使用 Kivy 屏幕，如何根据屏幕 1 上按下按钮的文本更改屏幕 2 的标签？

Question

我在这个过程中使用了 2 个文件，第一个是main.py ，第二个是ScreenManagement.kv我已经尝试了 Stack 和其他站点的许多不同的“解决方案”，但没有什么对我有用。 我希望能够单击一个按钮，该按钮会将我带到下一个屏幕，但还将该屏幕中的标签设置为第一个屏幕中按钮的文本。

我用评论标记了有问题的按钮、标签和屏幕。 提前感谢您的帮助，因为这是一个持续存在的问题:)

主文件

from kivy.app import App
from kivy.graphics import Color, Rectangle
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.gridlayout import GridLayout
from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.uix.textinput import TextInput
from kivy.uix.colorpicker import ColorPicker
from py.fileImport import readMachine
from kivy.lang import Builder
from kivy.uix.anchorlayout import AnchorLayout
from kivy.uix.stacklayout import StackLayout
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.screenmanager import Screen, ScreenManager, NoTransition
from kivy.properties import StringProperty

Builder.load_file("kv/ScreenManagement.kv")

class MainOverview(Screen): #This is the first screen in question
    selectedMachine = StringProperty("")
class MachineStatusPage(Screen): #This is the second screen in question
    selectedMachine = StringProperty("test")
class AddMachinePage(Screen):
    pass
class AddJobPage(Screen):
    pass

class MainApp(App):   

    def build(self):
        
        self.root = root = ScreenManager()
        root.bind(size=self._update_rect, pos=self._update_rect)
        screen1 = MainOverview(name='MainOverview')
        screen2 = MachineStatusPage(name='MachineStatusPage')
        screen3 = AddMachinePage(name='AddMachinePage')
        screen4 = AddJobPage(name='AddJobPage')
        root.add_widget(screen1)
        root.add_widget(screen2)
        root.add_widget(screen3)
        root.add_widget(screen4)
        

        with root.canvas.before:
            Color(0, 1, 1, .6)  # colors range from 0-1 not 0-255
            self.rect = Rectangle(size=root.size, pos=root.pos)
        return root

    def _update_rect(self, instance, value):
        self.rect.pos = instance.pos
        self.rect.size = instance.size

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

屏幕管理.kv

#:kivy 1.10.1
#: import NoTransition kivy.uix.screenmanager.NoTransition

<AnchorGridCell@AnchorLayout>:
    anchor_x: 'center'
    anchor_y: 'center'
<SubmitButton@Button>:
    text: 'Submit'
    font_size: self.width / 8
    size_hint: .4, .1
<CancelButton@Button>:
    text: 'Cancel'
    font_size: self.width / 8
    size_hint: .4, .1
<MachineButton@Button>:
    font_size: self.width / 20
    text_size: self.size
    halign: 'center'
    valign: 'center'
<MachineStatusButton@Button>:
    font_size: self.width / 9
    text_size: self.size
    halign: 'center'
    valign: 'center'
    size_hint: .3, .06
<XButton@Button>:
    text: 'X'
    size_hint: None, None
<InputLabel@Label>:
    font_size: self.width / 8
    text_size: self.size
    halign: 'left'
    valign: 'center'
<OutputLabel@Label>:
    font_size: self.width / 8
    text_size: self.size
    halign: 'right'
    valign: 'center'
<TextCollection@TextInput>:
    multiline: False
    size_hint: 1, .7
    font_size: self.width / 7
    
<ScreenManager>
    transition: NoTransition()
    MainOverview:
        id: mainOverview
    MachineStatusPage:
        selectedMachine: mainOverview.selectedMachine
<MainOverview>:
    FloatLayout:
        AnchorLayout:
            anchor_x: 'center'
            anchor_y: 'top'
            GridLayout:
                cols: 1
                row_force_default: True
                row_default_height: self.width / 13
                padding: self.width / 15
                AnchorLayout:
                    anchor_x: 'center'
                    anchor_y: 'bottom'
                    Label:
                        text: 'All Currently Added Machines'
                        text_size: self.size
                        font_size: self.width / 16
                        halign: 'center'
                        valign: 'bottom'
                AnchorLayout:
                    anchor_x: 'center'
                    anchor_y: 'top'
                    GridLayout:
                        cols: 1
                        row_force_default: True
                        row_default_height: self.width / 8
                        col_default_width: self.width / 4
                        padding: self.width / 25
                        spacing: self.width / 25, self.width / 50
                        AnchorGridCell:

