Я не могу сгенерировать график, используя MatplotLib для построения графиков в приложении PyQt5

Question

Я хотел знать, как работает построение Matplotlib в настольном приложении PyQT5.Я пробовал несколько способов, чтобы график был построен, но без помощи.Я использовал функцию печати, чтобы я мог хотя бы знать, что график построен.Он печатается в виде графика, но график не отображается.Нужна помощь здесь.Ниже мой код

'''
Created on Oct 8, 2018

@author: kjohn
'''
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QApplication, QWidget, QInputDialog, QLineEdit, QFileDialog, QMessageBox, QMainWindow, QVBoxLayout
from PyQt5.QtGui import QIcon
import os
import csv
import matplotlib
from matplotlib import figure
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt5agg import NavigationToolbar2QT as NavigationToolbar


class MatplotlibFigure(QWidget):
    def __init__(self):
        super().__init__()
        self.figure = matplotlib.figure.Figure()
        self.canvas = FigureCanvas(self.figure)
        self.toolbar = NavigationToolbar(self.canvas, self)

    def plot(self):
        self.figure.clf()
        ax = self.figure.add_subplot(111)
        x = [i for i in range(100)]
        y = [i**0.5 for i in x]
        ax.plot(x, y, 'g*-')
        self.canvas.draw_idle()
        print('PLOTTED')


class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(1001, 651)
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        Form.setFont(font)
        Form.setMouseTracking(True)
        Form.setWindowTitle("Data Analytical Tool Kit")
        self.pushButton = QtWidgets.QPushButton(Form)
        self.pushButton.setGeometry(QtCore.QRect(440, 70, 121, 25))
        self.pushButton.clicked.connect(self.inputfileselector)
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.pushButton.setFont(font)
        self.pushButton.setMouseTracking(True)
        self.pushButton.setObjectName("pushButton")
        self.comboBox = QtWidgets.QComboBox(Form)
        self.comboBox.setGeometry(QtCore.QRect(670, 70, 241, 30))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        self.comboBox.setFont(font)
        self.comboBox.setMouseTracking(True)
        self.comboBox.setObjectName("comboBox")
        self.comboBox.addItem('Site Classifier')
        self.comboBox.addItem('Account Classifier')
        self.comboBox.addItem('Meter Classifier')
        self.comboBox.addItem('EMS - Audit Engine')
        self.comboBox.addItem('Budget Forecaster')
        self.lineEdit = QtWidgets.QLineEdit(Form)
        self.lineEdit.setGeometry(QtCore.QRect(20, 70, 411, 25))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setPointSize(10)
        self.lineEdit.setFont(font)
        self.lineEdit.setAutoFillBackground(True)
        self.lineEdit.setInputMethodHints(QtCore.Qt.ImhHiddenText)
        self.lineEdit.setText("")
        self.lineEdit.setObjectName("lineEdit")
        self.lineEdit.setReadOnly(True)
        self.label = QtWidgets.QLabel(Form)
        self.label.setGeometry(QtCore.QRect(21, 51, 91, 16))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.label.setFont(font)
        self.label.setObjectName("label")
        self.label_2 = QtWidgets.QLabel(Form)
        self.label_2.setGeometry(QtCore.QRect(671, 52, 108, 16))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.label_2.setFont(font)
        self.label_2.setObjectName("label_2")
        self.pushButton_2 = QtWidgets.QPushButton(Form)
        self.pushButton_2.setGeometry(QtCore.QRect(669, 161, 121, 31))
        font = QtGui.QFont()
        font.setBold(True)
        font.setWeight(75)
        self.pushButton_2.setFont(font)
        self.pushButton_2.setObjectName("pushButton_2")
        self.pushButton_2.clicked.connect(self.plot_data)
        self.pushButton_3 = QtWidgets.QPushButton(Form)
        self.pushButton_3.setGeometry(QtCore.QRect(792, 161, 121, 31))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.pushButton_3.setFont(font)
        self.pushButton_3.setObjectName("pushButton_3")
        self.pushButton_4 = QtWidgets.QPushButton(Form)
        self.pushButton_4.setGeometry(QtCore.QRect(440, 117, 121, 25))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.pushButton_4.setFont(font)
        self.pushButton_4.setMouseTracking(True)
        self.pushButton_4.setObjectName("pushButton_4")
        self.pushButton_4.clicked.connect(self.outputfolderselector)
        self.lineEdit_2 = QtWidgets.QLineEdit(Form)
        self.lineEdit_2.setGeometry(QtCore.QRect(20, 117, 411, 25))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setPointSize(10)
        self.lineEdit_2.setReadOnly(True)
        self.lineEdit_2.setFont(font)
        self.lineEdit_2.setAutoFillBackground(True)
        self.lineEdit_2.setInputMethodHints(QtCore.Qt.ImhHiddenText)
        self.lineEdit_2.setText("")
        self.lineEdit_2.setObjectName("lineEdit_2")
        self.label_3 = QtWidgets.QLabel(Form)
        self.label_3.setGeometry(QtCore.QRect(21, 97, 121, 16))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.label_3.setFont(font)
        self.label_3.setObjectName("label_3")
        self.textEdit = QtWidgets.QTextEdit(Form)
        self.textEdit.setGeometry(QtCore.QRect(20, 210, 411, 421))
        self.textEdit.setObjectName("textEdit")
        self.progressBar = QtWidgets.QProgressBar(Form)
        self.progressBar.setGeometry(QtCore.QRect(670, 116, 275, 31))
        self.progressBar.setProperty("value", 24)
        self.progressBar.setObjectName("progressBar")
        self.pushButton_5 = QtWidgets.QPushButton(Form)
        self.pushButton_5.setGeometry(QtCore.QRect(440, 166, 121, 25))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.pushButton_5.setFont(font)
        self.pushButton_5.setMouseTracking(True)
        self.pushButton_5.setObjectName("pushButton_5")
        self.pushButton_5.clicked.connect(self.resultfolderselector)
        self.lineEdit_3 = QtWidgets.QLineEdit(Form)
        self.lineEdit_3.setGeometry(QtCore.QRect(20, 166, 411, 25))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setPointSize(7)
        font.setPointSize(10)
        self.lineEdit_3.setReadOnly(True)
        self.lineEdit_3.setFont(font)
        self.lineEdit_3.setAutoFillBackground(True)
        self.lineEdit_3.setInputMethodHints(QtCore.Qt.ImhHiddenText)
        self.lineEdit_3.setText("")
        self.lineEdit_3.setObjectName("lineEdit_3")
        self.label_4 = QtWidgets.QLabel(Form)
        self.label_4.setGeometry(QtCore.QRect(22, 146, 121, 16))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.label_4.setFont(font)
        self.label_4.setObjectName("label_4")
        self.retranslateUi(Form)
        QtCore.QMetaObject.connectSlotsByName(Form)

