問題描述

我想向我的 kivy 應用程序添加一個額外的類，它只是一個信息存儲庫.我不確定在哪里執行此操作，或者是否建議使用這種方法.

I want to add an additional class to my kivy app that is just an info storage depot. I'm not sure where to do this or if this approach is even advised.

該應用有多個屏幕.每個屏幕都允許用戶進行選擇.用戶的選擇就是我想要存儲在附加類中的內容.附加類將存儲數據，然后最終使用 MQTT 將數據發送出去.另外，我想將類定義保存在一個單獨的文件中，這樣我就可以將程序組織成邏輯有序的塊.

The app has multiple screens. Each screen allows the user to make a selection. The user's selection is what I want to store in the additional class. The additional class will store data then ultimately use MQTT to send the data out. Also, I wanted to keep the class definition in a separate file so I could organize the program into logically ordered chunks.

(請記住，我只分享了一小部分代碼，但這應該足以表達我的問題)

(keep in mind I'm sharing a small fraction of the code, but this should be representative enough to convey my question)

我的 kivy python 代碼:

My kivy python code:

from kivy.app import App
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.screenmanager import ScreenManager, Screen
from storage import Storage  # <<========================== this is the addtional class

# Screen Manager
class MyScreenManager(ScreenManager):
    pass


# Background Color
class BG(FloatLayout):
    pass


class VendorScreen(Screen):
    pass


class InvoiceScreen(Screen):
    def __init__(self, **kwargs):
        super(InvoiceScreen, self).__init__(**kwargs)
        self.invoice = ''

    def keyEntry(self, number):  # ............ Digit Pressed
        invoice = self.ids.invoice  # ......... link to kivy Label
        invoice.text += number  # ............. append number to invoice

    def keyBack(self):  # ..................... Backspace
        invoice = self.ids.invoice  # ......... link to kivy Label
        invoice.text = invoice.text[:-1]  # ... remove last digit

    def set_invoice(self):
        invoice = self.ids.invoice
        self.invoice = invoice.text


class MainControlScreen(Screen):
    pass


# Main-Execution
class mySuperApp(App):
    def build(self):
        return MyScreenManager()


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

我的kv碼:

#:kivy 1.0.9

<MyScreenManager>:
    VendorScreen:  # ........ Incoming Delivery, Screen 2b
        name: 'vendor_screen'
    InvoiceScreen: # ........ .................. Screen 3b
        name: 'invoice_screen'
    MainControlScreen:  # ... .................. Screen 4b
        name: 'main_control_screen'

<BG>
    AsyncImage:
        source: 'img/screen1_background4.png'
        size_hint: 1, 1

<VendorScreen>
    BG:
    FloatLayout:
        Button:
            text: 'name1'
            color: 1.0, 0.6, 0.0, 1
            font_size: 40
            size_hint_x: 0.45
            size_hint_y: 0.35
            pos_hint: {'x': 0.03, 'y': 0.50}
            on_release:
                root.manager.transition.direction = 'left'
                root.manager.current = 'invoice_screen'
        Button:
            text: 'name2'
            color: 1.0, 0.6, 0.0, 1
            font_size: 40
            size_hint_x: 0.45
            size_hint_y: 0.35
            pos_hint: {'x': 0.52, 'y': 0.50}
            on_release:
                root.manager.transition.direction = 'left'
                root.manager.current = 'invoice_screen'
        Button:
            text: 'name3'
            color: 1.0, 0.6, 0.0, 1
            font_size: 40
            size_hint_x: 0.45
            size_hint_y: 0.35
            pos_hint: {'x': 0.03, 'y': 0.10}
            on_release:
                root.manager.transition.direction = 'left'
                root.manager.current = 'invoice_screen'
        Button:
            text: 'name4'
            color: 1.0, 0.6, 0.0, 1
            font_size: 40
            size_hint_x: 0.45
            size_hint_y: 0.35
            pos_hint: {'x': 0.52, 'y': 0.10}
            on_release:
                root.manager.transition.direction = 'left'
                root.manager.current = 'invoice_screen'