###############################################################################

                            MachineButton: #This button is the one in question
                                id: machine1
                                text: "Tsugami 5"
                                on_press: root.selectedMachine = machine1.text; root.manager.current = 'MachineStatusPage'

###############################################################################

                        AnchorGridCell:
                            MachineButton:
                                text: 'Tsugami 6'
                                on_press: root.manager.current = 'MachineStatusPage'
                        AnchorGridCell:
                            MachineButton:
                                text: 'Tsugami 7'
                                on_press: root.manager.current = 'MachineStatusPage'
                        AnchorGridCell:
                            MachineButton:
                                text: 'Tsugami 8'
                                on_press: root.manager.current = 'MachineStatusPage'
            AnchorLayout:
                anchor_x: 'right'
                anchor_y: 'bottom'
                MachineButton:
                    text: 'Add New Machine'
                    font_size: self.width / 8
                    size_hint: .4, .1
                    on_press: root.manager.current = 'AddMachinePage'
                                    
                                
<MachineStatusPage>:
    FloatLayout:
        AnchorLayout:
            anchor_x: 'center'
            anchor_y: 'top'
            GridLayout:
                cols: 1
                rows: 2
                row_force_default: True
                row_default_height: self.width / 13
                padding: self.width / 8
                AnchorLayout:
                    anchor_x: 'center'
                    anchor_y: 'bottom'

#####################################################################

                    Label: #This label is the label in question
                        id: selectedMachine
                        text: root.selectedMachine
                        text_size: self.size
                        font_size: self.width / 12
                        halign: 'center'
                        valign: 'bottom'

#####################################################################

                AnchorLayout:
                    anchor_x: 'center'
                    anchor_y: 'top'
                    GridLayout:
                        cols: 2
                        row_force_default: True
                        row_default_height: self.width / 8
                        col_default_width: self.width / 4
                        padding: self.width / 25
                        spacing: self.width / 25, self.width / 50
                        AnchorGridCell:
                            InputLabel:
                                text: 'Current Job: '
                        AnchorGridCell:
                            OutputLabel:
                                text: '414-44-1'
                        AnchorGridCell:
                            InputLabel:
                                text: 'Parts Left: '
                        AnchorGridCell:
                            OutputLabel:
                                text: '250'
                        AnchorGridCell:
                            InputLabel:
                                text: 'Time Left: '
                        AnchorGridCell:
                            OutputLabel:
                                text: '3 Days'
            AnchorLayout:
                anchor_x: 'left'
                anchor_y: 'bottom'
                Button:
                    text: 'Go Back'
                    font_size: self.width / 8
                    size_hint: .4, .1
                    on_press: root.manager.current = 'MainOverview'
            AnchorLayout:
                anchor_x: 'right'
                anchor_y: 'bottom'
                Button:
                    text: 'Add New Job'
                    font_size: self.width / 8
                    size_hint: .4, .1
                    on_press: root.manager.current = 'AddJobPage'

Answer 1

您可以使用方法get_screen或 attr。 current_screen以访问添加到ScreenManager （您的root小部件）的任何屏幕，

                            MachineButton: #This button is the one in question
                                id: machine1
                                text: "Tsugami 5"
                                on_press:
                                    root.manager.current = 'MachineStatusPage'
                                    root.manager.current_screen.selectedMachine = self.text
                                    # Or,
                                    # root.manager.get_screen('MachineStatusPage').selectedMachine = self.text

另外我认为您不需要以下代码行，因为您已经在方法build中定义了root 。

<ScreenManager> # Naming dynamic class with default class name is discouraged.
    transition: NoTransition()
    MainOverview:
        id: mainOverview
    MachineStatusPage:
        selectedMachine: mainOverview.selectedMachine