Solved Update Listview elements on signal in qml

[nikhil30]

Hi,
I am using listview in order to display vertical list of elements. I want to update the listview elements (Text property) on the reception of signal in qml.
How could i update the listview elements'property using c++ functions on signal received...?

Below is the snippet of my code:

    Component {
        id: my_delegate

            Item {
                id: alarm_1
                width: 680
                height: 190

                Rectangle {
                    x:0
                    y:188
                    width:(680-10)
                    height:4
                    smooth: false
                    border.width: 2
                    border.color: "#303030"
                }

                Text {
                    id: alarm_primary_zone
                    x: 20
                    y: 20
                    width: 300
                    height: 26
                    color: "#e0e0e0"
                    text: alarm.getAlarmPrimZone(index)
                    font.family: "Honeywell Sans"
                    wrapMode: Text.WordWrap
                    verticalAlignment: Text.AlignTop
                    font.pixelSize: 22
                    horizontalAlignment: Text.AlignLeft
                }

                Text {
                    id: alarm_1_primary_zone_label
                    x: 20
                    y: 54
                    width: 300
                    height: 26
                    color: "#e0e0e0"
                    text:alarm.getAlarmZoneLabel(index)
                    font.family: "Honeywell Sans"
                    wrapMode: Text.WordWrap
                    verticalAlignment: Text.AlignTop
                    font.pixelSize: 22
                    horizontalAlignment: Text.AlignLeft
                }

                Text {
                    id: alarm_1_device_label
                    x: 20
                    y: 88
                    width: 300
                    height: 26
                    color: "#e0e0e0"
                    text: alarm.getAlarmPointInfo(index)
                    font.family: "Honeywell Sans"
                    wrapMode: Text.WordWrap
                    verticalAlignment: Text.AlignTop
                    font.pixelSize: 22
                    horizontalAlignment: Text.AlignLeft
                }

                Text {
                    id: alarm_1_date_time_stamp
                    x: 450
                    y: 88
                    width: 211
                    height: 26
                    color: "#ffffff"
                    text: alarm.getAlarmTimestamp(index)
                    font.family: "Honeywell Sans"
                    wrapMode: Text.WordWrap
                    verticalAlignment: Text.AlignTop
                    font.pixelSize: 22
                    horizontalAlignment: Text.AlignLeft
                }
}

    ListView {
        id:view
        x:120
        y:80
        width:680
        height:320
        contentWidth: 680
        delegate: my_delegate
        model: alarm.getDisplayEvtCount(); //no of elements in list
        boundsBehavior: Flickable.StopAtBounds
        flickableDirection:Flickable.VerticalFlick
        orientation: Qt.Vertical
        spacing: 0
        interactive: true
        cacheBuffer: 190
    }
Connections {
         onDisplayListUpdate {
                  //  want to update listview elements here 
                  //  e.g alarm_primary_zone.text = "New Text"  or call c++ function alarm.getAlarmPrimZone(index)
         }
}

[sierdzio]

You're doing it backwards. You should update the model used by ListView, then the delegates will update automatically.

Currently you're just using an integer model, so easiest way to trigger an update is to do:

view.model = 0
view.model = alarm.getDisplayEvtCount();

But a much better and future-proof solution is to construct a custom model based on QAbstractItemModel class. Define the roles you need and use them in your delegates in QML. This way Qt will handle view updates completely automatically.

There are also other ways to do this, see: link and link.

[sierdzio]

You're doing it backwards. You should update the model used by ListView, then the delegates will update automatically.

Currently you're just using an integer model, so easiest way to trigger an update is to do:

view.model = 0
view.model = alarm.getDisplayEvtCount();

But a much better and future-proof solution is to construct a custom model based on QAbstractItemModel class. Define the roles you need and use them in your delegates in QML. This way Qt will handle view updates completely automatically.

There are also other ways to do this, see: link and link.

[nikhil30]

Thanks for the reply.

I will also try to implement custom model based on QAbstractItemModel class as suggested.