Python tkinter 上 matplotlib 如何更新？

Question

I use matplotlib in tkinter. I want to update the matplotlib status to a new status as function, how can i solve it?

import matplotlib.pyplot as plt
import numpy as np
from matplotlib.backends.backend_tkagg import (FigureCanvasTkAgg, NavigationToolbar2Tk)

window = tk.Tk()

def change():
    ss =  np.random.randint(100)
    ss1 =  np.random.randint(100)
    ss2 =  np.random.randint(100)
    x = ['Col A', 'Col B', 'Col C']
    y = [ss,ss1,ss2]
    fig = plt.figure(figsize=(4, 5))
    plt.bar(x=x, height=y)

    
    plt.xticks(x, rotation=90)
    canvas = FigureCanvasTkAgg(fig, master=window)
    canvas.draw()
    
btn = tk.Label(window, text='A simple plot')
btn.grid(row=0, column=0, padx=20, pady=10)

x = ['Col A', 'Col B', 'Col C']
y = [50, 20, 80]

fig = plt.figure(figsize=(4, 5))
plt.bar(x=x, height=y)


plt.xticks(x, rotation=90)


canvas = FigureCanvasTkAgg(fig, master=window)
canvas.draw()
canvas.get_tk_widget().grid(row=1, column=0, ipadx=40, ipady=20)

toolbarFrame = tk.Frame(master=window)
toolbarFrame.grid(row=2,column=0)
toolbar = NavigationToolbar2Tk(canvas, toolbarFrame)
button = tk.Button(text='change',command = change)
button.grid(row= 3,column =0)

window.mainloop()

output When this code is executed, when the button is pressed, the graph screen does not change, and when the program ends, the graphs are executed.

Answer 1

You don't need to create new figure, just update current figure:

def change():
    ss =  np.random.randint(100)
    ss1 =  np.random.randint(100)
    ss2 =  np.random.randint(100)
    x = ['Col A', 'Col B', 'Col C']
    y = [ss,ss1,ss2]
    plt.clf()  # clear current figure
    plt.bar(x=x, height=y)  # plot the graph
    plt.xticks(x, rotation=90)
    canvas.draw()  # refresh plot