<InvoiceScreen>
    BG:
        canvas:
            Color:
                rgba: 0.90, 0.90, 0.90, 0.5
            Rectangle:
                pos: (40, 295)
                size: (320, 35)
            Color:
                rgba: 0, 0, 0, 1
            Line:
                points: 40, 295, 360, 295, 360, 330, 40, 330, 40, 295
                width: 1
    BoxLayout:
        orientation: 'horizontal'  # break it up into left / right
        FloatLayout:
            Label:
                pos_hint: {'x':0, 'y':.25}
                font_size: 30
                text: 'Enter Invoice Number'
                color: 0.1, 0.1, 1, 1
            Label:
                id: invoice
                pos_hint: {'x':0, 'y':.15}
                font_size: 30
                text: ''  # initially blank
                color: 0, 0, 0, 1
        GridLayout:
            cols: 3  # number of columns
            rows: 4  # number of rows
            Button:
                text: '1'
                on_release: root.keyEntry('1')
            Button:
                text: '2'
                on_release: root.keyEntry('2')
            Button:
                text: '3'
                on_release: root.keyEntry('3')
            Button:
                text: '4'
                on_release: root.keyEntry('4')
            Button:
                text: '5'
                on_release: root.keyEntry('5')
            Button:
                text: '6'
                on_release: root.keyEntry('6')
            Button:
                text: '7'
                on_release: root.keyEntry('7')
            Button:
                text: '8'
                on_release: root.keyEntry('8')
            Button:
                text: '9'
                on_release: root.keyEntry('9')
            Button:
                text: '< DEL'
                on_release: root.keyBack()
            Button:
                text: '0'
                on_release: root.keyEntry('0')
            Button:
                text: 'Done'
                on_release:
                    root.set_invoice()
                    root.manager.transition.direction = 'left'
                    root.manager.current = 'main_control_screen'

<MainControlScreen>
    BG:
        canvas:
            Color:
                rgba: 0, 0, 1, 1
            Line:
                points: 500, 180, 770, 180, 770, 450, 500, 450, 500, 180
                width: 3
    FloatLayout:
        Label:  # foreground
            pos_hint: {'x': 0.30, 'y': 0.13}
            font_size: 80
            text: '5'
            color: 1.0, 0.6, 0.0, 1
        Button:
            size_hint_x: 0.2
            size_hint_y: 0.1
            pos_hint: {'x': 0.05, 'y': 0.05}
            text: 'Auto-Reject'
            on_release:
                root.manager.transition.direction = 'up'
                root.manager.current = 'vendor_screen'
        Button:
            size_hint_x: 0.2
            size_hint_y: 0.1
            pos_hint: {'x': 0.75, 'y': 0.05}
            text: 'Photo' 
            on_release:
                root.manager.transition.direction = 'left'
                root.manager.current = 'invoice_screen'

最后是我的額外課程:

from datetime import datetime, date
import calendar


class Storage(object):
    def __init__(self):
        self.invoice = 0
        self.unit_name = ''
        self.unit_number = ''
        self.receiver = ''
        self.vendor = ''
        self.day = calendar.day_name[date.today().weekday()]
        self.delivery_time = datetime.now()  
        self.package_condition = True
        self.email = ''
        self.location = ('32.0, -117.0',)
        self.duration = 0  
        self.img = 'img.jpg'

所以我的問題是，我在哪里以及如何使用我的附加類存儲"?我希望所有 kivy 類都能夠訪問它的單個實例，但我不知道該怎么做.

So my question is, where and how do I use my addtional class 'Storage'? I want all the kivy classes to be able to access a single instance of it, but I cannot figure out how to do that.

我嘗試在 mySuperApp().run() 之前實例化一個類，但我無法在其他類中訪問它.我嘗試使用 global 來訪問該實例，但這不起作用.

I tried instantiating a class just before mySuperApp().run() but I cannot access it inside the other classes. I tried using global to access the instance, but that didn't work.

