QML access properties of elements in list - qml

Question

I have a list of MapPolyline and I try to save dynamically added objects into this list. well It works but when I try to get the objects in list it does not work. it says TypeError: Cannot read property of undefined Here is my code
property list<MapPolyline> lines
var component;
var sprite;
component = Qt.createComponent("lineStringComponent.qml");
sprite = component.createObject(window,{"id": "button1"});
sprite.addCoordinate(QtPositioning.coordinate(currentgcppoint.lat, currentgcppoint.lon));
sprite.addCoordinate(gcppoint);
map.addMapItem(sprite)
lines.push(sprite)
gcps.push(currentgcppoint)
console.log("Added:", lines[1])
console.log("width:", lines[1].line.width)
Here is lineStringComponent.qml
import QtQuick 2.2
import QtLocation 5.6
import QtPositioning 5.6
MapPolyline {
id:polyline
line.width: 3
line.color: Qt.rgba(Math.random(),Math.random(),Math.random())
}
The consoles output is :
Added: undefined
TypeError: Cannot read property 'line' of undefined
It seems it has a delay when it tries to create a new object. How can we overcome this delay?

Answer 1

If I read your code correctly you only add 1 element to lines, and than you try to retrieve the second element of lines with line[1]. This is obviously undefined.
Try to access the first element of lines with line[0].
Indices of JS arrays start with 0 (as in most languages).
If there would be a delay with object creation, than you could not alter any of its properties, which you do (sprite.addCoordinate(...))