Unable to import 'matplotlib.backends.backend_qt6agg' in PyQt6 application

Question

Question about error when using PyQt6 and Matplotlib

Goal:

I am developing a PyQt6 application that uses Matplotlib for graphing. However, I encountered an error when running the program.

Description of the error:

When I run program, I encountered in this error:

Traceback (most recent call last):
  File "d:\programforpyqt6\Program\program.py", line 4, in <module>
    from matplotlib.backends.backend_qt6agg import FigureCanvasQTAgg as FigureCanvas
ModuleNotFoundError: No module named 'matplotlib.backends.backend_qt6agg'

This is my Python code:

from PyQt6.QtWidgets import QApplication, QMainWindow, QVBoxLayout, QWidget, QPushButton
import sys
from matplotlib.backends.backend_qt6agg import FigureCanvasQTAgg as FigureCanvas
import matplotlib.pyplot as plt
from matplotlib.figure import Figure
import platform
import psutil


class HardwareMonitorApp(QMainWindow):
    def __init__(self):
        super().__init__()

        self.central_widget = QWidget(self)
        self.setCentralWidget(self.central_widget)

        self.layout = QVBoxLayout(self.central_widget)

        self.cpu_button = QPushButton('Show CPU Usage', self)
        self.cpu_button.clicked.connect(self.show_cpu_usage)
        self.layout.addWidget(self.cpu_button)

        self.memory_button = QPushButton('Show Memory Usage', self)
        self.memory_button.clicked.connect(self.show_memory_usage)
        self.layout.addWidget(self.memory_button)

        self.setWindowTitle('Hardware Monitor App')

    def show_cpu_usage(self):
        x = list(range(1, 11))
        y = psutil.cpu_percent(interval=1, percpu=True)

        self.plot_graph(x, y, 'CPU Usage', 'Core', 'Usage (%)')

    def show_memory_usage(self):
        virtual_memory = psutil.virtual_memory()
        swap_memory = psutil.swap_memory()

        labels = ['Used', 'Available', 'Total']
        sizes = [virtual_memory.used, virtual_memory.available, virtual_memory.total]

        self.plot_pie_chart(labels, sizes, 'Memory Usage')

    def plot_graph(self, x, y, title, xlabel, ylabel):
        figure = Figure(figsize=(6, 4), tight_layout=True)
        plot = figure.add_subplot(1, 1, 1)
        plot.plot(x, y, marker='o')
        plot.set_title(title)
        plot.set_xlabel(xlabel)
        plot.set_ylabel(ylabel)

        canvas = FigureCanvas(figure)
        self.layout.addWidget(canvas)

    def plot_pie_chart(self, labels, sizes, title):
        figure, ax = plt.subplots()
        ax.pie(sizes, labels=labels, autopct='%1.1f%%', startangle=90)
        ax.axis('equal')  # Equal aspect ratio ensures that pie is drawn as a circle.
        ax.set_title(title)

        canvas = FigureCanvas(figure)
        self.layout.addWidget(canvas)


def main():
    app = QApplication(sys.argv)
    main_win = HardwareMonitorApp()
    main_win.show()
    sys.exit(app.exec())


if __name__ == '__main__':
    main()

Additional information:

• Version of Python: 3.12.1
• Operating System: Windows 10
• PyQt6 version: 6.6.1
• Matplotlib version: 3.8.2
• PyQt6 install method: pip install PyQt6
• Matplotlib install method: pip install matplotlib
• Virtual environment: I'm not using any virtual environment.
• I am working on: a PyQt6 application that involves using matplotlib for plotting.

Steps taken:

• Check version of PyQt6 by using this command on Command Prompt: pip show PyQt6
• Reinstall matplotlib library by using this command on Command Prompt: pip uninstall matplotlib and pip install matplotlib

My question for this error:

1. Are there any compatibility issues between PyQt6 (version 6.6.1) and matplotlib (version 3.8.2)?
2. Is there a different import statement I should be using for PyQt6 and matplotlib compatibility?
3. Are there any known issues or workarounds for this problem?