        self.figure = matplotlib.figure.Figure()
        self.canvas = FigureCanvas(self.figure)
        self.toolbar = NavigationToolbar(self.canvas, Form)
        self.verticalLayoutWidget = QtWidgets.QWidget(Form)
        self.verticalLayoutWidget.setGeometry(QtCore.QRect(440, 210, 541, 421))
        self.verticalLayoutWidget.setObjectName("verticalLayoutWidget")
        self.verticalLayout = QtWidgets.QVBoxLayout(self.verticalLayoutWidget)
        self.verticalLayout.setContentsMargins(0, 0, 0, 0)
        self.verticalLayout.setObjectName("verticalLayout")
        self.verticalLayout.addWidget(self.canvas)
        self.verticalLayout.addWidget(self.toolbar)
        self.figure = MatplotlibFigure()

    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))
        self.pushButton.setText(_translate("Form", "Browse File"))
        self.label.setText(_translate("Form", "Input File Upload"))
        self.label_2.setText(_translate("Form", "Select Classifier Type"))
        self.pushButton_2.setText(_translate("Form", "Submit"))
        self.pushButton_3.setText(_translate("Form", "Cancel"))
        self.pushButton_4.setText(_translate("Form", "Select Folder"))
        self.label_3.setText(_translate("Form", "Output Folder for Logs"))
        self.pushButton_5.setText(_translate("Form", "Select Folder"))
        self.label_4.setText(_translate("Form", "Result Folder"))
        Form.setWindowIcon(QtGui.QIcon('icon.png'))
        Form.setWindowTitle('Data Analysis Tool Kit')
        Form.setGeometry(180,50,1001,651)
        Form.setFixedSize(1001,651)
        Form.setWindowFlags( QtCore.Qt.CustomizeWindowHint | QtCore.Qt.MSWindowsFixedSizeDialogHint |QtCore.Qt.WindowCloseButtonHint | QtCore.Qt.WindowMinimizeButtonHint )


