Python继承/多态性

Question

我在玩弄这个Python库：

Read The Docs

PopUpDialog

有一个名为PopUpDialog的对象，它的基类是Frame类型

帧对象的字段之一是可以滚动=True

当我实例化弹出对话框时，我希望该字段为假，这样就不会出现滚动条

我试图创建一个名为so的新类

class PopUpDialogNoScroll(PopUpDialog):
    super(PopUpdDialogNoScroll, self).__init__(screen,...

及

class PopUpDialogNoScroll(Frame):
    super(PopUpdDialogNoScroll, self).__init__(screen,...

但是，我所有的尝试都导致了一个错误，如“给定7个参数，预期2个”

有人能告诉我如何派生类并设置父类和/或祖父母类的字段吗

谢谢，祝你身体健康

编辑 多亏了awarrier 99，我走了这么远，但是滚动条仍然可见。这里我有一些演示代码

from asciimatics.widgets import Frame, ListBox, Layout, Divider, Text, TextBox, Widget, Button, Label, DropdownList, PopUpDialog, CheckBox, RadioButtons, PopupMenu
from asciimatics.scene import Scene
from asciimatics.screen import Screen
from asciimatics.exceptions import ResizeScreenError, NextScene, StopApplication, InvalidFields


class PopUpDialogNoScroll(PopUpDialog):
    def __init__(self, *args, **kwargs):
        super(PopUpDialogNoScroll, self).__init__(*args, **kwargs)
        self.can_scroll = False
        self.has_border = False


class DemoView(Frame):
    def __init__(self, screen):
        super(DemoView, self).__init__(screen,
                                          11,
                                          48,
                                          data=None,
                                          on_load=None,
                                          has_border=True,
                                          hover_focus=True,
                                          name=None,
                                          title="Welcome",
                                          x=None,
                                          y=None,
                                          has_shadow=False,
                                          reduce_cpu=False,
                                          is_modal=False,
                                          can_scroll=False)


        body = Layout([1], fill_frame=True)
        self.add_layout(body)
        button = Button("Click me", self.clicked, label=None)
        body.add_widget(button, 0)


    def clicked(self):
      self._scene.add_effect(
          PopUpDialogNoScroll(self.screen, "1..\n2..\n3..\n4..\n5..  ", ["OK"], on_close=self.done, has_shadow=False, theme='info'))

    def done(self):
        pass


last_scene = None

def demo(screen, scene):
  scenes = [
    Scene([DemoView(screen)], duration=-1, clear=True, name="demo"),
  ]

  screen.play(scenes, stop_on_resize=False, unhandled_input=None, start_scene=scene, repeat=True, allow_int=True)

Screen.wrapper(demo, catch_interrupt=True, arguments=[last_scene])

Answer 1

首先，对super的任何调用都应该在类自己的__init__函数的第一行中进行。因此，您的类应该有自己的__init__函数。然后，要将所有想要的参数传递给原始类，可以提供两个参数来合并继承类将具有的所有参数：*args和**kwargs。然后，可以在__init__函数中将can_scroll字段显式设置为False，如下所示：

class PopUpDialogNoScroll(PopUpDialog):
    def __init__(self, *args, **kwargs):
        super(PopUpDialogNoScroll, self).__init__(*args, **kwargs)
        self.can_scroll = False

通过使用*args和**kwargs，可以传入原始PopUpDialog类所期望的任何参数，而无需显式重写它们，并且可以将它们提供给super类

编辑： 将代码迁移到Python3时，可以将super调用更改为以下内容，这是Python3中的新语法：super().__init(*args, **kwargs)。请注意，唯一的区别是不必显式指定类名和self引用


编辑2： 查看here提供的源代码，我能够通过复制他们在PopUpDialog类中使用的任何代码，然后从源代码更改这一行来创建PopUpDialogNoScroll类：

super(PopUpDialog, self).__init__(screen, height, width, self._data, has_shadow=has_shadow, is_modal=True)

致：

super(PopUpDialogNoScroll, self).__init__(screen, height, width, self._data, has_shadow=has_shadow, is_modal=True, can_scroll=False)

虽然不是最优雅的解决方案，但它确实有效

from asciimatics.widgets import Frame, ListBox, Layout, Divider, Text, TextBox, Widget, Button, Label, DropdownList, PopUpDialog, CheckBox, RadioButtons, PopupMenu
from asciimatics.scene import Scene
from asciimatics.screen import Screen
from asciimatics.exceptions import ResizeScreenError, NextScene, StopApplication, InvalidFields
from wcwidth import wcswidth
from functools import partial

def _enforce_width(text, width, unicode_aware=True):
    """
    Enforce a displayed piece of text to be a certain number of cells wide.  This takes into
    account double-width characters used in CJK languages.
    :param text: The text to be truncated
    :param width: The screen cell width to enforce
    :return: The resulting truncated text
    """
    # Double-width strings cannot be more than twice the string length, so no need to try
    # expensive truncation if this upper bound isn't an issue.
    if (2 * len(text) < width) or (len(text) < width and not unicode_aware):
        return text

