用Python在Kivy中输入数字

Question

我对Kivy非常陌生，找到了一个简单计算器的在线示例here，我想用Kivy examples~/examples/keyboard来修改它/主.py. 在这个例子中是一个数字键盘，但我似乎不知道如何让它出现而不是标准键盘。如能提供帮助或建议，我们将不胜感激。在

以下是我的开场白：

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.floatlayout import FloatLayout
from kivy.core.window import Window
from kivy.uix.vkeyboard import VKeyboard
from kivy.properties import ObjectProperty
from kivy.uix.button import Button
from kivy.config import Config
from kivy.uix.screenmanager import Screen, ScreenManager
from kivy import require
Builder.load_string("""
<KeyboardScreen>:
    displayLabel: displayLabel
    kbContainer: kbContainer
    BoxLayout:
        orientation: 'vertical'
        Label:
            size_hint_y: 0.15
            text: "Available Keyboard Layouts"
        BoxLayout:
            id: kbContainer
            size_hint_y: 0.2
            orientation:"horizontal"
            padding: 10
        Label:
            id: displayLabel
            size_hint_y: 0.15
            markup: True
            text: "[b]Key pressed[/b] - None"
            halign: "center"
        Button:
            text: "Back"
            size_hint_y: 0.1
            on_release: root.manager.current = "mode"
        Widget:
            # Just a space taker to allow for the popup keyboard
            size_hint_y: 0.5

<Calc>:
    # This are attributes of the class Calc now
    a: _a
    b: _b
    result: _result
    KeyboardScreen:
    AnchorLayout:
        anchor_x: 'center'
        anchor_y: 'top'
        ScreenManager:
            size_hint: 1, .9
            id: _screen_manager
            Screen:
                name: 'screen1'
                GridLayout:
                    cols:1
#                    TextInput:
                    Button:
                        id: _a
                        text: '3'
                        on_press:KeyboardScreen(name="keyboard")
#                    TextInput:
                    Button:
                        id: _b
                        text: '5'
                        on_press:KeyboardScreen(name="keyboard")
                    Label:
                        id: _result
                    Button:
                        text: 'sum'
                        # You can do the opertion directly
                        on_press: _result.text = str(int(_a.text) + int(_b.text))
                    Button:
                        text: 'product'
                        # Or you can call a method from the root class (instance of calc)
                        on_press: root.product(*args)
        Screen:
            name: 'screen2'
            Label:
                text: 'The second screen'
    AnchorLayout:
        anchor_x: 'center'
        anchor_y: 'bottom'
        BoxLayout:
            orientation: 'horizontal'
            size_hint: 1, .1
            Button:
                text: 'Go to Screen 1'
                on_press: _screen_manager.current = 'screen1'
            Button:
                text: 'Go to Screen 2'
                on_press: _screen_manager.current = 'screen2'""")

class Calc(FloatLayout):
    # define the multiplication of a function
    def product(self, instance):
        # self.result, self.a and self.b where defined explicitely in the     kv
        self.result.text = str(int(self.a.text) * int(self.b.text))

class KeyboardScreen(Screen):
    def __init__(self, **kwargs):
        super(KeyboardScreen, self).__init__(**kwargs)
#       self._add_keyboards()
        self.set_layout("numeric.json","numeric.json")
        self._keyboard = None

    def set_layout(self, layout, button):
        """ Change the keyboard layout to the one specified by *layout*. """
        kb = Window.request_keyboard(
        self._keyboard_close, self)
        if kb.widget:
        # If the current configuration supports Virtual Keyboards, this
        # widget will be a kivy.uix.vkeyboard.VKeyboard instance.
            self._keyboard = kb.widget
            self._keyboard.layout = layout
        else:
            self._keyboard = kb

        self._keyboard.bind(on_key_down=self.key_down,on_key_up=self.key_up)

    def _keyboard_close(self, *args):
        """ The active keyboard is being closed. """
        if self._keyboard:
            self._keyboard.unbind(on_key_down=self.key_down)
            self._keyboard.unbind(on_key_up=self.key_up)
            self._keyboard = None

    def key_down(self, keyboard, keycode, text, modifiers):
        """ The callback function that catches keyboard events. """
        self.displayLabel.text = u"Key pressed - {0}".format(text)

        # def key_up(self, keyboard, keycode):

    def key_up(self, keyboard, keycode, *args):
        """ The callback function that catches keyboard events. """
        # system keyboard keycode: (122, 'z')
        # dock keyboard keycode: 'z'
        if isinstance(keycode, tuple):
            keycode = keycode[1]
            self.displayLabel.text += u" (up {0})".format(keycode)

class TestApp(App):
    sm = None  # The root screen manager
    Config.set("kivy", "keyboard_mode", 'dock')
    Config.write()

    def build(self):
#           self.sm = ScreenManager()
#        self.sm.add_widget(KeyboardScreen(name="keyboard"))
        return Calc()

if __name__ == '__main__':
    TestApp().run()