manage QML Repeater from python

_{Disclaimer: The code you provide is useless since it does not show any attempt to solve your problem, besides that there are undefined elements that I will not take as a basis for my answer, and it is a shame because you always learn more by correcting errors.}

If you want to handle the information that the Repeater uses from Python then you must use a model. The Repeater supports 3 types of models:

• A number,
• A list or
• An object that inherits from QAbstractItemModel.

In this case the first does not provide important information since it only indicates the number of elements so it will not show it since it is a trivial example.

In the case of the list the logic is to create a Q_PROPERTY of type "QVariantList" (in PyQt5 list is enough) and that has an associated signal that is emitted every time the list changes so that the view is notified and updates the painting.

import os.path
import sys

from PySide2.QtCore import Property, QObject, QDateTime, QTimer, QUrl, Signal
from PySide2.QtGui import QGuiApplication
from PySide2.QtQml import QQmlApplicationEngine


CURRENT_DIRECTORY = os.path.dirname(os.path.realpath(__file__))


class Controller(QObject):
    modelChanged = Signal()

    def __init__(self, parent=None):
        super().__init__(parent)

        self._model = ["Text1", "Text2", "Text3"]

    @Property("QVariantList", notify=modelChanged)
    def model(self):
        return self._model

    def update_model(self, l):
        self._model = l[:]
        self.modelChanged.emit()


if __name__ == "__main__":
    app = QGuiApplication(sys.argv)

    controller = Controller()

    engine = QQmlApplicationEngine()
    engine.rootContext().setContextProperty("controller", controller)
    filename = os.path.join(CURRENT_DIRECTORY, "main.qml")
    engine.load(QUrl.fromLocalFile(filename))

    if not engine.rootObjects():
        sys.exit(-1)

    def on_timeout():
        dt = QDateTime.currentDateTime()
        l = [dt.addSecs(i).toString() for i in range(3)]
        controller.update_model(l)

    timer = QTimer(timeout=on_timeout, interval=1000)
    timer.start()

    sys.exit(app.exec_())

import QtQuick 2.15
import QtQuick.Window 2.15
import QtQuick.Controls 2.15

Window{
    width: 640
    height: 480
    visible: true

    Column {
        Repeater {
            model: controller.model
            Button {
                text: model.modelData
            }
        }
    }
}

In the case of QAbstractItemModel the logic is to create a QProperty of type QObject and make it constant since the model itself does not change but the information it manages. And on the QML side, the property must be accessed using the associated role, for example in the case of QStringListModel the role is "display":

import os.path
import sys

from PySide2.QtCore import Property, QDateTime, QObject, QStringListModel, QTimer, QUrl
from PySide2.QtGui import QGuiApplication
from PySide2.QtQml import QQmlApplicationEngine


CURRENT_DIRECTORY = os.path.dirname(os.path.realpath(__file__))


class Controller(QObject):
    def __init__(self, parent=None):
        super().__init__(parent)

        self._model = QStringListModel()

        self.model.setStringList(["Text1", "Text2", "Text3"])

    def get_model(self):
        return self._model

    model = Property(QObject, fget=get_model, constant=True)


if __name__ == "__main__":
    app = QGuiApplication(sys.argv)

    controller = Controller()

    engine = QQmlApplicationEngine()
    engine.rootContext().setContextProperty("controller", controller)
    filename = os.path.join(CURRENT_DIRECTORY, "main.qml")
    engine.load(QUrl.fromLocalFile(filename))

    if not engine.rootObjects():
        sys.exit(-1)

    def on_timeout():
        dt = QDateTime.currentDateTime()
        l = [dt.addSecs(i).toString() for i in range(3)]
        controller.model.setStringList(l)

    timer = QTimer(timeout=on_timeout, interval=1000)
    timer.start()

    sys.exit(app.exec_())

import QtQuick 2.15
import QtQuick.Window 2.15
import QtQuick.Controls 2.15

Window{
    width: 640
    height: 480
    visible: true

    Column {
        Repeater {
            model: controller.model
            Button {
                text: model.display
            }
        }
    }
}

You can also create a custom model but you have to declare a role associated with the data, a trivial example is to use the QStandardItemModel class.

import os.path
import sys

from PySide2.QtCore import (
    Property,
    QDateTime,
    QObject,
    Qt,
    QTimer,
    QUrl,
)
from PySide2.QtGui import QGuiApplication, QStandardItem, QStandardItemModel
from PySide2.QtQml import QQmlApplicationEngine


CURRENT_DIRECTORY = os.path.dirname(os.path.realpath(__file__))

TEXT_ROLE = Qt.UserRole + 1000
DATA_ROLE = TEXT_ROLE + 1


class Controller(QObject):
    def __init__(self, parent=None):
        super().__init__(parent)

        self._model = QStandardItemModel()
        self.model.setItemRoleNames({TEXT_ROLE: b"text", DATA_ROLE: b"data"})
        for i in range(3):
            item = QStandardItem()
            item.setData("Text{}".format(i), TEXT_ROLE)
            item.setData(i, DATA_ROLE)
            self.model.appendRow(item)

    def get_model(self):
        return self._model

    model = Property(QObject, fget=get_model, constant=True)


if __name__ == "__main__":
    app = QGuiApplication(sys.argv)

    controller = Controller()

    engine = QQmlApplicationEngine()
    engine.rootContext().setContextProperty("controller", controller)
    filename = os.path.join(CURRENT_DIRECTORY, "main.qml")
    engine.load(QUrl.fromLocalFile(filename))

    if not engine.rootObjects():
        sys.exit(-1)

    def on_timeout():
        dt = QDateTime.currentDateTime()
        for i in range(controller.model.rowCount()):
            item = controller.model.item(i)
            item.setData(dt.addSecs(i).toString(), TEXT_ROLE)
            item.setData(dt.addSecs(i), DATA_ROLE)

    timer = QTimer(timeout=on_timeout, interval=1000)
    timer.start()

    sys.exit(app.exec_())

import QtQuick 2.15
import QtQuick.Window 2.15
import QtQuick.Controls 2.15

Window{
    width: 640
    height: 480
    visible: true

    Column {
        Repeater {
            model: controller.model
            Button {
                text: model.text
                onClicked: console.log(model.data)
            }
        }
    }
}

You could also create a class that inherits from QAbstractListModel and overrides the data, setData, roleNames, rowCount methods.