在条件中断开 PyQt 信号

Question

我在PyQt 中遇到了一些鼠标事件问题。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)

问题是我无法使用以下方法断开鼠标事件的信号：

self.figure_canvas.mpl_disconnect(cid)

什么都没有发生，我每次点击都会画一条线。鼠标事件仍处于连接状态。

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处？您可能需要将 存储在变量中才能正确断开连接：

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)