matplotlib Qt widget plotting

plot by matplotlib widget from Qt Designer

from sys import argv
from PyQt4 import QtGui, QtCore


# Import the interface class
import main_window

#matplotlibwidget is inherit from matplotlibwidget in site-packages, which pointed by matplotlibplugin.py of Qt Desiner python plugin -- matplotplugin
#several options of this matplotlibwidget implementation as matplotlibwidget_withbar.py or mplwidget.py could apply as your demands
from matplotlibwidget import *
from numpy import linspace


class PlotViewer(QtGui.QMainWindow, main_window.Ui_MainWindow):
    """ The second parent must be 'Ui_<obj. name of main widget class>'.
        If confusing, simply open up ImageViewer.py and get the class
        name used. I'd named mine as mainWindow, hence Ui_mainWindow. """

    def __init__(self, parent=None):
        super(PlotViewer, self).__init__(parent)
        # This is because Python does not automatically
        # call the parent's constructor.
        self.setupUi(self)
        # Pass this "self" for building widgets and
        # keeping a reference.
        self.mplwidget = MatplotlibWidget(self,title='Example',
                                              xlabel='Linear scale',
                                              ylabel='Log scale',
                                              hold=True, yscale='log')
        self.mplwidget.setFocus()
        self.setCentralWidget(self.mplwidget)
        self.plot(self.mplwidget.axes)

    def plot(self, axes):
        x = linspace(-10, 10)
        axes.plot(x, x**2)
        axes.plot(x, x**3)

    def main(self):
        self.show()

if __name__=='__main__':
    app = QtGui.QApplication(argv)
    plotViewer = PlotViewer()
    plotViewer.main()
    app.exec_()