Question

实际上，我有两个类似的问题：

可以访问类FaceNameTxtIn，捕获TextInput的文本，从TrainerBtn类不使用全局变量（例如，通过id，self.parent ......我试过没有成功）？
如何从TrainerBtn的on_release函数访问TrainerBoxLayout的trained_faces_value.text？根类的过程是：

self.root.ids.TrainerBoxLayout.ids.trained_faces_value.text

并且程序运行正常，因此我在self.parent（然后是self.parent.parent）中更改了self.root但是进程失败并返回＆＃39;流程已完成，退出代码为1＆＃39;。

（我已经在网上搜索了很多而没有找到符合我问题的解决方案）

FaceRec.py

Kivy图书馆

from kivy.app import App
from kivy.uix.screenmanager import ScreenManager,Screen
from kivy.uix.widget import Widget
from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.uix.textinput import TextInput
from kivy.uix.settings import SettingsWithSidebar
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.actionbar import ActionBar
from kivy.logger import Logger
from kivy.core.window import Window

HomeScreen类

class ScreenManagement(ScreenManager):
    pass

class HomeScreen(Screen):
    pass

class HomeActionBar(ActionBar):
    pass

class TitleLabel(Label):
    pass

class StatusBoxLayout(BoxLayout):
    pass

class ErrorsBoxLayout(BoxLayout):
    pass

class TrainerBoxLayout(BoxLayout):
    pass

class TrainerBtn(Button):
    def on_release(self):
        global face_name
        face_name = face_name.replace(' ','')
        ...

class FaceNameTxtIn(TextInput):
    def on_text(self,instance,value):
        global face_name
        face_name = value

class RecognizerBtn(Button):
    def on_release(self):
        ...

主要课程

class FaceRecApp(App):
    ...

    def build(self):
        self.root = HomeScreen()
        Logger.info('FaceRec.py: FaceRec.kv loaded')

        self.settings_cls = MySettingsWithSidebar
        Logger.info('FaceRec.py: MySettingsWithSidebar loaded')

        ...

        return self.root

    ...

补充工具栏设置

class MySettingsWithSidebar(SettingsWithSidebar):
    ...

执行

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

FaceRec.kv

#: import WipeTransition kivy.uix.screenmanager.WipeTransition

<ScreenManagement>:
    transition: WipeTransition()
    HomeScreen:

<HomeActionBar>:
    id: HomeActionBar
    background_color: 0.9,0.9,0.9,0.5
    pos_hint: {'top':1}
    size_hint_x: 1
    ActionView:
        use_separator: True
        ActionPrevious:
            title: 'Home'
            with_previous: False
        ActionOverflow:
        ActionButton:
            text: 'Logs'
            on_release:

        ActionButton:
            text: 'Settings'
            icon: 'settings.png'
            background_down: 'settings.png'
            on_release:
                app.open_settings()

<TitleLabel>:
    id: TitleLabel
    text: '[b]FaceRec[/b] - [i]The Face Recognition Project[/i]'
    color: 0.0,0.3,1,1
    markup: True
    font_size: 45

<StatusBoxLayout>:
    orientation: 'horizontal'
    Label:
        id: status
        text: 'Status: '
    Label:
        id: status_value
        text: 'Error'
        color: 1,0,0,1

<ErrorsBoxLayout>:
    id: ErrorsBoxLayout
    orientation: 'horizontal'
    Label:
        id: errors
        text: 'Errors No: '
    Label:
        id: errors_value
        text: '...'

<TrainerBoxLayout>:
    id: TrainerBoxLayout
    orientation: 'horizontal'
    Label:
        id: trained_faces
        text: 'Trained faces: '
    Label:
        id: trained_faces_value
        text: '...'

<TrainerBtn>:
    id: TrainerBtn
    text: 'Press to run the Face Trainer'
    font_size: 25
    size_hint: 0.5,1.4

<FaceNameTxtIn>:
    id: FaceNameTxtIn
    hint_text: 'Insert your name and then press the button below'
    font_size: 19
    size_hint: 0.5,1.4
    multiline: False

<RecognizerBtn>:
    id: RecognizerBtn
    text: 'Press to run the Face Recognizer'
    font_size: 25
    size_hint: 0.5,1.4

<HomeScreen>:
    id: HomeScreen
    name: 'HomeScreen'
    canvas.before:
        Rectangle:
            pos: self.pos
            size: self.size
            source: 'face_pointed.png'