我考慮過從類繼承，但我不知道如何做到這一點......我從不同屏幕中的 Storage 繼承開始，但是，這不允許我訪問包含所有數據的單個實例是，我不得不從多個類中提取實例變量來收集完整的數據集.然后我嘗試在 Storage 中繼承 mySuperApp，然后從 Storage 中運行 ScreenManager，但這不起作用.它運行了，但我無法從其他類訪問實例變量.也許我需要在所有其他類中繼續從 Storage 繼承?

I thought about inheriting from the class, but I'm not sure how to do this... I started by inheriting from Storage in my different screens, however, that does not let me access a single instance where all my data is, rather I would have to pull instance variables from multiple classes to amass the full data set. Then I tried inheriting mySuperApp in Storage, then running the ScreenManager from Storage, but that didn't work. It ran, but I couldn't access the instance variables from the other classes. Maybe I need to keep inheriting from Storage in all the other classes?

我不確定如何處理這個問題，因為 kivy 部分只是程序的一小部分.最后，我將需要幾個額外的課程，但我不明白如何或在哪里鏈接這些課程.獲得概念后，我會將其應用于其他必要的課程，但我不知道從哪里開始.

I'm not sure how to approach this as the kivy part is only a fraction of the program. In the end I will need several additional classes, but I don't understand how or where to link these. Once I get the concept I will apply it to the other necessary classes, but I don't know where to start.

推薦答案

您可以使用 ScreenManager 來共享數據.
ScreenManager 將始終是所有屏幕的父級.因此，您可以通過以下三種方式訪問??管理器.

You could use the ScreenManager to share data.
The ScreenManager will allways be parent of all the screens. So here are three ways you can access the manager.

root.manager:
Screen 都有一個名為 manager 的屬性，也就是這個 Screen 所在的 ScreenManager.所以您可以從任何這樣的屏幕訪問它.

root.manager:
The Screen's all have an attribute called manager, which is the ScreenManager which this Screen is in. So you can access it from any screen like this.

root.parent:
如果 Widget 位于另一個小部件中，它們都將具有它的 parent.在這種情況下，Screen 的父級是 ScreenManager.因此，您可以從任何這樣的屏幕訪問它.

root.parent:
The Widget's if they are in another widget will all have it's parent. In this case, the Screen's parent is the ScreenManager. So you can access it from any screen like this.

app.root:
每個應用程序都有一個 root.在這種情況下，應用程序的根是 ScreenManager.所以你可以像這樣從任何地方訪問它.

app.root:
Every app has a root. In this case the root of the app, is the ScreenManager. So you can access it from anywhere like this.

試試這個例子，用三個按鈕演示:

Try this example, with three buttons demonstrating this:

from kivy.app import App
from kivy.uix.screenmanager import Screen, ScreenManager
from kivy.lang import Builder
from kivy.properties import StringProperty


class MyScreenManager(ScreenManager):
    shared_data = StringProperty("")


class Screen1(Screen):
    pass

class Screen2(Screen):
    pass


root = Builder.load_string('''

<Screen1>:
    name: "screen1"
    BoxLayout:
        orientation: "vertical"
        TextInput:
            on_text:
                root.manager.shared_data = self.text
        Label:
            text:
                root.manager.shared_data
        Button:
            text: "Go to screen2"
            on_release: root.manager.current = "screen2"

        Button:
            text: "root.manager.shared_data"
            on_release:
                print(root.manager.shared_data)
        Button:
            text: "root.parent.shared_data"
            on_release:
                print(root.parent.shared_data)
        Button:
            text: "app.root.shared_data"
            on_release:
                print(app.root.shared_data)



<Screen2>:
    name: "screen2"
    BoxLayout:
        orientation: "vertical"
        TextInput:
            on_text:
                root.manager.shared_data = self.text
        Label:
            text:
                root.manager.shared_data
        Button:
            text: "Go to screen1"
            on_release: root.manager.current = "screen1"


MyScreenManager:
    Screen1:
    Screen2:

''')



class MyApp(App):
    def build(self):
        return root

這篇關于kivy 使用附加類來存儲來自多個屏幕的數據的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！