QML MapView

Kory

Hello, I'm exploring use of MapView{} and it's almost working how I'd like it to. I've found that it can work within a ScrollView{} and so forth, without user scrolling down stopping the user from interacting with map unlike the Map{}

Suppose that we have a QML file called "StreetMap.qml"
I've tried to cut out the irrelevant code. Just picture it has nesting like this

Item {
    id: _map_container
    property var coordinate: QtPositioning.coordinate(latitude, longitude)

    Plugin  {
        id: myPlugin
    }


    MapView {
        anchors.fill: parent

        map {
            plugin: myPlugin
            center: _map_container.coordinate
            }
        }
}

The problem I'm having is if I add a MapQuickItem nested in our map {}

MapQuickItem {
            id: marker
            coordinate:  _map_container.coordinate
            anchorPoint.x: 10
            anchorPoint.y: 10

            sourceItem: Image {
                source: "qrc:/MapsModule/map_marker.png"
                width: 24
                height: 24
                fillMode: Image.PreserveAspectFit
                smooth: true
            }

            // Debugging: Log where the marker is placed
            Component.onCompleted: {
                console.log("Marker placed at latitude: " + _map_container.latitude + ", longitude: " + _map_container.longitude)
            }
        }

The map no longer renders. I see this error message

W/default : qrc:/MapsModule/StreetMap.qml:78 Cannot assign a value directly to a grouped property

If I have MapQuickItem nested in our MapView {}, not the map{} then the map renders and it says that the marker is at the latitude and longitude we want from our console.log but nothing is rendered on the screen at this position

If I have MapQuickItem nested in a Map {} (not a map{}) and there's no MapView {} at all then the Map{} and MapQuickItem{} renders on the screen but I lose the features provided from the MapView{} like the interactive movement

Perhaps it's not possible to have a MapQuickItem in a map in a map view or perhaps there's a problem with how I'm approaching this

Let me know if you have any idea what this "Cannot assign a value directly to a grouped property" means and if there's any way around it or whatever else might be making the map unavailable the moment we have our MapQuickItem{} in a map{} of a MapView{}

Kai Nickel

I think you should not try to redefine the map instance that is already contained in MapView.
Maybe this works:

MapView {
    id: myMapView
    map.plugin: myPlugin
    map.center: _map_container.coordinate
    ...

    MapQuickItem {
        parent: myMapView.map
        ...
    }
}

GrecKo

I think the problem is the grouped property syntax (map { ... }) as mentioned in the error message, try the following instead:

MapView {
    map: Map {
        MapQuickItem {}
    }
}

Kory

Hello, I tested it out

@GrecKo said in QML MapView:

map: Map

I saw this warning when trying that and it dies on run

Cannot assign object of type Map to  [incompatible-type]

Kai Nickel

I think it is correct for the MapQuickItems to be parented to the Map, not to the MapView.

What line actually is the one from the error message (StreetMap.qml:78)?

I do it this way, but it might be unrelated:

map.plugin: myPlugin
map.center: _map_container.coordinate

Kory

Hello Kai, I believe so too

@Kai-Nickel

Here's the exact output I see

Note that the complaint about the StackView is really a side effect of the other complaint of not being able to assign a value directly to a grouped property

In case, it's not possible, I also posted this as a suggestion
https://bugreports.qt.io/browse/QTBUG-133696

And have full code posted there as a .txt file

Perhaps if it's not possible too, I believe it might be possible to use a GeocodeModel {} and MapRoute {} to have it set-up so can show route between a beginning and end destination with both points marked on the map (but I'm new to using Qt Location so don't quote me on that). If so, that could be an alternative approach I could explore instead of attempting to render a single marker on the map with MapQuickItem {}

Kai Nickel

I think you should not try to redefine the map instance that is already contained in MapView.
Maybe this works:

MapView {
    id: myMapView
    map.plugin: myPlugin
    map.center: _map_container.coordinate
    ...

    MapQuickItem {
        parent: myMapView.map
        ...
    }
}

Kory

Thanks for the help, Kai, your way got rid of the grouped property error