Kivy可滚动标签和文本文件，标签不会更新 [英] Kivy Scrollable Label and text file, label wont update

问题描述

问题在于，使用当前代码，到目前为止，除了文本编辑器外，其他什么都没有，当我尝试使用kv语言制作可滚动标签并在主屏幕上按推时调用它时，一个按钮，我没有任何错误，那里什么也没有.我应该提到文本是从存储的文件中提取的，唯一起作用的版本是带有常规标签的文本.这是代码，我知道它有点长，但是它的易懂性很容易理解，所以请和我在一起.非常感谢您提供任何意见，谢谢您抽出宝贵的时间.

Hy, the problem is that with the current code, which is at this point preety much nothing but a text editor, when ever I try to make a scrollable label in the kv language and call it on the main screen at the push of a button, I get no error, theres just nothing there. I should mention that the text is taken from a stored file, and the only version that works is with a regular label. This is the code, I know its a bit long but its preety easy to understand so stay with me. Any sort of input is greatly apreciated and I thank you for taking the time.

#kivy.require("1.8.0")
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen, FadeTransition
from kivy.uix.widget import Widget
from kivy.uix.scatter import Scatter
from kivy.uix.label import Label
from kivy.uix.scrollview import ScrollView
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.textinput import TextInput
from kivy.properties import StringProperty
from kivy.uix.boxlayout import BoxLayout
from kivy.graphics import Line
from kivy.uix.gridlayout import GridLayout


kv = '''
#: import FadeTransition kivy.uix.screenmanager.FadeTransition

ScreenManager:
    transition: FadeTransition()
    MainScreen:
    AddScreen:
    AppendScreen:


<ScatterTextWidget>:
    orientation: 'vertical'

    TextInput:
        id: main_input
        font_size: 14
        size_hint_y: None
        height: root.height - botones_layout.height
        font_color: [0.1,0.3,0.9,1]
        focus: True
        foreground_color: [0.2,0.5,0.9,1]
        cursor_color: [0,0,1,1]

    BoxLayout:
        id: botones_layout
        orientation: 'horizontal'
        height: 30
        Button:
            id: home_button
            text: "Back Home"            
        Button:
            id: save_button
            text: "Save to file"
            on_press: root.saveToFile("Archive.txt", main_input.text)


<AppendTextWidget>:
    orientation: 'vertical'

    TextInput:
        text: root.text
        id: main_input
        font_size: 14
        size_hint_y: None
        height: root.height - botones_layout.height
        font_color: [0.1,0.3,0.9,1]
        focus: True
        foreground_color: [0.2,0.5,0.9,1]
        cursor_color: [0,0,1,1]

    BoxLayout:
        id: botones_layout
        orientation: 'horizontal'
        height: 30
        Button:
            id: home_button
            text: "Back Home"
            on_release: app.root.current = "main"
        Button:
            id: save_button
            text: "Save"
            on_press: root.append(main_input.text)

#This does not work <--- <--- <---

<ScrollableLabel>:
    Label:
        text: root.text
        font_size: 15
        text_size: self.width, None
        color: [0,255,0,1]
        padding_x: 20
        size_hint_y: None
        pos_hint: {"left":1, "top":1}
        height: self.texture_size[1]


<MainScreen>:
    name: "main"
    FloatLayout:

        # This does work 

        Label:
            text: root.text
            font_size: 15
            text_size: self.width, None
            color: [0,255,0,1]
            padding_x: 20
            size_hint_y: None
            pos_hint: {"left":1, "top":1}
            height: self.texture_size[1]        

    ActionBar:
        pos_hint: {'top':1}
        ActionView:
            use_separator: True
            ActionPrevious:
                title: "Text"
                with_previous: False
            ActionOverflow:
            ActionButton:
                text: "New"
                on_release: app.root.current = "add"
            ActionButton:
                text: "Update"
                on_press: root.clicked()
            ActionButton:
                text: "Add"
                on_release: app.root.current = "append"


<AddScreen>:
    name: "add"
    FloatLayout:
         ScatterTextWidget

<AppendScreen>:
    name: "append"
    FloatLayout:
        AppendTextWidget        

'''


class ScatterTextWidget(BoxLayout):
    def saveToFile(self,name,text):
        f = open(name, "w")
        f.write("\n\n\n" + "    " + ">>>" + text + "test"*500)
        f.close()

class AppendTextWidget(BoxLayout):
    text = StringProperty("")
    def append(self,text):
        with open("Archive.txt", "a") as f:
            f.write("\n" + "    " + ">>>" + text)
            f.close()



 class ScrollableLabel(ScrollView):
     text = StringProperty('')
     pass


class MainScreen(Screen):
    text = StringProperty("")

    def clicked(self):
        with open("Archive.txt", "r") as f:
            contents = f.read()
            self.text = contents
    pass

class AddScreen(Screen):
    pass

class AppendScreen(Screen):
    pass    

class MyApp(App):

    def build(self):
        return Builder.load_string(kv)



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

推荐答案

为什么起作用:

您在MainScreen中的text已从文件更新，然后传递给Label，并加载了文本. ScrollableLabel.text保持不变.

Your text in MainScreen is updated from file, then passed to Label and the text is loaded. ScrollableLabel.text stays unchanged.

为什么它不能按预期工作:

Why it doesn't work as you expect:

类之间没有通信，因此只有text更改才是实际的self.text = MainScreen.text

There's no communication between your classes, therefore only text changed is an actual self.text = MainScreen.text

如何使其工作:

或者在全局范围内使用某些内容，即App类中的变量，然后使用a = App.get_running_app()并通过a.<variable>访问变量，或者使用__init__在MainScreen内部初始化ScrollableLabel并将其传递给text

Either use something on a global range, i.e. variable in your App class, then a = App.get_running_app() and access variable through a.<variable> or use __init__ to initialize your ScrollableLabel inside the MainScreen and pass it the text

因此，它基本上是这个的副本，并且是一个较旧的未简化问题的副本.

So it's basically a duplicate of this and that one is a duplicate of an older unsimplified question.

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