Question

I have a Python program to plot a simple graph in using a custom matplotlib widget.
My code is as follows:

import sys
from GUI import *
import random
import matplotlib.pyplot as plt

class GUIForm(QtGui.QDialog):

    def __init__(self, parent=None):
        QtGui.QWidget.__init__(self,parent)
        self.ui = Ui_Dialog()
        self.ui.setupUi(self)

        QtCore.QObject.connect(self.ui.pushButton,
                               QtCore.SIGNAL('clicked()'), self.PlotFunc)

    def PlotFunc(self):
        randValList = random.sample(range(0, 10), 10)
        print(randValList)
        self.ui.PlotWidget.canvas.ax.clear()
        self.ui.PlotWidget.canvas.ax.plot(randValList)

    def callFunc(self):
        myapp.PlotFunc()


if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    myapp = GUIForm()
    myapp.show()
    sys.exit(app.exec_())

When I run the program I can see the GUI but when I click the button the plot does not show the line. The empty plot is visible.
However if I dO

def __init__(self, parent=None):
            QtGui.QWidget.__init__(self,parent)
            self.ui = Ui_Dialog()
            self.ui.setupUi(self)

            QtCore.QObject.connect(self.ui.pushButton,
                                   QtCore.SIGNAL('clicked()'), self.PlotFunc)
            self.ui.PlotWidget.canvas.ax.plot(randValList)

or

if __name__ == "__main__":
        app = QtGui.QApplication(sys.argv)
        myapp = GUIForm()
        myapp.show()
        self.PlotFunc()
        sys.exit(app.exec_())

the program draws the graph.
So I’m guessing it has to do with sys.exit(app.exec_()) but do not know how to fix this.
Any help is appreciated.

Thank you.

Answer 1

By any chance, does it work if you add this line at the end of PlotFunc?

self.ui.PlotWidget.canvas.draw()