如何发送和解压缩从python到qml的元组列表？

Question

我需要在python端生成一个元组列表，并将其发送到qml并打印出来，但是当我尝试在qml端打印此列表时，它会打印：

qml: [QVariant(PyQt_PyObject),QVariant(PyQt_PyObject),QVariant(PyQt_PyObject),QVariant(PyQt_PyObject),QVariant(PyQt_PyObject),QVariant(PyQt_PyObject),QVariant(PyQt_PyObject),QVariant(PyQt_PyObject),QVariant(PyQt_PyObject),QVariant(PyQt_PyObject)]

如何解压缩这些值？

UPD

最小示例：

main.py

from PyQt5.QtGui import QGuiApplication
from PyQt5.QtQml import QQmlApplicationEngine
from PyQt5.QtCore import QObject, pyqtSignal, pyqtSlot


class Plot(QObject):
    def __init__(self):
        QObject.__init__(self)

    updCanv = pyqtSignal(list, arguments=['upd'])


    @pyqtSlot()
    def upd(self):
        points = [(1, 2), (3, 4)]

        self.updCanv.emit(points)

if __name__ == "__main__":
    import sys
    sys.argv += ['--style', 'material']
    app = QGuiApplication(sys.argv)
    engine = QQmlApplicationEngine()
    plot = Plot()
    engine.rootContext().setContextProperty("plot", plot)
    engine.load("main.qml")
    engine.quit.connect(app.quit)
    sys.exit(app.exec_())

main.qml

import QtQuick 2.0
import QtQuick.Controls 2.1
import QtQuick.Layouts 1.2

ApplicationWindow {
        visible: true

        Button {
            text: qsTr("Get points")
            onClicked: plot.upd()
        }

        Connections {
            target: plot
            onUpdCanv: print(upd)
        }
}

Answer 1

并非所有类型都在QML中映射，例如python的类型列表被映射为QML的列表类型，但是在元组的情况下则不是，因此解决方案是使用某些等效类型或创建一些新类型，在这种情况下，由于元组有2个元素，因此您可以轻松使用QPointF()。

class Plot(QObject):
    updCanv = pyqtSignal(list, arguments=['upd'])
    @pyqtSlot()
    def upd(self):
        points = [(1, 2), (3, 4)]
        p = [QPointF(*v) for v in points]
        self.updCanv.emit(p)

输出：

qml: [QPointF(1, 2),QPointF(3, 4)]