[FIXED] PyQt5 updating nested QWidgets

Issue

I am trying to code my first PyQt project and want to update both the textfield on the right and the plot on the left when I choose the New Pattern option from the menu bar. I think that the actions from the menu bar trigger correctly but the triggered functions themselves do not update the Canvas Figure or Label correctly (so in the end nothing happens when I click the create). I tried different versions of self.update() and do not really find my way around to the solution in the pyqt documentation, as I only find solutions to updating a normal QWidget but my structure is nested, so maybe there is just one tiny mistake that I am not quite getting...

I would appreciate any help or feedback to the style of my code as well since I am not too familiar with Python or PyQt itself.

import sys
import numpy as np
from screeninfo import get_monitors

from PyQt5.QtWidgets import QApplication, QMainWindow, QMenuBar, QAction, QHBoxLayout, QVBoxLayout, QWidget, QLabel
from PyQt5.QtGui import QPalette, QColor

import matplotlib.pyplot as plt
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg
from matplotlib.figure import Figure

# grid class
class Grid(FigureCanvasQTAgg):
    def __init__(self, parent = None, width = 5, height = 5, dpi = 120):
        fig = Figure(figsize=(width, height), dpi=dpi)
        self.ax = fig.add_subplot()
        self.ax.set_ylim(-8.75, 8.75)
        self.ax.set_xlim(-8.75, 8.75)
        ticks = list(range(-8, 9))
        self.ax.xaxis.set_ticks(ticks)
        self.ax.yaxis.set_ticks(ticks)
        self.ax.grid(visible = True)
        self.ax.set_axisbelow(True)
        self.ax.tick_params(axis='both', which='both', length=0, labeltop=True, labelright=True)
        self.ax.set_aspect('equal')
        for spine in self.ax.spines.values():
            spine.set_visible(False)
        self.title_font_ = {'fontsize': 16, 'fontweight': "normal", 'color': "black", 
                      'verticalalignment': "center", 'horizontalalignment': "center"}
        self.ax.set_title("Grid Title", fontdict = self.title_font_, pad = 35)
        self.circles = []
        super(Grid, self).__init__(fig)
    
    def createPattern(self, dots = 8, unified = True):
        self.dots = dots
        self.unified = unified
        # change title
        self.ax.set_title("Add Pattern", fontdict = self.title_font_, pad = 35)
        
        x = list(range(-8, -8+dots))
        y = [8.01]*dots
        
        if self.unified:
            coord = np.array(list(map(list, zip(x, y))))
            for i in range(self.pairs):
                circ = self.ax.add_patch(plt.Circle((coord[i,0], coord[i,1]), 0.35, color="royalblue"))
                self.circles.append(circ)
        else:
            xw = list(range(1, 1+dots))
            coord_blue = np.array(list(map(list, zip(x, y))))
            coord_pink = np.array(list(map(list, zip(xw, y))))
            for i in range(dots):
                circ = self.ax.add_patch(plt.Circle((coord_pink[i,0], coord_pink[i,1]), 0.35, color="deeppink"))
                self.circles.append(circ)
            for i in range(dots):
                circ = self.ax.add_patch(plt.Circle((coord_blue[i,0], coord_blue[i,1]), 0.35, color="deepskyblue"))
                self.circles.append(circ)

class Side(QWidget):
    def __init__(self, color):
        super(Side, self).__init__()
        
        # background color
        self.setAutoFillBackground(True)
        palette = self.palette()
        palette.setColor(QPalette.Window, QColor(color))
        self.setPalette(palette)
        
        # add layout and text
        self.layout = QVBoxLayout()
        self.label = QLabel("Welcome to My first program")
        self.layout.addWidget(self.label)
        self.setLayout(self.layout)
        
    def createPattern(self):
        self.label = QLabel("Now we will create a pattern")
        #self.update()  ??
        #super(Side, self).update()  ??

class MainWindow(QMainWindow):
    
    def __init__(self, parent = None):
        super().__init__(parent)
        screen = get_monitors()[0]
        self.setGeometry(int(screen.width*0.125), int(screen.height*0.125), 
                         int(screen.width*0.75), int(screen.height*0.75))
        self.setWindowTitle("My Program")
        self._createActions()
        self._createMenuBar()
        
        # a figure instance to plot on
        self.grid = Grid(width=8, height=8, dpi=140)
        # a side panel
        self.side = Side('white')
        
        self.centralwidget = QWidget()
        self.setCentralWidget(self.centralwidget)
        self.layout = QHBoxLayout(self.centralwidget)
        self.layout.addWidget(self.grid, 55)
        self.layout.addWidget(self.side, 45)
        
    def _createActions(self):
        self.newPatternAction = QAction("&New Pattern", self)
        
    def _createMenuBar(self):
        menuBar = QMenuBar(self)
        self.setMenuBar(menuBar)

        patternMenu = menuBar.addMenu("&Pattern")
        patternMenu.addAction(self.newPatternAction)
        
    def _connectActions(self):
        self.newPatternAction.triggered.connect(self.newPattern)
    
    def newPattern(self):
        # Logic for creating a new file goes here...
        self.grid.createPattern()
        self.side.createPattern()

def window():
    app = QApplication(sys.argv)
    win = MainWindow()
    win.show()
    sys.exit(app.exec_())

if __name__ == "__main__":
    app = QApplication(sys.argv)
    app.setQuitOnLastWindowClosed(True)    
    win = MainWindow()
    win.show()
    sys.exit(app.exec_())