    # Can still optimize performance if we are not handling unicode characters.
    if unicode_aware:
        size = 0
        for i, c in enumerate(str(text)):
            w = wcwidth(c) if ord(c) >= 256 else 1
            if size + w > width:
                return text[0:i]
            size += w
    elif len(text) + 1 > width:
        return text[0:width]
    return text

def _split_text(text, width, height, unicode_aware=True):
    """
    Split text to required dimensions.
    This will first try to split the text into multiple lines, then put a "..." on the last
    3 characters of the last line if this still doesn't fit.
    :param text: The text to split.
    :param width: The maximum width for any line.
    :param height: The maximum height for the resulting text.
    :return: A list of strings of the broken up text.
    """
    # At a high level, just try to split on whitespace for the best results.
    tokens = text.split(" ")
    result = []
    current_line = ""
    string_len = wcswidth if unicode_aware else len
    for token in tokens:
        for i, line_token in enumerate(token.split("\n")):
            if string_len(current_line + line_token) > width or i > 0:
                # Don't bother inserting completely blank lines - which should only happen on the very first
                # line (as the rest will inject whitespace/newlines)
                if len(current_line) > 0:
                    result.append(current_line.rstrip())
                current_line = line_token + " "
            else:
                current_line += line_token + " "

    # At this point we've either split nicely or have a hugely long unbroken string (e.g. because the
    # language doesn't use whitespace.  Either way, break this last line up as best we can.
    current_line = current_line.rstrip()
    while string_len(current_line) > 0:
        new_line = _enforce_width(current_line, width, unicode_aware)
        result.append(new_line)
        current_line = current_line[len(new_line):]

    # Check for a height overrun and truncate.
    if len(result) > height:
        result = result[:height]
        result[height - 1] = result[height - 1][:width - 3] + "..."

    # Very small columns could be shorter than individual words - truncate
    # each line if necessary.
    for i, line in enumerate(result):
        if len(line) > width:
            result[i] = line[:width - 3] + "..."
    return result

class PopUpDialogNoScroll(Frame):
    """
    A fixed implementation Frame that provides a standard message box dialog.
    """

    def __init__(self, screen, text, buttons, on_close=None, has_shadow=False, theme="warning"):
        """
        :param screen: The Screen that owns this dialog.
        :param text: The message text to display.
        :param buttons: A list of button names to display. This may be an empty list.
        :param on_close: Optional function to invoke on exit.
        :param has_shadow: optional flag to specify if dialog should have a shadow when drawn.
        :param theme: optional colour theme for this pop-up.  Defaults to the warning colours.
        The `on_close` method (if specified) will be called with one integer parameter that
        corresponds to the index of the button passed in the array of available `buttons`.
        Note that `on_close` must be a static method to work across screen resizing.  Either it
        is static (and so the dialog will be cloned) or it is not (and the dialog will disappear
        when the screen is resized).
        """
        # Remember parameters for cloning.
        self._text = text
        self._buttons = buttons
        self._on_close = on_close

        # Decide on optimum width of the dialog.  Limit to 2/3 the screen width.
        string_len = wcswidth if screen.unicode_aware else len
        width = max([string_len(x) for x in text.split("\n")])
        width = max(width + 2,
                    sum([string_len(x) + 4 for x in buttons]) + len(buttons) + 5)
        width = min(width, screen.width * 2 // 3)

        # Figure out the necessary message and allow for buttons and borders
        # when deciding on height.
        dh = 4 if len(buttons) > 0 else 2
        self._message = _split_text(text, width - 2, screen.height - dh, screen.unicode_aware)
        height = len(self._message) + dh

        # Construct the Frame
        self._data = {"message": self._message}
        super(PopUpDialogNoScroll, self).__init__(
            screen, height, width, self._data, has_shadow=has_shadow, is_modal=True, can_scroll=False)

        # Build up the message box
        layout = Layout([width - 2], fill_frame=True)
        self.add_layout(layout)
        text_box = TextBox(len(self._message), name="message")
        text_box.disabled = True
        layout.add_widget(text_box)
        layout2 = Layout([1 for _ in buttons])
        self.add_layout(layout2)
        for i, button in enumerate(buttons):
            func = partial(self._destroy, i)
            layout2.add_widget(Button(button, func), i)
        self.fix()

        # Ensure that we have the right palette in place
        self.set_theme(theme)

    def _destroy(self, selected):
        self._scene.remove_effect(self)
        if self._on_close:
            self._on_close(selected)

    def clone(self, screen, scene):
        """
        Create a clone of this Dialog into a new Screen.
        :param screen: The new Screen object to clone into.
        :param scene: The new Scene object to clone into.
        """
        # Only clone the object if the function is safe to do so.
        if self._on_close is None or isfunction(self._on_close):
            scene.add_effect(PopUpDialog(screen, self._text, self._buttons, self._on_close))

class DemoView(Frame):
    def __init__(self, screen):
        super(DemoView, self).__init__(screen,
                                          11,
                                          48,
                                          data=None,
                                          on_load=None,
                                          has_border=True,
                                          hover_focus=True,
                                          name=None,
                                          title="Welcome",
                                          x=None,
                                          y=None,
                                          has_shadow=False,
                                          reduce_cpu=False,
                                          is_modal=False,
                                          can_scroll=False)


        body = Layout([1], fill_frame=True)
        self.add_layout(body)
        button = Button("Click me", self.clicked, label=None)
        body.add_widget(button, 0)


    def clicked(self):
      self._scene.add_effect(
          PopUpDialogNoScroll(self.screen, "1..\n2..\n3..\n4..\n5..  ", ["OK"], on_close=self.done, has_shadow=False, theme='info'))

    def done(self):
        pass


last_scene = None

def demo(screen, scene):
  scenes = [
    Scene([DemoView(screen)], duration=-1, clear=True, name="demo"),
  ]

  screen.play(scenes, stop_on_resize=False, unhandled_input=None, start_scene=scene, repeat=True, allow_int=True)

Screen.wrapper(demo, catch_interrupt=True, arguments=[last_scene])