实施例

Question

所以我有两个文件：

returnStation.py
returnStationLayout.kv

我想要实现的目标：有两个屏幕。一个是数字键盘。键入数字并按Enter键后，它会进入下一个屏幕。我希望其他屏幕显示您刚刚输入的数字。

我面临的问题：我试图访问我想要更改的标签的ID以显示该号码但它无法正常工作：/我在终端中没有收到任何错误。

我能以错误的方式访问这些值吗？如果是这样，请告知如何以两个屏幕进行最佳操作。感谢任何帮助！

这是文件 - returnStation.py：

我如何尝试更改标签是通过getPoints（）

import kivy
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.gridlayout import GridLayout

class ScreenOne(Screen):
    pass

class ScreenTwo(Screen):
    pass

class PhoneGridLayout(GridLayout):

    def backspace(self, textString):
        newTextString = textString[0:-1]
        self.display.text = newTextString

    def getPoints(self, phoneNumber):
        st = ScreenTwo()
        st.ids.memberStatus.text = phoneNumber   #THIS IS HOW I ATTEMPTED TO CHANGE THE LABEL

class ReturnStationLayoutApp(App):
    pass


mainscreen = ScreenOne()
mainlayout = PhoneGridLayout()
mainscreen.add_widget(mainlayout)

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

这是文件 - returnStationLayout.kv：

我想要改变的标签一直在这个文件的底部

ScreenManager:
    id: screen_manager
    ScreenOne:
        id: screen_one
        name: 'menu'
        manager: 'screen_manager'
    ScreenTwo:
        id: screen_two
        name: 'settings'
        manager: 'screen_manager'

<CustButton@Button>:
    font_size: 32

<ScreenOne>:
    PhoneGridLayout:
        id: numberPad
        display: entry
        rows: 5
        padding: [300,200]
        spacing: 10

        # Where input is displayed
        BoxLayout:
            Label:
                text: "+65"
                font_size: 50
                size_hint: 0.2, 1
            TextInput:
                id: entry
                font_size: 50
                multiline: False
                padding: [20, ( self.height - self.line_height ) / 2]


        BoxLayout:
            spacing: 10
            CustButton:
                text: "1"
                on_press: entry.text += self.text
            CustButton:
                text: "2"
                on_press: entry.text += self.text
            CustButton:
                text: "3"
                on_press: entry.text += self.text
            CustButton:
                text: "DEL"
                on_press: numberPad.backspace(entry.text)

        BoxLayout:
            spacing: 10
            CustButton:
                text: "4"
                on_press: entry.text += self.text
            CustButton:
                text: "5"
                on_press: entry.text += self.text
            CustButton:
                text: "6"
                on_press: entry.text += self.text
            CustButton:
                text: "AC"
                on_press: entry.text = ""

        BoxLayout:
            spacing: 10
            CustButton:
                text: "7"
                on_press: entry.text += self.text
            CustButton:
                text: "8"
                on_press: entry.text += self.text
            CustButton:
                text: "9"
                on_press: entry.text += self.text
            CustButton:
                text: "Enter" #HERE IS THE ENTER BUTTON
                on_press:
                    app.root.transition.direction = 'left'
                    app.root.transition.duration = 1
                    app.root.current = 'settings'
                    numberPad.getPoints(entry.text)

        BoxLayout:
            spacing: 10
            Label:
                text: ""
            CustButton:
                text: "0"
                on_press: entry.text += self.text
            Label:
                text: ""
            Label:
                text: ""

<ScreenTwo>:
    BoxLayout:
        Label:
            id: memberStatus
            text: ''  #THIS IS THE LABEL I AM TRYING TO CHANGE
        Button:
            text: 'Back to menu'
            on_press:
                app.root.transition.direction = "right"
                app.root.current = 'menu'

Answer 1

您可以应用的最小修复方法是将getPoints方法移至ReturnStationLayoutApp类，并从那里更新所需字段，如下所示：

class ReturnStationLayoutApp(App):

    def getPoints(self, phoneNumber):
        self.root.ids.screen_two.ids.memberStatus.text = phoneNumber

