使用 Kivy 的 Python 跨类函数调用

Question

我想从cpopup 类调用reflist() 函数。我不确定该怎么做。在self.dismiss() 行之后，我尝试了很多方法。

narr.reflist() 感觉它应该可以工作，但事实并非如此。我想可能是因为我需要引用类的实例而不是类本身，但我不太确定实例名称是什么以及如何引用它。

narr().reflist() 更成功一点，因为它不会出现错误。但结果出乎意料（什么也没发生）。也许它确实有效，但我只是还不了解类中的变量范围。

execfile("drawinglist.py")
    dlists = []
    dsource = []

    class cpopup(Popup):
        filechooser = ObjectProperty(None)
        def on_press_dismiss(self, *args):
            self.dismiss()
            #return False

        def load(self, path, filename):
            fdid = self.id
            bodycon = ObjectProperty(None)
            if fdid == "Narr":
                print parseNarrative(filename)
                dsource.append(filename)
                dlists.append(parseNarrative(filename))
                self.dismiss()
                narr.reflist()
            if fdid == "Dir":
                print parseFolder(filename, True)
                self.dismiss()
            if fdid == "Dl":
                print parseDrawinglist(filename)
                self.dismiss()

    class narr(BoxLayout):
        bodycon = ObjectProperty(None)
        dlists  = ObjectProperty(None)
        def loadNarr(self):
            pop = cpopup()
            pop.title="Select a file to generate Drawing List from"
            pop.id = "Narr"
            pop.filechooser.multiselect = True
            pop.open()

        def loadDir(self):
            pop = cpopup()
            pop.title="Select a Directory to load drawing list from."
            pop.id = "Dir"
            pop.filechooser.dirselect = True
            pop.open()

        def loadDl(self):
            pop = cpopup()
            pop.title="Select a drawing list (.pdfs) to generate list from"
            pop.id = "Dl"
            pop.filechooser.multiselect = True
            pop.open()

        def reflist(self):
            words = ""
            source = ""
            index = []

            for d in dlists:
                for a in d:
                    dwg = str(a)
                    if dwg not in index:
                        index.append(dwg)

            for l in dsource:
                fl = l[0]
                fl = fl.split("/")
                fl = fl[-1]
                source = source + fl +"\n"

            self.dlists.text = source
            self.bodycon.text = words

    class narrApp(App):
        def build(self):
            return narr()

    if __name__=="__main__":
        narrApp().run()

Answer 1

方法很多，看用途：

• 如果您的班级彼此相等通过App.get_running_app() 在您的第二个班级的实例中调用它，如下所示（仅限 Kivy）：

  class MyWidget(Widget):
      def __init__(self, *args, **kwargs):
          self.app = App.get_running_app()
          self.app.my_widget = self
  
      def func(self, *args):
          pass
  
  class MyAnotherWidget(Widget):
      # you'll need this piece in the class you want to
      # access func() from and you'll need App instance
      # present too
      def __init__(self, *args, **kwargs):
          self.app = App.get_running_app()
          self.app.my_widget.func()
  

• master ↔ slave classes（一个总是在上面）：

  class Slave:
      def func(self, *args):
          pass
  
  class Master:
      # creating of the slave instance is required
      def __init__(self, *args, **kwargs):
          self.slave_class = Slave()
          self.slave_class.master_class = self
          self.slave_class.func()
  

  基本上这就是App ↔ 其他所有关系的运作方式。有主要的主类，您唯一要做的就是将“从”类的附加引用添加到“主”类的已创建实例。

• 静态方法s

  class Something:
      @staticmethod
      def static_func(*args):
          pass
  
  class SomethingElse:
      def __init__(self, *args, **kwargs):
          Something.static_func()
  

  装饰器允许你像那样使用它，但是你不能访问静态方法所属的类中的任何东西（没有self，没有课堂乐趣）。您肯定已经在这种形状的某个包中遇到过它们：Package.do_something(*args)，这可能是一个静态方法。

• 类方法s

  class Something:
      def __init__(self, first=None, second=None, *args, **kwargs):
          print(first, second)
  
      @classmethod
      def class_func(cls, arg_list):
          special_Something = cls(arg_list[0], arg_list[1])
          return special_Something
  
  class SomethingElse:
      def __init__(self, *args, **kwargs):
          new_something = Something.class_func(['hi', 'there'])
  

  基本上，例如，如果您想要传递一个特殊格式来创建一个类，但该类有 不同 输入参数，您可以使用类似的 classmethod 来了解您的输入你想使用它的类。