关于pyqt5的一些小白的问题

MSDN_tang 2018-04-11 12:19:19

如下代码所示，我想在一个Dialog的Qwidget里绘制一个矩形，但在第48行发送信号调用DrawRec的时候并没有绘制出图形，但是把DrawRec放在paintEvent里就能绘制出来，难道Qwidget只能在paintEvent里绘制图形？还是因为我没能正确调用呢？

import sys

from PyQt5.QtCore import pyqtSlot, pyqtSignal

from PyQt5.QtWidgets import QApplication, QDialog，QWidget, QVBoxLayout

from PyQt5.QtGui import QPainter, QColor, QBrush, QPen, QPalette





class myWidget(QWidget):

    def __init__(self):

        super().__init__()

        self.setBackgroundRole(QPalette.Midlight)

        self.setAutoFillBackground(True)

    

    def paintEvent(self, e):

        # self.DrawRec(10, 10, 50, 50)

        pass

    

    @pyqtSlot(int, int, int, int)       # 定义槽函数

    def DrawRec(self, x1, y1, x2, y2):

        qp = QPainter()

        qp.begin(self)

        col = QColor(0, 0, 0)

        col.setNamedColor('#d4d4d4')

        qp.setPen(col)

        qp.setBrush(QColor(200, 0, 0))

        qp.drawRect(x1, y1, x2, y2)

        qp.end()





class Dialog(QDialog):



    _signal = pyqtSignal(int, int, int, int)    # 定义信号

    

    def __init__(self, parent=None):

        

        super(Dialog, self).__init__(parent)

        self.setObjectName("Dialog")

        self.resize(400, 300)

        self.setSizeGripEnabled(True)

        

        wigglyWidget = myWidget()

        layout = QVBoxLayout()

        layout.addWidget(wigglyWidget)

        self.setLayout(layout)

        

        

        self._signal.connect(wigglyWidget.DrawRec)      # connect

        self._signal.emit(20, 20, 50, 50)        # 信号发送





if __name__ == "__main__":

    app = QApplication(sys.argv)

    dlg = Dialog()

    dlg.show()

    sys.exit(app.exec_())