当然，这需要将.kv文件中的numberPad.getPoints(entry.text)行更改为app.getPoints(entry.text)。

Answer 2

使用Kivy ObjectProperty 和 ScreenManager ，您可以在kv文件中使用 root.manager ... 并使用 self.manager < / em>在Python脚本中。

有关详细信息，请参阅以下建议和示例。

为ScreenManager定义一个类，并为ScreenOne和ScreenTwo声明ObjectProperty。

使用ScreenManager，将 app.root ... 替换为kv文件中的 root.manager ... 。

在ScreenOne类中实现PhoneGridLayout类中的两个方法，并删除类PhoneGridLayout

在ScreenTwo类中声明memberStatus的ObjectProperty。

删除st = ScreenTwo()因为不想实例化ScreenTwo的另一个对象，该对象与已经在kv文件中实例化的对象不同。

使用 self.manager.screen_two.member_status.text
替换 st.ids.memberStatus.text
Screen Manager » Basic Usage


创建两个屏幕。请注意root.manager.current：这是怎么回事   你可以从kv控制ScreenManager。默认情况下每个屏幕都有一个   属性管理器，为您提供所用ScreenManager的实例。

Programming Guide » Kv language


尽管self.ids方法非常简洁，但它通常被认为是使用ObjectProperty的“最佳实践”。这样可以创建直接引用，提供更快的访问速度，并且更加明确。

实施例

returnStation.py

from kivy.app import App from kivy.uix.screenmanager import ScreenManager, Screen from kivy.properties import ObjectProperty class ScreenManagement(ScreenManager): screen_one = ObjectProperty(None) screen_two = ObjectProperty(None) class ScreenOne(Screen): member_status = ObjectProperty(None) def backspace(self, textString): newTextString = textString[0:-1] self.display.text = newTextString def getPoints(self, phoneNumber): print(phoneNumber) self.manager.screen_two.member_status.text = phoneNumber #THIS IS HOW I ATTEMPTED TO CHANGE THE LABEL class ScreenTwo(Screen): pass class ReturnStationLayoutApp(App): def build(self): return ScreenManagement() if __name__ == '__main__': ReturnStationLayoutApp().run()

returnstationlayout.kv

#:kivy 1.10.0 <ScreenManagement>: screen_one: screen_one screen_two: screen_two ScreenOne: id: screen_one name: 'menu' ScreenTwo: id: screen_two name: 'settings' <CustButton@Button>: font_size: 32 <ScreenOne>: display: entry # PhoneGridLayout GridLayout: id: numberPad rows: 5 padding: [300,200] spacing: 10 # Where input is displayed BoxLayout: Label: text: "+65" font_size: 50 size_hint: 0.2, 1 TextInput: id: entry font_size: 50 multiline: False padding: [20, ( self.height - self.line_height ) / 2] BoxLayout: spacing: 10 CustButton: text: "1" on_press: entry.text += self.text CustButton: text: "2" on_press: entry.text += self.text CustButton: text: "3" on_press: entry.text += self.text CustButton: text: "DEL" on_press: root.backspace(entry.text) BoxLayout: spacing: 10 CustButton: text: "4" on_press: entry.text += self.text CustButton: text: "5" on_press: entry.text += self.text CustButton: text: "6" on_press: entry.text += self.text CustButton: text: "AC" on_press: entry.text = "" BoxLayout: spacing: 10 CustButton: text: "7" on_press: entry.text += self.text CustButton: text: "8" on_press: entry.text += self.text CustButton: text: "9" on_press: entry.text += self.text CustButton: text: "Enter" #HERE IS THE ENTER BUTTON on_press: root.manager.transition.direction = 'left' root.manager.transition.duration = 1 root.manager.current = 'settings' root.getPoints(entry.text) BoxLayout: spacing: 10 Label: text: "" CustButton: text: "0" on_press: entry.text += self.text Label: text: "" Label: text: "" <ScreenTwo>: member_status: memberStatus BoxLayout: Label: id: memberStatus text: '' #THIS IS THE LABEL I AM TRYING TO CHANGE Button: text: 'Back to menu' on_press: root.manager.transition.direction = "right" root.manager.current = 'menu'

输出

标签没有更新Kivy

2 个答案:

实施例

returnStation.py

returnstationlayout.kv

输出