    def inputfileselector(self):
        path = os.path.join(os.path.join(os.environ['USERPROFILE']), 'Desktop')
        filename = QtWidgets.QFileDialog.getOpenFileName(None, 'Select the Input File', path,'All Files(*.csv*)')
        if filename is filename:
            self.lineEdit.setText(str(filename))            
        else:
            self.lineEdit.setText("No file was selected.")
            QtWidgets.QMessageBox.critical(Form, "Alert", "No file was selected.", QtWidgets.QMessageBox.Close)

    def outputfolderselector(self):
        path = os.path.join(os.path.join(os.environ['USERPROFILE']), 'Desktop')
        startingDir = path
        directory = QtWidgets.QFileDialog.getExistingDirectory(None, 'Open working directory', startingDir, QtWidgets.QFileDialog.ShowDirsOnly)
        if directory:
            self.lineEdit_2.setText(directory)
        else:
            self.lineEdit_2.setText('')
            QtWidgets.QMessageBox.critical(Form, "Alert", "No folder selected.", QtWidgets.QMessageBox.Close)

    def resultfolderselector(self):
        path = os.path.join(os.path.join(os.environ['USERPROFILE']), 'Desktop')
        startingDir = path
        directory = QtWidgets.QFileDialog.getExistingDirectory(None, 'Open working directory', startingDir, QtWidgets.QFileDialog.ShowDirsOnly)
        if directory:
            self.lineEdit_3.setText(directory)
        else:
            self.lineEdit_3.setText('')
            QtWidgets.QMessageBox.critical(Form, "Alert", "No folder selected.", QtWidgets.QMessageBox.Close)

    def plot_data(self):
        self.figure.plot()
        self.canvas.setParent(self)

if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    Form = QtWidgets.QWidget()
    ui = Ui_Form()
    ui.setupUi(Form)
    Form.show()
    sys.exit(app.exec_())

Answer 1

Сначала вы создали class MatplotlibFigure для matlabplot, в то же время вы определяете функцию matlab в class Ui_Form, это ошибка.Чтобы решить вашу проблему,

Нам нужно определить две функции внутри class MatplotlibFigure, первую функцию initializewidget(), которая определяет виджет холста и рамку рисунка для matlabplot с QGridLayout местами и упорядочивает их.Затем вторая функция plot() рисует входные данные.

    def initializewidget(self):

        gridlayout = QGridLayout()
        self.setLayout(gridlayout)

        self.figure = plt.figure(figsize=(5,5))
        self.canvas = FigureCanvas(self.figure)
        self.toolbar = NavigationToolbar(self.canvas,self)
        gridlayout.addWidget(self.canvas,1,0,1,2)
        gridlayout.addWidget(self.toolbar,0,0,1,2)

И, наконец, виджет Matlabplot должен быть добавлен в макет основного виджета.

        self.matplot = MatplotlibFigure()
        self.verticalLayout.addWidget(self.matplot)

Matplotlib.pyplot используется для получения более качественных графиков, и даже графики можно настраивать с использованием различных стилей.

        import matplotlib.pyplot as plt
        plt.style.use('ggplot')

Рабочий экран тока

Рабочий код

from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QApplication, QWidget, QInputDialog, QLineEdit, 
QFileDialog, QMessageBox, QMainWindow, QVBoxLayout, QGridLayout
from PyQt5.QtGui import QIcon
import os
import csv
import matplotlib
from matplotlib import figure
import matplotlib.pyplot as plt
plt.style.use('ggplot')
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt5agg import NavigationToolbar2QT as NavigationToolbar


class MatplotlibFigure(QWidget):
    def __init__(self):
        super().__init__()        
        self.initializewidget()
        self.plot()


    def initializewidget(self):

        gridlayout = QGridLayout()
        self.setLayout(gridlayout)

        self.figure = plt.figure(figsize=(5,5))
        self.canvas = FigureCanvas(self.figure)
        self.toolbar = NavigationToolbar(self.canvas,self)
        gridlayout.addWidget(self.canvas,1,0,1,2)
        gridlayout.addWidget(self.toolbar,0,0,1,2)

    def plot(self):
        ax = self.figure.add_subplot(111)
        x = [i for i in range(100)]
        y = [1*i for i in x]
        ax.plot(x, y, 'g*-')
        self.canvas.draw()



