使用matlibplot在单独的函数中创建子图

Question

我是python的新手并且学习绳索。我正在尝试使用pyQT来构建GUI，并希望能够有一个按钮，在轴上显示图形，然后是另一个按钮，在另一个轴上加载图像。我正在使用subplot。这是我尝试从搜索中获取的尝试，但它会继续打开第二个数字并为此绘制。

import sys
from PyQt4 import QtGui, QtCore

from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt4agg import NavigationToolbar2QTAgg as NavigationToolbar
import matplotlib.pyplot as plt
import os
import matplotlib.cm as cm

import random

class Window(QtGui.QDialog):
    def __init__(self, parent=None):
        super(Window, self).__init__(parent)

        # a figure instance to plot on
        self.figure = plt.figure()

        # this is the Canvas Widget that displays the `figure`
        # it takes the `figure` instance as a parameter to __init__
        self.canvas = FigureCanvas(self.figure)

        # this is the Navigation widget
        # it takes the Canvas widget and a parent
        self.toolbar = NavigationToolbar(self.canvas, self)

        # Just some button connected to `plot` method
        self.button = QtGui.QPushButton('Plot')
        self.button.clicked.connect(self.plot)
        self.button2 = QtGui.QPushButton('Open Image')
        self.button2.clicked.connect(self.OpenImage)
        self.quitButton = QtGui.QPushButton("Exit")
        #self.quitButton.clicked.connect(self.Quit)
        self.quitButton.clicked.connect(QtCore.QCoreApplication.instance().quit)
        self.cancelButton = QtGui.QPushButton("Cancel")
        self.comboBox = QtGui.QComboBox()
        self.comboBox.addItem("Item 1")
        self.comboBox.addItem("Item 2")
        self.comboBox.addItem("Item 3")
        self.txt1= QtGui.QTextEdit('Open Image')


        # set the layout
        #layout = QtGui.QVBoxLayout()
        layout = QtGui.QGridLayout()
        layout.addWidget(self.toolbar,0,0,1,5)  #spans 1 row, 5 columns
        layout.addWidget(self.canvas,1,0)
        layout.addWidget(self.button,0,1)
        layout.addWidget(self.button2,0,2)
        layout.addWidget(self.quitButton,2,1)
        layout.addWidget(self.cancelButton,2,2)
        layout.addWidget(self.comboBox,3,2)
        layout.addWidget(self.txt1,2,3)
        layout.setSpacing(10)
        self.setLayout(layout)


    def plot(self):
        ''' plot some random stuff '''
        # random data
        data = [random.random() for i in range(10)]

        # create some axes
        ax = self.figure.add_subplot(231)
        ax1 = self.figure.add_subplot(232)



        # discards the old graph
        ax.hold(False)

        # plot data
        ax.plot(data, '*-')
        plt.grid(b=True, which='both', color='0.65',linestyle='-')

        # refresh canvas
        #self.canvas.draw()

        #Add 2nd Graph
        ax1 = self.figure.add_subplot(232)
        ax1.hold(False)

        # plot data
        data = [random.random() for i in range(10)]
        ax1.plot(data, 'r*-')
        plt.grid(b=True, which='both', color='0.65',linestyle='-')

        # refresh canvas
        self.canvas.draw()

    def OpenImage(self):

        #Create some axes
        ax2 = self.figure.add_subplot(233)
        ax3 = self.figure.add_subplot(234)
        ''' Load Image from File '''        
        #os.chdir('c:\')      
        M=plt.imread('c:\Image01.tif')
  #      ax2 = self.figure.add_subplot(233)
        ax2.hold(False)
        plt.imshow(M,cmap='gray')
        plt.xticks([]), plt.yticks([])  # to hide tick values on X and Y axis


    def Quit(self):
       #return app.exec()
       sys.exit(app.exec_())

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)

    main = Window()
    main.show()

    sys.exit(app.exec_())