.setStreet(QString::fromUtf8("Heinrich-Hertz-Str. 6"));
QGeoCodeReply *pQGeoCode = pQGeoCoder->geocode(qGeoAddr);
if (!pQGeoCode) {
cerr << "GeoCoding totally failed!" << endl;
}
cout << "Searching..." << endl;
QObject::connect(pQGeoCode, &QGeoCodeReply::finished,
[&qGeoAddr, pQGeoCode](){
cout << "Reply: " << pQGeoCode->errorString().toStdString() << endl;
switch (pQGeoCode->error()) {
#define CASE(ERROR) \
case QGeoCodeReply::ERROR: cerr << #ERROR << endl; break
CASE(NoError);
CASE(EngineNotSetError);
CASE(CommunicationError);
CASE(ParseError);
CASE(UnsupportedOptionError);
CASE(CombinationError);
CASE(UnknownError);
#undef CASE
default: cerr << "Undocumented error!" << endl;
}
if (pQGeoCode->error() != QGeoCodeReply::NoError) return;
// eval. result
QList<QGeoLocation> qGeoLocs = pQGeoCode->locations();
cout << qGeoLocs.size() << " location(s) returned." << endl;
for (QGeoLocation &qGeoLoc : qGeoLocs) {
qGeoLoc.setAddress(qGeoAddr);
QGeoCoordinate qGeoCoord = qGeoLoc.coordinate();
cout
<< "Lat.: " << qGeoCoord.latitude() << endl
<< "Long.: " << qGeoCoord.longitude() << endl
<< "Alt.: " << qGeoCoord.altitude() << endl;
}
});
So I just removed the QApplication part because I dont have this reference in a function. As a result i get:
Qt Version: 5.10.0
Try service: osm
Searching...
but no coordinates. I assume the connection to where the lat and lon data is acquired fails. But as I mentioned I dont understand the connect here. Any help is appreciated
EDIT so I tried to build a connect to catch the finished Signal as suggested. The code now looks like this:
QGeoServiceProvider qGeoService("osm");
QGeoCodingManager *pQGeoCoder = qGeoService.geocodingManager();
if (!pQGeoCoder) {
cerr
<< "GeoCodingManager '" << "osm"
<< "' not available!" << endl;
}
QLocale qLocaleC(QLocale::C, QLocale::AnyCountry);
pQGeoCoder->setLocale(qLocaleC);
// build address
//QGeoAddress qGeoAddr;
qGeoAddr.setCountry(QString::fromUtf8("Germany"));
qGeoAddr.setPostalCode(QString::fromUtf8("88250"));
qGeoAddr.setCity(QString::fromUtf8("Weingarten"));
qGeoAddr.setStreet(QString::fromUtf8("Heinrich-Hertz-Str. 6"));
this->pQGeoCode = pQGeoCoder->geocode(qGeoAddr);
if (!pQGeoCode) {
cerr << "GeoCoding totally failed!" << endl;
}
cout << "Searching..." << endl;
connect(pQGeoCode,SIGNAL(finished()),this,SLOT(getlonlat()));
With the Slot:
void MainWindow::getlonlat()
{
QList<QGeoLocation> qGeoLocs = pQGeoCode->locations();
cout << qGeoLocs.size() << " location(s) returned." << endl;
for (QGeoLocation &qGeoLoc : qGeoLocs) {
qGeoLoc.setAddress(qGeoAddr);
QGeoCoordinate qGeoCoord = qGeoLoc.coordinate();
cout
<< "Lat.: " << qGeoCoord.latitude() << endl
<< "Long.: " << qGeoCoord.longitude() << endl
<< "Alt.: " << qGeoCoord.altitude() << endl;
}
}
However the finished signal doesn't get triggered. Therefore the result is the same. EDIT
Implementing the Code from your Gui Answer:
MainWindow.cpp:
#include "mainwindow.h"
#include "ui_mainwindow.h"
// standard C++ header:
#include <iostream>
#include <sstream>
// Qt header:
#include <QGeoAddress>
#include <QGeoCodingManager>
#include <QGeoCoordinate>
#include <QGeoLocation>
#include <QGeoServiceProvider>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
QGeoServiceProvider *pQGeoProvider = nullptr;
ui->setupUi(this);
qDebug() << "Qt Version:" << QT_VERSION_STR;
// main application
//QApplication app(argc, argv);
// install signal handlers
QObject::connect(this->ui->qBtnInit, &QPushButton::clicked,
[&]() {
if (pQGeoProvider) delete pQGeoProvider;
std::ostringstream out;
pQGeoProvider = init(out);
log(out.str());
});
QObject::connect(this->ui->qBtnFind, &QPushButton::clicked,
[&]() {
// init geo coder if not yet done
if (!pQGeoProvider) {
std::ostringstream out;
pQGeoProvider = init(out);
log(out.str());
if (!pQGeoProvider) return; // failed
}
// fill in request
QGeoAddress *pQGeoAddr = new QGeoAddress;
pQGeoAddr->setCountry(this->ui->qTxtCountry->text());
pQGeoAddr->setPostalCode(this->ui->qTxtZipCode->text());
