如何访问Kivy代码启动的类实例? [英] How to access class instance initiated by the Kivy code?

问题描述

我被困住了.我无法确定如何访问在Kivy文件中启动的对象?

I am stuck. I can't wrap my mind around how to access an object that is initiated in the Kivy file?

这是我的代码:

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
import time
from kivy.uix.screenmanager import Screen, ScreenManager

import filestack

Builder.load_file("test.kv")

class LoginScreen(Screen):

    def create_file(self):
        filename = f"file_{time.strftime('%Y%m%d_%H%M%S')}.txt"
        with open(filename, 'w') as file:
            file.write("Some content")


class RootWidget(ScreenManager):
    pass

class MainApp(App):
    def build(self):
        return RootWidget()

class FileSharer:

    def __init__(self, filepath, api_key="abcdefg"):
        self.filepath = filepath
        self.api_key = api_key

    def share(self):
        client = filestack.Client(self.api_key)
        new_filelink = client.upload(filepath=self.filepath)
        return new_filelink.url

MainApp().run()

和我的 test.kv 文件:

<LoginScreen>:
    GridLayout:
        cols: 1
        padding: 10, 10
        spacing: 10, 10
        Button:
            text: 'Create File'
            size_hint_y: None
            height: '48dp'
            on_press: root.create_file()

<RootWidget>:
    LoginScreen:
        id: login_screen
        name: "login_screen"

以下是程序产生的视觉效果:

Here's a visual of what the program produces:

当按下 Create File 按钮时，Kivy文件将调用 LoginScreen.create_file()方法，而文本文件的名称将包含当前时间戳记已创建(例如file_20200624_173229.txt).

When the Create File button is pressed, the LoginScreen.create_file() method is called by the Kivy file, and a text file with a name containing the current timestamp is created (e.g. file_20200624_173229.txt).

我希望能够从Python代码访问该文件名.我要这样做的原因是我想使用FileSharer类将文件上传到云中.为此，我需要像 FileSharer(filepath = ...)一样初始化 FileSharer .

I want to be able to access that filename from the Python code. The reason I want to do this is I want to upload the file to the cloud using the FileSharer class. In order to do that, I need to initlalize FileSharer like FileSharer(filepath=...).

我知道我可以通过使用 os.listdir()在磁盘中查找生成的文件来解决此问题，但是我想通过访问的值来正确地做到这一点. LoginScreen 实例中的 filename .

I know I can get around this by using os.listdir() to look for the generated files in the disk, but I want to do this the right way which is by accessing the value of filename from the LoginScreen instance.

推荐答案

几种方法可以实现此目的.这是一个.您可以在 LoginScreen 中创建一个 StringProperty 来包含创建的文件名:

Several ways to accomplish this. Here is one. You can create a StringProperty in the LoginScreen to contain the created filename:

class LoginScreen(Screen):
    filename = StringProperty('')

    def create_file(self):
        self.filename = f"file_{time.strftime('%Y%m%d_%H%M%S')}.txt"
        with open(self.filename, 'w') as file:
            file.write("Some content")

create_file()方法将文件名保存到 filename 属性.

And the create_file() method saves the file name to the filename property.

然后，您可以通过几种方式访问​​文件名，例如 login_screen_instance.filename ，或者利用它现在是 Property 的事实，可以在您的文件名中使用它. kv :

Then you can access the filename several ways, like login_screen_instance.filename, or taking advantage of the fact that it is now a Property, you can use it in your kv:

<RootWidget>:
    LoginScreen:
        id: login_screen
        name: "login_screen"
        on_filename: root.get_file(self.filename)

并向 RootWidget 中添加 get_file()方法:

class RootWidget(ScreenManager):
    def get_file(self, filename):
        print('file is', filename)

现在，每当通过 create_file()方法创建新文件时，就会调用 get_file()方法.

Now, whenever a new file is created by the create_file() method, the get_file() method is called.

这篇关于如何访问Kivy代码启动的类实例?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！