[Interest] How to dynamically add a MapItemView to a Map?
Paolo Angelelli
paolo.angelelli at qt.io
Wed Sep 7 16:15:20 CEST 2016
I see i forgot to answer one question, about delegates and addMapItem.
The problem in your case is that your delegate is incorrect.
The delegate of a MapItemView must be a Map Item subclass,
that means MapCircle MapRectangle MapPolygon etc.
If you have it wrapped into a Component, when this component gets
addMapItem'd to the map, it will be also skipped.
try removing the Component wrapper, and you'll see it works.
(and by the way in your example you miss a window, so the example
doesn't work as is)
best,
Paolo
On Tue, 6 Sep 2016 22:53:31 +0530
Kishore J <kitts.mailinglists at gmail.com> wrote:
> Done. https://bugreports.qt.io/browse/QTBUG-55782
>
> Given the limitation, I think my immediate alternative is to create a
> MapItemView like component that is instantiated outside and write
> code in the map that calls addMapItem and removeMapItem on the map as
> and when the list is modified. To the drawing board...
>
> Is the patch for the bug requiring to call addMapItem for each item
> in the MapItemView delegate is due for the next release? i.e. 5.8?
>
> How about the bug relating to the setting the center of the map? Its
> easy to work around but I want to know if it's me doing something
> wrong. --
> Regards,
> Kishore
>
> On Tue, Sep 6, 2016 at 9:25 PM, Paolo Angelelli
> <paolo.angelelli at qt.io> wrote:
>
> > On Tue, 6 Sep 2016 19:04:34 +0530
> > Kishore J <kitts.mailinglists at gmail.com> wrote:
> >
> > > Hi
> > >
> > > I am inching forward with using QML maps in my C++ application.
> > > Now i'm interested in dynamically adding multiple MapItemView
> > > objects to a given map.
> > >
> > >
> > > import QtQuick 2.5
> > > import QtLocation 5.6
> > >
> > > Map {
> > > id: map
> > > objectName: "MyMap"
> > > // zoomLevel: (maximumZoomLevel - minimumZoomLevel)/2
> > > zoomLevel: minimumZoomLevel
> > >
> > > plugin: Plugin {
> > > name: "here"
> > > PluginParameter {name: "here.app_id"; value: "xxxxx"}
> > > PluginParameter {name: "here.token"; value: "xxxxx"}
> > > }
> > > // activeMapType: supportedMapTypes[3]
> > > center {
> > > latitude: 10
> > > longitude: 20
> > > }
> > >
> > > MapCircle {
> > > id: staticCircle
> > > center {
> > > latitude: 5
> > > longitude: 10
> > > }
> > > radius: 500000.0
> > > color: 'yellow'
> > > border.width: 4
> > > border.color: 'yellow'
> > > Component.onCompleted: {
> > > console.debug("Loaded static MapCircle")
> > > console.debug(center + ' radius: ' + radius)
> > > }
> > > Component.onDestruction: {
> > > console.debug("Unloaded static MapCircle")
> > > }
> > > }
> > >
> > > MapItemView {
> > > id: mapitemview
> > > objectName: "MyMapItemView"
> > > model: ListModel {
> > > id: list
> > > ListElement{lat: 10; lon: 20; rad: 800000}
> > > ListElement{lat: 30; lon: 40; rad: 700000}
> > > }
> > > delegate: Component {
> > > id: delegate
> > >
> > > MapCircle {
> > > id: dynmapcircle
> > > center {
> > > latitude: lat;
> > > longitude: lon;
> > > }
> > > radius: 500000.0
> > > color: 'black'
> > > border.width: 4
> > > border.color: 'black'
> > > Component.onCompleted: {
> > > console.count("Loaded a MapCircle")
> > > map.addMapItem(dynmapcircle)
> > > }
> > > }
> > > }
> > >
> > > Component.onCompleted: {
> > > console.debug("Loaded first MapItemView")
> > > console.debug(model.count)
> > > }
> > > Component.onDestruction: {
> > > console.debug("Unloaded first MapItemView")
> > > }
> > > }
> > >
> > > MapItemView {
> > > id: mapitemview2
> > > objectName: "MyMapItemView2"
> > > model: ListModel {
> > > id: list2
> > > ListElement{lat: -10; lon: 20; rad: 800000}
> > > ListElement{lat: -30; lon: 40; rad: 700000}
> > > }
> > > delegate: Component {
> > > id: delegate2
> > >
> > > MapCircle {
> > > id: dynmapcircle2
> > > center {
> > > latitude: lat;
> > > longitude: lon;
> > > }
> > > radius: 500000.0
> > > color: 'blue'
> > > border.width: 4
> > > border.color: 'blue'
> > > Component.onCompleted: {
> > > console.count("Loaded a MapCircle2")
> > > map.addMapItem(dynmapcircle2)
> > > }
> > > }
> > > }
> > >
> > > Component.onCompleted: {
> > > console.debug("Loaded second MapItemView")
> > > }
> > > Component.onDestruction: {
> > > console.debug("Unloaded second MapItemView")
> > > }
> > > }
> > >
> > > Component.onCompleted:{
> > > center.latitude = 10
> > > center.longitude = 20
> > > console.debug('Loaded map ' + map.center)
> > > }
> > > Component.onDestruction:{
> > > console.debug('Unloaded map')
> > > }
> > > }
> > >
> > > Further, i do not understand why i have to call the
> > > map.addMapItem() function for each MapItem. I suspect that, that
> > > is the source of my problem. I am currently able to define a
> > > separate qml file containing the second MapItemView which i
> > > instantiate in C++ and set the map as it's parent but that does
> > > not work.
> > >
> > > Any help would be appreciated.
> > > --
> > > Regards,
> > > Kishore
> > >
> > > PS: I also seem to be facing another issue where the center value
> > > specified in the map initialization does not work and I have to
> > > set the center in the onCompleted() slot. Funnily, it only
> > > considers the Latitude or Longitude value in the initialization
> > > depending on which is first specified!
> >
> > Hi, for the first question, the answer is "you can't".
> > This is a limitation of the current API, and something that might be
> > worthwile extending.
> > So feel free to send a feature request to jira.
> >
> > For the second question, please have a look if the (now merged)
> > patch fixes your bug
> >
> > best,
> > Paolo
> > _______________________________________________
> > Interest mailing list
> > Interest at qt-project.org
> > http://lists.qt-project.org/mailman/listinfo/interest
> >
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