pQGeoAddr->setCity(this->ui->qTxtCity->text());
pQGeoAddr->setStreet(this->ui->qTxtStreet->text());
QGeoCodeReply *pQGeoCode
= pQGeoProvider->geocodingManager()->geocode(*pQGeoAddr);
if (!pQGeoCode) {
delete pQGeoAddr;
log("GeoCoding totally failed!\n");
return;
}
{ std::ostringstream out;
out << "Sending request for:\n"
<< pQGeoAddr->country().toUtf8().data() << "; "
<< pQGeoAddr->postalCode().toUtf8().data() << "; "
<< pQGeoAddr->city().toUtf8().data() << "; "
<< pQGeoAddr->street().toUtf8().data() << "...\n";
log(out.str());
}
// install signal handler to process result later
QObject::connect(pQGeoCode, &QGeoCodeReply::finished,
[&,pQGeoAddr, pQGeoCode]() {
// process reply
std::ostringstream out;
out << "Reply: " << pQGeoCode->errorString().toStdString() << '\n';
switch (pQGeoCode->error()) {
case QGeoCodeReply::NoError: {
// eval result
QList<QGeoLocation> qGeoLocs = pQGeoCode->locations();
out << qGeoLocs.size() << " location(s) returned.\n";
for (QGeoLocation &qGeoLoc : qGeoLocs) {
qGeoLoc.setAddress(*pQGeoAddr);
QGeoCoordinate qGeoCoord = qGeoLoc.coordinate();
out
<< "Lat.: " << qGeoCoord.latitude() << '\n'
<< "Long.: " << qGeoCoord.longitude() << '\n'
<< "Alt.: " << qGeoCoord.altitude() << '\n';
}
} break;
#define CASE(ERROR) \
case QGeoCodeReply::ERROR: out << #ERROR << '\n'; break
CASE(EngineNotSetError);
CASE(CommunicationError);
CASE(ParseError);
CASE(UnsupportedOptionError);
CASE(CombinationError);
CASE(UnknownError);
#undef CASE
default: out << "Undocumented error!\n";
}
// log result
log(out.str());
// clean-up
delete pQGeoAddr;
/* delete sender in signal handler could be lethal
* Hence, delete it later...
*/
pQGeoCode->deleteLater();
});
});
// fill in a sample request with a known address initially
this->ui->qTxtCountry->setText(QString::fromUtf8("Germany"));
this->ui->qTxtZipCode->setText(QString::fromUtf8("88250"));
this->ui->qTxtCity->setText(QString::fromUtf8("Weingarten"));
this->ui->qTxtStreet->setText(QString::fromUtf8("Danziger Str. 3"));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::log(const QString &qString)
{
this->ui->qTxtLog->setPlainText(this->ui->qTxtLog->toPlainText() + qString);
this->ui->qTxtLog->moveCursor(QTextCursor::End);
}
void MainWindow::log(const char *text)
{
log(QString::fromUtf8(text));
}
void MainWindow::log(const std::string &text)
{
log(text.c_str());
}
QGeoServiceProvider* MainWindow::init(std::ostream &out)
{
// check for available services
QStringList qGeoSrvList
= QGeoServiceProvider::availableServiceProviders();
for (QString entry : qGeoSrvList) {
out << "Try service: " << entry.toStdString() << '\n';
// choose provider
QGeoServiceProvider *pQGeoProvider = new QGeoServiceProvider(entry);
if (!pQGeoProvider) {
out
<< "ERROR: GeoServiceProvider '" << entry.toStdString()
<< "' not available!\n";
continue;
}
QGeoCodingManager *pQGeoCoder = pQGeoProvider->geocodingManager();
if (!pQGeoCoder) {
out
<< "ERROR: GeoCodingManager '" << entry.toStdString()
<< "' not available!\n";
delete pQGeoProvider;
continue;
}
QLocale qLocaleC(QLocale::C, QLocale::AnyCountry);
pQGeoCoder->setLocale(qLocaleC);
out << "Using service " << entry.toStdString() << '\n';
return pQGeoProvider; // success
}
out << "ERROR: No suitable GeoServiceProvider found!\n";
return nullptr; // all attempts failed
}
The main.cpp:
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
And here the Header File for the MainWindow:
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
// standard C++ header:
#include <iostream>
#include <sstream>
// Qt header:
#include <QGeoAddress>
#include <QGeoCodingManager>
#include <QGeoCoordinate>
#include <QGeoLocation>
#include <QGeoServiceProvider>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
virtual ~MainWindow();
void log(const QString &qString);
void log(const char *text);
void log(const std::string &text);
QGeoServiceProvider* init(std::ostream &out);
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
