Minimal map qml example in QWidget application

Dragoon

Inspired by the minimal map example I'm trying to embeed a qml map inside a standard QWidget application.
I defined the following qml script (map.qml):

import QtQuick 2.15
import QtLocation 5.6
import QtPositioning 5.6

Item {
   visible: true
   anchors.fill: parent

   Plugin {
       id: mapPlugin
       name: "osm"
   }

   Map {
       anchors.fill: parent
       plugin: mapPlugin
       center: QtPositioning.coordinate(44.17327, 9.87352)
       zoomLevel: 14
   }
}

Added the following method to Mainwindow class:

void MainWindow::init_view(const QUrl& source)
{
    mView = new QQuickView;

    mView->setSource(source);

    mWidget = QWidget::createWindowContainer(mView, this);

    setCentralWidget(mWidget);
}

Such method is called here (in main.cpp):

    MainWindow w;
    w.init_view(QUrl("qrc:/map.qml"));
    w.show();

The app runs and correctly show the map (as did the original minimal map example), but looking into Application Output window I got this warning line:

QObject::connect(QQuickWindow, QDeclarativeGeoMap): invalid nullptr parameter

What's the problem? Do I need to worry about this?

SGaist

Hi,

What if you use QQuickWidget directly ?

Dragoon

What do you mean?
This?

setCentralWidget(mView);

It doesn't work, setCentralWidget() only accept QWidget* params.
If I cast it to QWidget* the application crashes with the following output:

14:52:22: Starting build-maptest-Desktop_Qt_5_15_2_GCC_64bit-Debug/maptest...
QML debugging is enabled. Only use this in a safe environment.
QObject::connect(QQuickWindow, QDeclarativeGeoMap): invalid nullptr parameter
14:52:23: build-maptest-Desktop_Qt_5_15_2_GCC_64bit-Debug/maptest crashed.

SGaist

Rather than make the QQuickView danse, directly use QQuickWidget.

Dragoon

@SGaist

I tried with this:

mView = new QQuickWidget;

mView->setSource(source);
mView->show();

setCentralWidget(mView);

Got the the same messages on application output as if I was using QQuickView (nullptr warning included), no application crash but no map was shown.

SGaist

Might be a silly question but are you including the proper modules in your .pro file ?