[Interest] ListView/ListModel optimization

[Kevin Mcintyre]

Given code like below where JSON data is used to populate a ListModel
- I run into loading issues on mobile when the number of objects
returned is greater than a couple thousand.s


Once the item is rendered it performs as expected, but the time to
ready is often beyond user acceptance.


Any suggestions greatly appreciated.

 import QtQuick 2.5

import QtQuick.Window 2.2


Window {

    visible: true


    Repeater {

        model: ['url1','url2','url3']

        ListView {

            delegate: Image {

                source: src

            }

            model: ListModel {

                Component.onCompleted {

                    var xhr = new XMLHttpRequest();

                    xhr.onreadystatechange = (function(data) {

                        return function() {

                            if ( data.readyState == 4 ) {

                                console.log('answered:', url)

                                try {

                                    var js = eval('new Object(' +
data.responseText + ')')

                                    for (var x = 0; x < js.length;x++) {

                                        append({'src': js[x].src})

                                    }

                                } catch (err) {

                                    console.log('error:', modelData, err);

                                }

                            }

                        }

                    })(xhr);

                    console.log('request:', url)

                    xhr.open('GET', modelData, true);

                    xhr.setRequestHeader('accept','application/json')

                    xhr.send('');

                }

            }

        }

    }

}
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