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inside custom component

Native Development

Posts: 74
Registered: ‎12-17-2009
My Device: Z30
My Carrier: O2

Noob question regarding following sample apps



I am trying to learn to create my own app by using the FilteredDataModel, which uses the VegetablesModel as a Custom Model and I am faced with a few questions. I have used mostly http://supportforums.blackberry.com/t5/Native-Development-Knowledge/Using-a-Custom-DataModel-to-Filt... though it differs slightly from the actual sample code I downloaded.


1) The sample app creates the list in main.qml, but I do not want to do so as I want to put it in another page customlist.qml (I also would like another list so I do not want it to interfer with other lists). So I am not sure if I should put the following code in the app?


The app sample creates an app.cpp that contains:


App::App(QObject *parent)
    : QObject(parent)
    , m_model(0)
    // Create the source data model
    VegetablesDataModel *vegetablesModel = new VegetablesDataModel(this);

    // Create the filtered data model and pass the source model
    m_model = new FilteredDataModel(vegetablesModel, this);

    QmlDocument *qml = QmlDocument::create("asset:///main.qml").parent(this);
    qml->setContextProperty("_model", m_model);
    qml->setContextProperty("_app", this);

    AbstractPane* root = qml->createRootObject<AbstractPane>();
//! [0]

//! [1]
void App::selectionChanged(const QVariantList &indexPath, bool selected)
    if (indexPath.size() != 1 || !selected)
        return; // Not interested

    // Selected a header item!
    const int selection = indexPath[0].toInt();

    // Toggle the expanded state of the selected header
    m_model->expandHeader(selection, !m_model->isHeaderExpanded(selection));
//! [1]

Re: Source DataModel


I do not want to use a custom list model but would rather use a XMLDataModel/SQL. But I am not sure how I can do this? 


 Re: [0]

Would it be correct to instead put:


	QmlDocument *qml = QmlDocument::create("asset://main.qml").parent(this);
	qml->setContextProperty("_app", this);

	QmlDocument *qml = QmlDocument::create("asset://CustomList.qml").parent(this);
	qml->setContextProperty("myList", m_model);

 And should I still put them inside the app.cpp or create a CustomList.app?


Re: [1] App:: selectionChanged

I am afraid that this will apply to all 'selectionChanged'. How can I make sure it only applies to that specific Custom list?



In filtereddatamodel.cpp


One of the functions of the filteredmodelclass contains the ::data

QVariant FilteredDataModel::data(const QVariantList& indexPath)
    if (indexPath.size() == 1) { // header item
        // Enrich the original data of the source model with additional data about expanded state
        QVariantMap data;
        data["data"] = m_sourceDataModel->data(indexPath);
        data["expanded"] = (indexPath[0] == m_expandedIndex);

        return data;
    } else {
        // Pass through the data from the source model
        return m_sourceDataModel->data(indexPath);

 which I understand can then be called from main.qml's Listview as Listdatamodel.data, and Listdatamodel.expanded.


The thing is, I have a more complicated datamodel. How can I map the QVariantMap data to specific information on my XML/SQL (have not decided which one to use)?


e.g. I want to have: data["id"], data["title"], data["status"] to use in my ListView.



QString FilteredDataModel::itemType


I would like to create 3 levels of list. Can I use:


switch (indexPath.size()) {
return QLatin1String("header");
case 2:
return QLatin1String("subheader");
return QLatin1String("item");

 And use them in my ListView like:

            listItemComponents: [
                ListItemComponent {
                    id: header
                    type: "header"
                    objectName: "header"

                ListItemComponent {
                    id: subcategory
                    type: "subheader"
                    objectName: "subheader"

                ListItemComponent {
                    id: item
                    type: "item"
                    objectName: "item"




Thanks and apologies for the long post!!!

All Replies
Posts: 265
Registered: ‎01-02-2011
My Device: Z30, PlayBook
My Carrier: AT&T

Re: Noob question regarding following sample apps

Are you still going to use the main.qml as the starting page?


Then you don't need to do this part, you still can call _app from the other pages the same.

QmlDocument *qml = QmlDocument::create("asset://CustomList.qml").parent(this);
	qml->setContextProperty("myList", m_model);

From the documentation, you can create 2 levels of list, but I don't think you can create 3 levels.  

You don't need to create 2 lists, but just set your datamodel to sort on the first level ("header").

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