I can't import FigureCanvas

hernancrespo89

Hi everyone
I created a simple GUI using PyQt5 and matplotlib and it works without problem. But i see this error in line which i import FigureCanvas

from matplotlib.backends.backend_qt5agg import FigureCanvas

Cannot find reference 'FigureCanvas' in 'backend_qt5agg.py'

Here is my code:
main.py

# ------------------------------------------------------
# ---------------------- main.py -----------------------
# ------------------------------------------------------
from PyQt5.QtWidgets import *
from PyQt5.uic import loadUi

from matplotlib.backends.backend_qt5agg import (NavigationToolbar2QT as NavigationToolbar)

import numpy as np
import random


class MatplotlibWidget(QMainWindow):

    def __init__(self):
        QMainWindow.__init__(self)

        loadUi("qt_designer.ui", self)

        self.setWindowTitle("PyQt5 & Matplotlib Example GUI")

        self.pushButton.clicked.connect(self.update_graph)

        self.addToolBar(NavigationToolbar(self.MplWidget.canvas, self))

    def update_graph(self):
        fs = 500
        f = random.randint(1, 100)
        ts = 1 / fs
        length_of_signal = 100
        t = np.linspace(0, 1, length_of_signal)

        cosinus_signal = np.cos(2 * np.pi * f * t)
        sinus_signal = np.sin(2 * np.pi * f * t)

        self.MplWidget.canvas.axes.clear()
        self.MplWidget.canvas.axes.plot(t, cosinus_signal)
        self.MplWidget.canvas.axes.plot(t, sinus_signal)
        self.MplWidget.canvas.axes.legend(('cosinus', 'sinus'), loc='upper right')
        self.MplWidget.canvas.axes.set_title('Cosinus - Sinus Signal')
        self.MplWidget.canvas.draw()


app = QApplication([])
window = MatplotlibWidget()
window.show()
app.exec_()

mplwidget.py

# ------------------------------------------------------
# -------------------- mplwidget.py --------------------
# ------------------------------------------------------
from PyQt5.QtWidgets import *

from matplotlib.backends.backend_qt5agg import FigureCanvas

from matplotlib.figure import Figure


class MplWidget(QWidget):

    def __init__(self, parent=None):
        QWidget.__init__(self, parent)

        self.canvas = FigureCanvas(Figure())

        vertical_layout = QVBoxLayout()
        vertical_layout.addWidget(self.canvas)

        self.canvas.axes = self.canvas.figure.add_subplot(111)
        self.setLayout(vertical_layout)

jsulm

@hernancrespo89 Did you check whether FigureCanvas in fact is in backend_qt5agg.py?

hernancrespo89

yes i did