class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(1001, 651)
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        Form.setFont(font)
        Form.setMouseTracking(True)
        Form.setWindowTitle("Data Analytical Tool Kit")
        self.pushButton = QtWidgets.QPushButton(Form)
        self.pushButton.setGeometry(QtCore.QRect(440, 70, 121, 25))
        self.pushButton.clicked.connect(self.inputfileselector)
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.pushButton.setFont(font)
        self.pushButton.setMouseTracking(True)
        self.pushButton.setObjectName("pushButton")
        self.comboBox = QtWidgets.QComboBox(Form)
        self.comboBox.setGeometry(QtCore.QRect(670, 70, 241, 30))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        self.comboBox.setFont(font)
        self.comboBox.setMouseTracking(True)
        self.comboBox.setObjectName("comboBox")
        self.comboBox.addItem('Site Classifier')
        self.comboBox.addItem('Account Classifier')
        self.comboBox.addItem('Meter Classifier')
        self.comboBox.addItem('EMS - Audit Engine')
        self.comboBox.addItem('Budget Forecaster')
        self.lineEdit = QtWidgets.QLineEdit(Form)
        self.lineEdit.setGeometry(QtCore.QRect(20, 70, 411, 25))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setPointSize(10)
        self.lineEdit.setFont(font)
        self.lineEdit.setAutoFillBackground(True)
        self.lineEdit.setInputMethodHints(QtCore.Qt.ImhHiddenText)
        self.lineEdit.setText("")
        self.lineEdit.setObjectName("lineEdit")
        self.lineEdit.setReadOnly(True)
        self.label = QtWidgets.QLabel(Form)
        self.label.setGeometry(QtCore.QRect(21, 51, 91, 16))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.label.setFont(font)
        self.label.setObjectName("label")
        self.label_2 = QtWidgets.QLabel(Form)
        self.label_2.setGeometry(QtCore.QRect(671, 52, 108, 16))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.label_2.setFont(font)
        self.label_2.setObjectName("label_2")
        self.pushButton_2 = QtWidgets.QPushButton(Form)
        self.pushButton_2.setGeometry(QtCore.QRect(669, 161, 121, 31))
        font = QtGui.QFont()
        font.setBold(True)
        font.setWeight(75)
        self.pushButton_2.setFont(font)
        self.pushButton_2.setObjectName("pushButton_2")
        self.pushButton_2.clicked.connect(self.plot_data)
        self.pushButton_3 = QtWidgets.QPushButton(Form)
        self.pushButton_3.setGeometry(QtCore.QRect(792, 161, 121, 31))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.pushButton_3.setFont(font)
        self.pushButton_3.setObjectName("pushButton_3")
        self.pushButton_4 = QtWidgets.QPushButton(Form)
        self.pushButton_4.setGeometry(QtCore.QRect(440, 117, 121, 25))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.pushButton_4.setFont(font)
        self.pushButton_4.setMouseTracking(True)
        self.pushButton_4.setObjectName("pushButton_4")
        self.pushButton_4.clicked.connect(self.outputfolderselector)
        self.lineEdit_2 = QtWidgets.QLineEdit(Form)
        self.lineEdit_2.setGeometry(QtCore.QRect(20, 117, 411, 25))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setPointSize(10)
        self.lineEdit_2.setReadOnly(True)
        self.lineEdit_2.setFont(font)
        self.lineEdit_2.setAutoFillBackground(True)
        self.lineEdit_2.setInputMethodHints(QtCore.Qt.ImhHiddenText)
        self.lineEdit_2.setText("")
        self.lineEdit_2.setObjectName("lineEdit_2")
        self.label_3 = QtWidgets.QLabel(Form)
        self.label_3.setGeometry(QtCore.QRect(21, 97, 121, 16))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.label_3.setFont(font)
        self.label_3.setObjectName("label_3")
        self.textEdit = QtWidgets.QTextEdit(Form)
        self.textEdit.setGeometry(QtCore.QRect(20, 210, 411, 421))
        self.textEdit.setObjectName("textEdit")
        self.progressBar = QtWidgets.QProgressBar(Form)
        self.progressBar.setGeometry(QtCore.QRect(670, 116, 275, 31))
        self.progressBar.setProperty("value", 24)
        self.progressBar.setObjectName("progressBar")
        self.pushButton_5 = QtWidgets.QPushButton(Form)
        self.pushButton_5.setGeometry(QtCore.QRect(440, 166, 121, 25))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.pushButton_5.setFont(font)
        self.pushButton_5.setMouseTracking(True)
        self.pushButton_5.setObjectName("pushButton_5")
        self.pushButton_5.clicked.connect(self.resultfolderselector)
        self.lineEdit_3 = QtWidgets.QLineEdit(Form)
        self.lineEdit_3.setGeometry(QtCore.QRect(20, 166, 411, 25))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setPointSize(7)
        font.setPointSize(10)
        self.lineEdit_3.setReadOnly(True)
        self.lineEdit_3.setFont(font)
        self.lineEdit_3.setAutoFillBackground(True)
        self.lineEdit_3.setInputMethodHints(QtCore.Qt.ImhHiddenText)
        self.lineEdit_3.setText("")
        self.lineEdit_3.setObjectName("lineEdit_3")
        self.label_4 = QtWidgets.QLabel(Form)
        self.label_4.setGeometry(QtCore.QRect(22, 146, 121, 16))
        font = QtGui.QFont()
        font.setFamily("Segoe UI")
        font.setBold(True)
        font.setWeight(75)
        self.label_4.setFont(font)
        self.label_4.setObjectName("label_4")
        self.retranslateUi(Form)
        QtCore.QMetaObject.connectSlotsByName(Form)