    HomeActionBar:
        id: HomeActionBar

        BoxLayout:
        orientation: 'vertical'
        spacing: 70
        TitleLabel:
            id: TitleLabel

        BoxLayout:
            orientation: 'vertical'
            spacing: 20

            StatusBoxLayout:
                id: StatusBoxLayout
            ErrorsBoxLayout:
                id: ErrorsBoxLayout
            TrainerBoxLayout:
                id: TrainerBoxLayout

            FaceNameTxtIn:
                id: FaceNameTxtIn

            BoxLayout:
                orientation: 'horizontal'

                TrainerBtn:
                    id: TrainerBtn
                RecognizerBtn:
                    id: RecognizerBtn

            Label:
                text: 'Press q to quit the video'
                font_size: 20

感谢您的宝贵支持。

Answer 1

在Kivy内，有不同的可能性来访问其他类。

自我 ...是小部件本身
app ...是应用
root ...是当前班级的根
app.root ...是应用的根

您也可以使用父级和子级访问类，这通常是一个坏主意，因为每次更改结构时都必须调整路径。

一般来说，这些类很多人都知道，这是通过使用Kivy属性来完成的。

正如您在此示例中所看到的，您必须在要使用的上下文中定义属性。 Root经常是一个好地方。

以下示例演示了如何使用Properties来使用kv文件和python来操作数据。

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label

Builder.load_string('''
<MyLabel1>:
    text:"label 1"

<MyLabel2>
    text:"label 2"

<AppRoot>:
    lbl_1:lbl_1
    lbl_2:lbl_2
    btn_1:btn_1 
    MyLabel1:
        id: lbl_1
    BoxLayout:
        orientation:"vertical"
        BoxLayout:
            BoxLayout:
                Label:
                    text:"ignore this"
                MyLabel2: 
                    id:lbl_2
    Button:
        id:btn_1
        on_press: 
            root.lbl_2.text = root.lbl_1.text
            root.do_something_in_root()
            app.do_something_in_app()
''')

class MyLabel1(Label):
    pass

class MyLabel2(Label):
    pass

class AppRoot(BoxLayout):
    def do_something_in_root(self):
        print("AppRoot {}".format(self.lbl_1.text))
        self.lbl_2.text="set in AppRoot"

class TestApp(App):
    def build(self):
        return AppRoot()
    def do_something_in_app(self):
        print("App {}".format(self.root.lbl_2.text))
        self.root.lbl_1.text="set in APP"

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

在您的情况下，您可以使用以下方法（所有这些都在下面的代码中实现）：

直接来自KV档案
在HomeScreen的根目录

FaceNameTxtIn:FaceNameTxtIn
TrainerBtn:TrainerBtn
id: HomeScreen
name: 'HomeScreen'
canvas.before:
    Rectangle:
        pos: self.pos
        size: self.size
        source: 'face_pointed.png'

HomeActionBar:
    id: HomeActionBar

    BoxLayout:
    orientation: 'vertical'
    spacing: 70
    TitleLabel:
        id: TitleLabel

    BoxLayout:
        orientation: 'vertical'
        spacing: 20

        StatusBoxLayout:
            id: StatusBoxLayout
        ErrorsBoxLayout:
            id: ErrorsBoxLayout
        TrainerBoxLayout:
            id: TrainerBoxLayout

        FaceNameTxtIn:
            id: FaceNameTxtIn
            text:root.TrainerBtn.txt

        BoxLayout:
            orientation: 'horizontal'

            TrainerBtn:
                id: TrainerBtn
                on_press:
                    root.FaceNameTxtIn.text="on press from TrainerBtn"
                    root.on_press_from_btn()
                    app.on_press_from_bnt2()

            RecognizerBtn:
                id: RecognizerBtn

        Label:
            text: 'Press q to quit the video'
            font_size: 20

在Py文件中：

class HomeScreen(Screen):
    def __init__(self, **kwargs):
        super(HomeScreen, self).__init__(**kwargs)

    def on_press_from_btn(self):
        print("some button was pressed")
        # the property is defined in the kv
        self.FaceNameTxtIn.text="value changed from method in app"

class FaceRecApp(App):
    def on_press_from_bnt2(self):
        print("on press executed in app");
        app = App.get_running_app()
        app.root.FaceNameTxtIn.text="value changed from method in app"

有没有办法从另一个辅助类访问非root类？

1 个答案: