Vues en liste

Listviews can help you display objects from a model in an attractive way. To use a list view, you have to keep track of three things:

1. Le modèle contenant les données que vous souhaitez afficher dans votre vue en liste.
2. Le délégué, définissant comment chaque élément du modèle sera affiché.
3. L'affichage en liste lui-même, qui affichera les informations du modèle en fonction du délégué.

Si vous souhaitez obtenir des précisions, la documentation de Qt contient une page d'informations sur ce sujet.

Création d'une Listview basique

Une vue en liste possède deux propriétés essentielles auxquelles nous devons prêter attention :

• model, which accepts the data or the id of the object that holds the data
• delegate, which accepts the component we will use to display the data in the model

import QtQuick 2.15
import QtQuick.Controls 2.15 as Controls
import QtQuick.Layouts 1.15
import org.kde.kirigami 2.20 as Kirigami

Kirigami.Page {

    ListView {
        id: myList

        // La fourniture d'un nombre pour la propriété du modèle générera ce nombre d'entrées de
        // données à partir de 0.
        model: 200

        delegate: Kirigami.BasicListItem {
            label: "Item " + modelData
        }
    }
}

In cases where your model data only contain a single piece of data, like in the example above, you can just grab the data in the model by referencing modelData.

Une note sur les délégués : si votre modèle contient des objets avec des données dans des propriétés nommées, le nom de ces propriétés sera automatiquement exposé à votre délégué et vous aurez seulement besoin d'utiliser ces noms dans votre délégué.

ListModel {
    id: myModel
    ListElement { type: "Item"; number: 0 }
    ListElement { type: "Item"; number: 1 }
    ListElement { type: "Item"; number: 2 }
    ListElement { type: "Item"; number: 3 }
}

ListView {
    id: myList

    model: myModel

    delegate: Kirigami.BasicListItem {
        label: type + " " + number
    }
}

Kirigami offers a number of components that have been designed specifically for use in list views, such as Kirigami.BasicListItem , Kirigami.CheckableListItem and Kirigami.SwipeListItem , all of which build upon Kirigami.AbstractListItem . There are also Kirigami.CheckDelegate , Kirigami.RadioDelegate , and Kirigami.SwitchDelegate , which are designed to take advantage of those specific controls.

However, you are not limited to using these components and you can choose whichever ones you wish. This may require some tweaking of your layout.

Messages de remplacement

In some cases, you might want to use a list view that is empty until the user does something. In these situations, using a Kirigami.PlaceholderMessage can be an attractive way of telling your user that the list is empty and that they can do something about it.

You will generally want to place a placeholder message in the center of the ListView and you will likely not want it to span the entire width of the ListView. You will obviously also want it to be hidden once the ListView's model becomes populated with data. Thankfully, ListViews have a property named count that makes doing this quite easy.

You might also want to add a helpful action to your placeholder message. This can be done by attaching an action to the PlaceholderMessage.helpfulAction property.

ListView {
    id: myList

    model: ListModel { id: myModel }

    delegate: Kirigami.BasicListItem {
        label: text
    }

    Kirigami.PlaceholderMessage {
        anchors.centerIn: parent
        width: parent.width - Kirigami.Units.largeSpacing * 4
        visible: myList.count === 0
        text: "Add something to me!"

        helpfulAction: Kirigami.Action {
            icon.name: "list-add"
            text: "Add"
            onTriggered: myModel.append({"text": "Hello!!"})
        }
    }
}