Solution

The solution is rather embarrassing - I did not properly connect the Menu Action.

import sys
import numpy as np
from screeninfo import get_monitors

from PyQt5.QtWidgets import QApplication, QMainWindow, QMenuBar, QAction, QHBoxLayout, QVBoxLayout, QWidget, QLabel
from PyQt5.QtGui import QPalette, QColor

import matplotlib.pyplot as plt
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg
from matplotlib.figure import Figure

# grid class
class Grid(FigureCanvasQTAgg):
    def __init__(self, parent = None, width = 5, height = 5, dpi = 120):
        fig = Figure(figsize=(width, height), dpi=dpi)
        self.ax = fig.add_subplot()
        self.ax.set_ylim(-8.75, 8.75)
        self.ax.set_xlim(-8.75, 8.75)
        ticks = list(range(-8, 9))
        self.ax.xaxis.set_ticks(ticks)
        self.ax.yaxis.set_ticks(ticks)
        self.ax.grid(visible = True)
        self.ax.set_axisbelow(True)
        self.ax.tick_params(axis='both', which='both', length=0, labeltop=True, labelright=True)
        self.ax.set_aspect('equal')
        for spine in self.ax.spines.values():
            spine.set_visible(False)
        self.title_font_ = {'fontsize': 16, 'fontweight': "normal", 'color': "black", 
                      'verticalalignment': "center", 'horizontalalignment': "center"}
        self.ax.set_title("Grid Title", fontdict = self.title_font_, pad = 35)
        self.circles = []
        super(Grid, self).__init__(fig)
    
    def createPattern(self, dots = 8, unified = True):
        self.dots = dots
        self.unified = unified
        # change title
        self.ax.set_title("Add Pattern", fontdict = self.title_font_, pad = 35)
        
        x = list(range(-8, -8+dots))
        y = [8.01]*dots
        
        if self.unified:
            coord = np.array(list(map(list, zip(x, y))))
            for i in range(self.pairs):
                circ = self.ax.add_patch(plt.Circle((coord[i,0], coord[i,1]), 0.35, color="royalblue"))
                self.circles.append(circ)
        else:
            xw = list(range(1, 1+dots))
            coord_blue = np.array(list(map(list, zip(x, y))))
            coord_pink = np.array(list(map(list, zip(xw, y))))
            for i in range(dots):
                circ = self.ax.add_patch(plt.Circle((coord_pink[i,0], coord_pink[i,1]), 0.35, color="deeppink"))
                self.circles.append(circ)
            for i in range(dots):
                circ = self.ax.add_patch(plt.Circle((coord_blue[i,0], coord_blue[i,1]), 0.35, color="deepskyblue"))
                self.circles.append(circ)
        # THIS IS NEW TO UPDATE THE PLOT
        self.draw()

class Side(QWidget):
    def __init__(self, color):
        super(Side, self).__init__()
        
        # background color
        self.setAutoFillBackground(True)
        palette = self.palette()
        palette.setColor(QPalette.Window, QColor(color))
        self.setPalette(palette)
        
        # add layout and text
        self.layout = QVBoxLayout()
        self.label = QLabel("Welcome to My first program")
        self.layout.addWidget(self.label)
        self.setLayout(self.layout)
        
    def createPattern(self):
        # THIS IS NEW - THANK YOU MUSICAMENTE
        self.label.setText("Now we will create a pattern")

class MainWindow(QMainWindow):
    
    def __init__(self, parent = None):
        super().__init__(parent)
        screen = get_monitors()[0]
        self.setGeometry(int(screen.width*0.125), int(screen.height*0.125), 
                         int(screen.width*0.75), int(screen.height*0.75))
        self.setWindowTitle("My Program")
        self._createActions()
        self._createMenuBar()
        # THIS IS NEW TO PROPERLY CONNECT THE MENU ACTION
        self._connectActions()
        
        # a figure instance to plot on
        self.grid = Grid(width=8, height=8, dpi=140)
        # a side panel
        self.side = Side('white')
        
        self.centralwidget = QWidget()
        self.setCentralWidget(self.centralwidget)
        self.layout = QHBoxLayout(self.centralwidget)
        self.layout.addWidget(self.grid, 55)
        self.layout.addWidget(self.side, 45)
        
    def _createActions(self):
        self.newPatternAction = QAction("&New Pattern", self)
        
    def _createMenuBar(self):
        menuBar = QMenuBar(self)
        self.setMenuBar(menuBar)

        patternMenu = menuBar.addMenu("&Pattern")
        patternMenu.addAction(self.newPatternAction)
        
    def _connectActions(self):
        self.newPatternAction.triggered.connect(self.newPattern)
    
    def newPattern(self):
        # Logic for creating a new file goes here...
        self.grid.createPattern()
        self.side.createPattern()

def window():
    app = QApplication(sys.argv)
    win = MainWindow()
    win.show()
    sys.exit(app.exec_())

if __name__ == "__main__":
    app = QApplication(sys.argv)
    app.setQuitOnLastWindowClosed(True)    
    win = MainWindow()
    win.show()
    sys.exit(app.exec_())

Answered By - Galvin Hoang