        self.matplot = MatplotlibFigure()
        self.verticalLayoutWidget = QtWidgets.QWidget(Form)
        self.verticalLayoutWidget.setGeometry(QtCore.QRect(440, 210, 541, 421))
        self.verticalLayoutWidget.setObjectName("verticalLayoutWidget")
        self.verticalLayout = QtWidgets.QVBoxLayout(self.verticalLayoutWidget)
        self.verticalLayout.setContentsMargins(0, 0, 0, 0)
        self.verticalLayout.setObjectName("verticalLayout")
        # self.verticalLayout.addWidget(self.matplot)   # comment this line



    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))
        self.pushButton.setText(_translate("Form", "Browse File"))
        self.label.setText(_translate("Form", "Input File Upload"))
        self.label_2.setText(_translate("Form", "Select Classifier Type"))
        self.pushButton_2.setText(_translate("Form", "Submit"))
        self.pushButton_3.setText(_translate("Form", "Cancel"))
        self.pushButton_4.setText(_translate("Form", "Select Folder"))
        self.label_3.setText(_translate("Form", "Output Folder for Logs"))
        self.pushButton_5.setText(_translate("Form", "Select Folder"))
        self.label_4.setText(_translate("Form", "Result Folder"))
        Form.setWindowIcon(QtGui.QIcon('icon.png'))
        Form.setWindowTitle('Data Analysis Tool Kit')
        Form.setGeometry(180,50,1001,651)
        Form.setFixedSize(1001,651)
        Form.setWindowFlags( QtCore.Qt.CustomizeWindowHint | 
        QtCore.Qt.MSWindowsFixedSizeDialogHint |QtCore.Qt.WindowCloseButtonHint | 
                                              QtCore.Qt.WindowMinimizeButtonHint )


    def inputfileselector(self):
        path = os.path.join(os.path.join(os.environ['USERPROFILE']), 'Desktop')
        filename = QtWidgets.QFileDialog.getOpenFileName(None, 'Select the Input 
                                                  File', path,'All Files(*.csv*)')
        if filename is filename:
            self.lineEdit.setText(str(filename))            
        else:
            self.lineEdit.setText("No file was selected.")
            QtWidgets.QMessageBox.critical(Form, "Alert", "No file was selected.", 
                                                      QtWidgets.QMessageBox.Close)

    def outputfolderselector(self):
        path = os.path.join(os.path.join(os.environ['USERPROFILE']), 'Desktop')
        startingDir = path
        directory = QtWidgets.QFileDialog.getExistingDirectory(None, 'Open working 
          directory', startingDir, QtWidgets.QFileDialog.ShowDirsOnly)
        if directory:
            self.lineEdit_2.setText(directory)
        else:
            self.lineEdit_2.setText('')
            QtWidgets.QMessageBox.critical(Form, "Alert", "No folder selected.", 
                                                     QtWidgets.QMessageBox.Close)

    def resultfolderselector(self):
        path = os.path.join(os.path.join(os.environ['USERPROFILE']), 'Desktop')
        startingDir = path
        directory = QtWidgets.QFileDialog.getExistingDirectory(None, 'Open working 
                       directory', startingDir, QtWidgets.QFileDialog.ShowDirsOnly)
        if directory:
            self.lineEdit_3.setText(directory)
        else:
            self.lineEdit_3.setText('')
            QtWidgets.QMessageBox.critical(Form, "Alert", "No folder selected.", 
                                                     QtWidgets.QMessageBox.Close)

    def plot_data(self):
        # self.figure.plot()            # comment this line
        # self.canvas.setParent(self)   # comment this line
        self.verticalLayout.addWidget(self.matplot)  # <--- Add this line

if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    Form = QtWidgets.QWidget()
    ui = Ui_Form()
    ui.setupUi(Form)
    Form.show()
    sys.exit(app.exec_())