Python PyQt5：如何使用信号&x2B；用于传输paintEvent参数的插槽？

关于这个问题，我指的是来自

上面的代码显示了如何在当前小部件上绘制一个覆盖图，效果很好。但是我想将参数转移到overlay类中，并使用这些变量触发overlay类中的

paintEvent

我修改代码如下

# -*- coding:utf-8 -*-

from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *


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

        palette = QPalette(self.palette())
        palette.setColor(palette.Background, Qt.transparent)

        self.setPalette(palette)

    @pyqtSlot(int)
    def getValue(self, a):  # variable is received.
        self.a = a
        print(self.a)
        self.update()

    def paintEvent(self, event):
        painter = QPainter()
        painter.begin(self)
        painter.setRenderHint(QPainter.Antialiasing)
        painter.fillRect(event.rect(), QBrush(QColor(255, 255, 255, 127)))
        painter.drawLine(self.width() / 8, self.height() / 8, 7 * self.width() / 8, 7 * self.height() / 8)
        painter.drawLine(self.width() / 8, 7 * self.height() / 8, 7 * self.width() / 8, self.height() / 8)
        painter.drawLine(self.a , self.a+50, self.a +10, self.a + 100) #Here I want to draw the line using parameter.
        painter.setPen(QPen(Qt.NoPen))


class windowOverlay(QWidget):
    signal = pyqtSignal(int)

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

        self.editor = QTextEdit()
        self.editor.setPlainText("OVERLAY" * 100)

        self.button = QPushButton("Toggle Overlay")

        self.verticalLayout = QVBoxLayout(self)
        self.verticalLayout.addWidget(self.editor)
        self.verticalLayout.addWidget(self.button)

        self.overlay = overlay(self.editor)
        self.overlay.hide()

        self.button.clicked.connect(self.switch_and_send_signal)

    def switch_and_send_signal(self):
        if self.overlay.isVisible():
            self.overlay.setVisible(False)
        else:
            self.overlay.setVisible(True)

        self.obj = overlay()
        a = 100
        self.signal.connect(self.obj.getValue)
        self.signal.emit(a)
        self.signal.disconnect(self.obj.getValue)

    def resizeEvent(self, event):
        self.overlay.resize(event.size())
        event.accept()


if __name__ == "__main__":
    import sys

    app = QApplication(sys.argv)
    main = windowOverlay()
    main.show()
    sys.exit(app.exec_())

问题： 参数似乎已传输，但未更新

paintEvent

。参数未到达

paintEvent

。我做错了什么

---

谢谢你的帮助

问题的原因是您正在创建一个未连接的覆盖对象，您必须使用下面显示的相同对象：

class windowOverlay(QWidget):
    signal = pyqtSignal(int)
    def __init__(self, parent=None):
        super(windowOverlay, self).__init__(parent)

        self.editor = QTextEdit()
        self.editor.setPlainText("OVERLAY" * 100)

        self.button = QPushButton("Toggle Overlay")

        self.verticalLayout = QVBoxLayout(self)
        self.verticalLayout.addWidget(self.editor)
        self.verticalLayout.addWidget(self.button)

        self.overlay = overlay(self.editor)
        self.overlay.hide()
        self.signal.connect(self.overlay.getValue)

        self.button.clicked.connect(self.switch_and_send_signal)

    def switch_and_send_signal(self):
        self.overlay.setVisible(not self.overlay.isVisible())
        a = 100
        self.signal.emit(a)

    def resizeEvent(self, event):
        self.overlay.resize(event.size())
        event.accept()