在条件中断开PyQt信号

Question

我在PyQt中遇到了一些鼠标事件的麻烦。这是代码：

class A(QMainWindow): 

    var = None 

    def __init__(self): 
    QMainWindow.__init__(self) 
    #Here I draw a matplotlib figure 

    self.figure_canvas = FigureCanvas(Figure()) 
    layout.addWidget(self.figure_canvas, 10) 
    self.axes = self.figure_canvas.figure.add_subplot(211) 

    #I created a toolbar for the figure and I added a QPushButton 

    self.btn_selection_tool = QPushButton() 
    self.navigation_toolbar.addWidget(self.btn_selection_tool) 
    self.connect(self.btn_selection_tool, SIGNAL("clicked()"), self.B) 

    def B(self): 
    if self.var == 1: 
     cid = self.figure_canvas.mpl_connect("press_button_event", self.C) 

    def C(self, event): 
    x = xdata.event 
    #I draw a line every time I click in the canvas 

    def D(self): 
    #Here I tried to call this method and disconnect the signal 
    self.figure_canvas.mpl_disconnect(cid) 

的问题是，我无法通过断开鼠标事件的信号：

self.figure_canvas.mpl_disconnect(cid)

什么也没有发生，我把画线每点击我做。鼠标事件仍然连接。

如何断开信号？也许使用另一个QPushButton？

Answer 1

您是否将连接存储在某个地方？您可能需要存储在一个变量正常断开：

class A(QMainWindow): 

    def __init__(self): 
     QMainWindow.__init__(self) 

     self.cid = None 

    def B(self): 
     if self.var == 1: 
      self.cid = self.figure_canvas.mpl_connect("press_button_event", self.C) 

    def D(self): 
     if self.cid is not None: 
      self.figure_canvas.mpl_disconnect(self.cid)