how to automatically update Listview in qml when ListModel changed-CodePudding

I have a problem that I use ListModel to save information that I read from database. But when the ListModel updated, the ListView did not update. my code as below:

ListModel{ id: selectedTempStationlistModel }

I read my database as below and append records from database:

selectedTempStationlistModel.append({"id": idValue})

and my ListView like that :

**ListView{
    id: amr_view_three
    model: selectedTempStationlistModel
    height: 220
    width: 655
    anchors.centerIn: parent
    Layout.columnSpan: 2
    Layout.fillHeight: true
    Layout.fillWidth: true
    clip: true
    delegate: Component  {
        Item{
            width: amr_view_three.width
            height: 80
            Text {
                anchors.centerIn: parent
                text: id
                font.family:"SimSun"
                font.pointSize: 16
            }
        }
    }
}**

My target only need to show id from databse to listview. each time I add one record in database, I checked my ModelList that already changed, however, the ListView does not update new data of the model. Please help me. Thanks

CodePudding user response：

Your view will not update automatically when you update the model, you need to emit the corresponding signals in order for your view to update, generally you would have a update function in your model that looks like something like this:

def update(self, ...){
    self.layoutAboutToBeChanged.emit()
    # update your model
    self.layoutChanged.emit()
}

You need to emit layouAboutToBeChanged before you touch any model data, and after you update emit layoutChanged

CodePudding user response：

Thank TOHO. Perhaps some cases the model can not update automatically, my case my model can update automatically. The reason is Because of my poor typo. Btw, I found something related to forceLayout() in some cases if model can not update automatically. Thank you for your time so much