matplotlib.widgets 按钮在类中不起作用

Question

我以滑块小部件为例，并尝试将其插入到一个类中。滑块可以正常工作，但由于某种原因，当该方法位于类中时，Button 和 RadioButtons 没有反应：

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.widgets import Slider, Button, RadioButtons
class test(object):
    def __init__(self):

        fig, ax = plt.subplots()
        plt.subplots_adjust(left=0.25, bottom=0.25)
        t = np.arange(0.0, 1.0, 0.001)
        a0 = 5
        f0 = 3
        s = a0*np.sin(2*np.pi*f0*t)
        l, = plt.plot(t, s, lw=2, color='red')
        plt.axis([0, 1, -10, 10])

        axcolor = 'lightgoldenrodyellow'
        axfreq = plt.axes([0.25, 0.1, 0.65, 0.03], facecolor=axcolor)
        axamp = plt.axes([0.25, 0.15, 0.65, 0.03], facecolor=axcolor)

        sfreq = Slider(axfreq, 'Freq', 0.1, 30.0, valinit=f0)
        samp = Slider(axamp, 'Amp', 0.1, 10.0, valinit=a0)


        def update(val):
            amp = samp.val
            freq = sfreq.val
            l.set_ydata(amp*np.sin(2*np.pi*freq*t))
            fig.canvas.draw_idle()
        sfreq.on_changed(update)
        samp.on_changed(update)

        resetax = plt.axes([0.8, 0.025, 0.1, 0.04])
        button = Button(resetax, 'Reset', color=axcolor, hovercolor='0.975')

        def reset(event):
            sfreq.reset()
            samp.reset()
        button.on_clicked(reset)

        rax = plt.axes([0.025, 0.5, 0.15, 0.15], facecolor=axcolor)
        radio = RadioButtons(rax, ('red', 'blue', 'green'), active=0)


        def colorfunc(label):
            l.set_color(label)
            fig.canvas.draw_idle()
        radio.on_clicked(colorfunc)

        plt.show()

如果我现在尝试使用这个类，Button 和 RadioButton 会被冻结……有人遇到过这个吗？

Answer 1

您失去了对类构造函数中静态定义的小部件和方法的引用。文档说“为了保证小部件保持响应性而不是垃圾收集，用户应该维护对对象的引用。”
通常的方法是使用类属性 ( self.)。这意味着您需要按如下方式更改代码：

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.widgets import Slider, Button, RadioButtons
class test(object):
    def __init__(self):

        self.fig, ax = plt.subplots()
        plt.subplots_adjust(left=0.25, bottom=0.25)
        self.t = np.arange(0.0, 1.0, 0.001)
        a0 = 5
        f0 = 3
        s = a0*np.sin(2*np.pi*f0*self.t)
        self.l, = plt.plot(self.t, s, lw=2, color='red')
        plt.axis([0, 1, -10, 10])

        axcolor = 'lightgoldenrodyellow'
        axfreq = plt.axes([0.25, 0.1, 0.65, 0.03], facecolor=axcolor)
        axamp = plt.axes([0.25, 0.15, 0.65, 0.03], facecolor=axcolor)

        self.sfreq = Slider(axfreq, 'Freq', 0.1, 30.0, valinit=f0)
        self.samp = Slider(axamp, 'Amp', 0.1, 10.0, valinit=a0)
        self.sfreq.on_changed(self.update)
        self.samp.on_changed(self.update)

        resetax = plt.axes([0.8, 0.025, 0.1, 0.04])
        self.button = Button(resetax, 'Reset', color=axcolor, hovercolor='0.975')
        self.button.on_clicked(self.reset)

        rax = plt.axes([0.025, 0.5, 0.15, 0.15], facecolor=axcolor)
        self.radio = RadioButtons(rax, ('red', 'blue', 'green'), active=0)
        self.radio.on_clicked(self.colorfunc)

        plt.show()

    def update(self,val):
        amp = self.samp.val
        freq = self.sfreq.val
        self.l.set_ydata(amp*np.sin(2*np.pi*freq*self.t))
        self.fig.canvas.draw_idle()

    def reset(self, event):
        self.sfreq.reset()
        self.samp.reset()

    def colorfunc(self, label):
        self.l.set_color(label)
        self.fig.canvas.draw_idle()

test()