Accessing role values using an index in a model

fcarney

I have QAbstractListModel object I am working with in my qml Action:

    onTriggered: {
            console.log("TransferRight")

            var index = acqparamsmodel.item.currentIndex
            var model = acqparammodelproxy.sourceModel
            var qindex = model.index(index,0)
            console.log(qindex)
            var modulename = model.data(qindex, model.nameRole)
            var name = model.data(qindex, model.moduleNameRole)
            console.log(modulename, name)
        }

I can get the index and I can call the data method. However, I am unsure of how to get the role integer for the call to data. I have used Q_ENUM on the enum with all the roles. There is also a roleNames function that will map the enum values to text names. I have tried calling data() with a the roleNames string instead of an integer and that doesn't work either. Worse comes to worse I could set global properties when a selection is made and fill those with the name and modulename. However, I really would like to know how to do this via that data call. I assume there are default roles like Qt.DisplayRole or some such, but I have custom roles and role indexes.

How do I get the custom role names/integers in QML?

fcarney

This is very frustrating. When editing the QML I can auto-complete the NameRole and ModuleNameRole on the acq_params object. However, it will not get that value when printing to console:

    onTriggered: {
            console.log("TransferRight")

            var index = acqparamsmodel.item.currentIndex
            //var model = acqparammodelproxy.sourceModel
            console.log(acqparammodelproxy.sourceModel)
            console.log(acq_params)
            console.log(acq_params.NameRole)
            console.log(acq_params.ModuleNameRole)
            console.log(AcqParamModel.NameRole)
            console.log(AcqParamModel.ModuleNameRole)
            var model = acqparammodelproxy
            console.log(acqparammodelproxy.NameRole)
            console.log(acqparammodelproxy.ModuleNameRole)
            var qindex = model.index(index,0)
            console.log(qindex)
            var modulename = model.data(qindex, AcqParamModel.NameRole)
            var name = model.data(qindex, AcqParamModel.ModuleNameRole)
            console.log(modulename, name)
        }

Output:

qml: TransferRight
qml: AcqParamModel(0x55ef6e768c90)
qml: AcqParamModel(0x55ef6e768c90)
qml: undefined
qml: undefined
qml: 386
qml: 391
qml: undefined
qml: undefined
qml: QModelIndex(0,0,0x55ef75001c20,StreamPrinter::AcqParamModelProxy(0x55ef6e85a9b0))
qml: Position AVC Module

I did go in a define AcqParamModel using:

qmlRegisterType<AcqParamModel>("XMUIQml", 1, 0, "AcqParamModel");

So I can get the enum values that way. But that means I cannot write generic code that works with multiple model types. I have to know which model type my code is accessing. This is really cumbersome. Maybe just setting properties on selection would be more generic.

kshegunov

My knowledge of QML is almost non-existent, but can't you register the enum of AcqParamModel with qmlRegisterUncreatableType()? I think this is why it was invented.

PS: Or registering the enum of the class directly?

fcarney

I decided to go a different all QML route:

                       MouseArea {
                            anchors.fill: parent
                            onClicked: {
                                delegate.ListView.view.currentIndex = index
                                delegate.ListView.view.currentName = name
                                delegate.ListView.view.currentModuleName = modulename
                            }
                        }

This mousearea is inside my view delegate. I just have to make sure there is a selection. The other route via the data method just has too much boilerplate.

fcarney

Apparently you can access currentItem of the model. So if you set properties on that delegate then you can access them through the currentItem interface.

GrecKo

I've create a small lib related to your problem : https://github.com/oKcerG/QmlModelHelper

You can query the roleNames of an arbitrary model with model.ModelHelper.roles as a map property or model.ModelHelper.roleForName("roleName") returning an int.
There's also some convenience data method like model.ModelHelper.data(row, "roleName").