的Python：Matplotlib按鈕無效

Question

我有一個包含一個名爲bbutton按鈕按下時執行movetext功能驗證碼：

from pylab import * 
from matplotlib.widgets import RectangleSelector 
from matplotlib.widgets import Button 
import numpy as np 
import matplotlib.pylab as plt 


fig = plt.figure() 
ax = fig.add_subplot(111) 

delta = 0.025 
x = np.arange(-3.0, 3.0, delta) 
y = np.arange(-2.0, 2.0, delta) 
X, Y = np.meshgrid(x, y) 
Z1 = bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0) 
Z2 = bivariate_normal(X, Y, 1.5, 0.5, 1, 1) 
Z = (Z1 - Z2) * 10 

plt.contourf(X, Y, Z) 

text1=plt.text(0, 0, 'ghghg',color='black',fontsize=14) 
plt.text(1, 1, 'Calculation ',color='black',fontsize=14) 
plt.title('Average ') 

plt.xlabel('Longtitude ', fontsize=14, color='black') 
plt.ylabel('Latitude ', fontsize=14, color='black') 
plt.grid(True) 

def onselect(eclick, erelease): 
    'eclick and erelease are matplotlib events at press and release' 
    text1.set_text('Geo ') 
    text1.set_x(eclick.xdata) 
    text1.set_y(eclick.ydata) 
    plt.draw() 

def toggle_selector(event): 
    print ' Key pressed.' 
    if event.key in ['Q', 'q'] and toggle_selector.RS.active: 
     print ' RectangleSelector deactivated.' 
     toggle_selector.RS.set_active(False) 
    if event.key in ['A', 'a'] and not toggle_selector.RS.active: 
     print ' RectangleSelector activated.' 
     toggle_selector.RS.set_active(True) 

def movetext(self): 
    print 'clearing plot' 
    text1.set_x(np.random.random(1)) 
    text1.set_y(np.random.random(1)) 
    plt.draw() 


toggle_selector.RS = RectangleSelector(ax, onselect, drawtype='line') 
plt.connect('key_press_event', toggle_selector) 

buttonaxe = plt.axes([0.7, 0.05, 0.1, 0.1]) 
bbutton = Button(buttonaxe, 'movetext',color='0.85', hovercolor='0.95') 
bbutton.on_clicked(movetext) 

plt.show() 

放置在底部的按鈕工作正常。 但在下面的例子中，如果我只是把所有的代碼放在一個名爲Plotter的函數中，那麼按鈕會出現在圖中，但它不起作用。當鼠標懸停在按鈕上方時沒有變化，並且連接的功能movetext未執行。

from pylab import * 
from matplotlib.widgets import RectangleSelector 
from matplotlib.widgets import Button 
import numpy as np 
import matplotlib.pylab as plt 

fig = plt.figure() 
ax = fig.add_subplot(111) 


def Plotter(): 

    delta = 0.025 
    x = np.arange(-3.0, 3.0, delta) 
    y = np.arange(-2.0, 2.0, delta) 
    X, Y = np.meshgrid(x, y) 
    Z1 = bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0) 
    Z2 = bivariate_normal(X, Y, 1.5, 0.5, 1, 1) 
    Z = (Z1 - Z2) * 10 
    #Z1 = mlab.bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0) 
    plt.contourf(X, Y, Z) 
    text1=plt.text(0, 0, 'ghghg',color='black',fontsize=14) 
    plt.text(1, 1, 'Calculation ',color='black',fontsize=14) 
    plt.title('Average ') 

    plt.xlabel('Longtitude ', fontsize=14, color='black') 
    plt.ylabel('Latitude ', fontsize=14, color='black') 
    plt.grid(True) 

    def onselect(eclick, erelease): 
     'eclick and erelease are matplotlib events at press and release' 
     text1.set_text('Geo ') 
     text1.set_x(eclick.xdata) 
     text1.set_y(eclick.ydata) 
     plt.draw() 

    def toggle_selector(event): 
     print ' Key pressed.' 
     if event.key in ['Q', 'q'] and toggle_selector.RS.active: 
      print ' RectangleSelector deactivated.' 
      toggle_selector.RS.set_active(False) 
     if event.key in ['A', 'a'] and not toggle_selector.RS.active: 
      print ' RectangleSelector activated.' 
      toggle_selector.RS.set_active(True) 

    def movetext(self): 
     print 'clearing plot' 
     text1.set_x(np.random.random(1)) 
     text1.set_y(np.random.random(1)) 
     plt.draw() 


    toggle_selector.RS = RectangleSelector(ax, onselect, drawtype='line') 
    plt.connect('key_press_event', toggle_selector) 

    buttonaxe = plt.axes([0.7, 0.05, 0.1, 0.1]) 
    bbutton = Button(buttonaxe, 'movetext',color='0.85', hovercolor='0.95') 
    bbutton.on_clicked(movetext) 
Plotter()  
plt.show() 

有人可以解釋這種行爲嗎？我究竟做錯了什麼？

Answer 1

這是因爲bbutton是本地名稱，當Plotter()通話結束後，名bbutton走了，並沒有什麼參考Button對象，它會被垃圾收集器回收。

爲了解決這個問題，你可以創建一個虛擬參考吧，比如添加以下行的Plotter結束：

buttonaxe._button = bbutton