QML - .qml 文件中的“连接”不会触发来自 python 脚本的信号

Question

这是 main.py 脚本：

import sys, os, math
import numpy as np
from PyQt5 import *


class Tab(QFrame):
    def __init__(self):
        super().__init__()
        self.setGeometry(600, 600, 600, 600)
        self.setWindowTitle("PyQt5 Tab Widget")
        self.setWindowIcon(QIcon("../QML Files/Icons/Tab.png"))

        vbox = QVBoxLayout()
        tabWidget = QTabWidget()

        tabWidget.addTab(Example01(), "Ex1")
       

        vbox.addWidget(tabWidget)
        self.setLayout(vbox)


class GG(QObject):
    def __init__(self, parent=None):
        super().__init__(parent)
        self._polygons = []

    @pyqtSlot()
    def modify_Polygons(self) -> None:
        animation = QVariantAnimation(self)
        animation.setStartValue(0)
        animation.setEndValue(10)
        animation.valueChanged.connect(
            lambda value: GG.set_dynamic_polygons(value, self)
        )
        animation.setDuration(10 * 1000)
        animation.start(QAbstractAnimation.DeleteWhenStopped)

    polygonschanged = pyqtSignal(str)

    def get_polygons(self) -> None:
        return self._polygons

    def set_polygons(self, polygons):
        self._polygons = polygons
        self.polygonschanged.emit("Test")

    polygons = pyqtProperty(
        "QVariant", fget=get_polygons, fset=set_polygons,
        notify=polygonschanged
    )

    def set_dynamic_polygons(i, p_gg) -> None:

        numpy_arrays = np.array(
            [[[100+3*i, 100], [150, 200], [50, 300]],
             [[50, 60], [160, 20], [400, 10]]]
        )

        def set_polygons(myArray) -> []:
            polygons = []
            for ps in myArray:
                polygon = []
                # print("ps = "); print(ps)
                for p in ps:
                    # print("p = "); print(p)
                    e = QPointF(*p)
                    polygon.append(e)
                polygons.append(polygon)
            return polygons

        p_gg.polygons = set_polygons(numpy_arrays)


class Example01(QWidget):
    def __init__(self):
        super().__init__()
        vbox = QVBoxLayout(self)
        vbox.setContentsMargins(0, 0, 0, 0)
        self.gg = GG()
        GG.set_dynamic_polygons(0, self.gg)

        view = QQuickWidget()
        view.rootContext().setContextProperty("gg", self.gg)

        ROOT_DIR = os.path.realpath(os.path.dirname(sys.argv[0]))
        qml = os.path.join(ROOT_DIR, "QML Files", "Demo02.qml")
        view.setSource(QUrl.fromLocalFile(qml))
        view.setResizeMode(QQuickWidget.SizeRootObjectToView)
        vbox.addWidget(view)

if __name__ == "__main__":
    App = QApplication(sys.argv)
    tabDialog = Tab()
    tabDialog.show()
    App.exec()

这是 Demo02.qml 脚本：

import QtQuick 2.14
import QtQuick.Window 2.14
import QtGraphicalEffects 1.0
import QtQuick.Controls 2.15


Rectangle {
    id: rect

        visible: true
        anchors.fill: parent

        LinearGradient {
                anchors.fill: parent
                //setting gradient at 45 degrees
                start: Qt.point(rect.width, 0)
                end: Qt.point(0, rect.height)
                gradient: Gradient {
                    GradientStop { position: 0.0; color: "#ee9d9d" }
                    GradientStop { position: 1.0; color: "#950707" }
                }
            }
        Button{
            id: btn
            width: 100
            height: 30
            x: {parent.width - btn.width - 20}
            y: {parent.height - btn.height - 20}
            text: "Animate!"
            onClicked: {gg.modify_Polygons()}
        }

        Canvas {
            id: drawingCanvas
            anchors.fill: parent
            
            onPaint: {
                var ctx = getContext("2d")
                ctx.fillStyle = "rgb(100%,70%,30%)"
                ctx.lineWidth = 5
                ctx.strokeStyle = "blue"
                //console.log(gg)
                for(var i in gg.polygons){
                    var polygon = gg.polygons[i]
                    ctx.beginPath()

                    for(var j in polygon){
                        var p = polygon[j]
                        if(j === 0)
                            ctx.moveTo(p.x, p.y)
                        else
                            ctx.lineTo(p.x, p.y)
                    }
                    ctx.closePath()
                    ctx.fill()
                    ctx.stroke()
                }

            }
            Connections{
                 target: gg
                 function onpolygonschanged(strng){
                     console.log(strng)
                     drawingCanvas.requestPaint()}
             }
        }



    }

除了 Demo02.qml 文件末尾的 Connections 指令并没有真正调用 polygonschanged 之外，一切运行正常来自 python 的信号。 我刚刚插入了console.log("Test") 来检查是否发出信号以便被.qml 文件看到，但我没有收到任何反应。 我不得不提一下，画布最初显示了 2 个三角形，但是当我单击“激活！”时按钮画布显示相同的三角形，但不对其进行动画处理。 有人可以建议如何正确设置 .qml 文件中的“连接”吗？

Answer 1

在qml中与信号关联的函数名必须是CamelCase，即：

Connections{
    target: gg
    function onPolygonsChanged(strng){
        console.log(strng)
        drawingCanvas.requestPaint()
    }
}