An example of how to call a JSON webservice directly from BlackBerry 10 Cascades QML. This gist also shows how to convert Date strings purely in QML. This gist is part of this blogpost: http://www.shadowmedia.be/bbdevbe/2013/01/13/listing-json-data-from-a-webservice-using-pure-qml/.

gistfile1.js

import bb.cascades 1.0
import bb.data 1.0 // don't forget to add "LIBS += -lbbdata" to your .pro file!

Page {
    id: pgDetail
    
    actions: [
        ActionItem {
            title: qsTr("Refresh")
            onTriggered: {
                dataSource.load()
            }
        }
    ]
    paneProperties: NavigationPaneProperties {
        backButton: ActionItem {
            onTriggered: {
                navigationPane.pop()
            }
        }
    }
    Container {
        ListView {
            dataModel: dataModel
            
            listItemComponents: [
                ListItemComponent {
                    type: "item"
                    
                    StandardListItem {
                        title: convertDate(ListItemData.someDateField) // call a function
                        description: ListItemData.someField
                        imageSpaceReserved: false
                        
                        function convertDate(toBeConvertedDate) {
                            console.debug("registration date: " + toBeConvertedDate);
                            console.debug("type of registration date: " + typeof toBeConvertedDate);
                            var workingDate = new Date();
                            workingDate.setFullYear(toBeConvertedDate.substring(0,4));
                            console.debug("year: " + toBeConvertedDate.substring(0,4));
                            workingDate.setMonth(toBeConvertedDate.substring(5,7) - 1);
                            console.debug("month: " + toBeConvertedDate.substring(5,7));
                            workingDate.setDate(toBeConvertedDate.substring(8,10));
                            console.debug("date: " + toBeConvertedDate.substring(8,10));
                            
                            workingDate.setHours(toBeConvertedDate.substring(11, 13));
                            console.debug("hours: " + toBeConvertedDate.substring(11, 13));
                            workingDate.setMinutes(toBeConvertedDate.substring(14,16));
                            console.debug("minutes: " + toBeConvertedDate.substring(14,16));
                            workingDate.setSeconds(toBeConvertedDate.substring(17,19));
                            console.debug("seconds: " + toBeConvertedDate.substring(17,19));
                            
                            //var toBeReturnedDate = Qt.formatDateTime(workingDate, "yyyy/MM/dd HH:mm:ss");
                            var toBeReturnedDate = Qt.formatDateTime(workingDate, "ddd dd MMM yyyy");
                                                        
                            console.debug("toBeReturnedDate: " + toBeReturnedDate);
                            return toBeReturnedDate;
                        }
                    }
                    
                }
            ]
        }
    }
    
    attachedObjects: [
        GroupDataModel {
            id: dataModel
            sortingKeys: ["someImportantFieldName"]
            sortedAscending: false
            grouping: ItemGrouping.None
        },
        DataSource {
            id: dataSource
            source: "http://some.url.that.returns.json"
            type: DataSourceType.Json
            
            onDataLoaded: {
                dataModel.clear()
                dataModel.insertList(data)
            }
        }
    ]
    
    onCreationCompleted: {
        dataSource.load()
    }
}