通过列表动态生成它时更新屏幕上的kivy标签？

Question

首先，免责声明：我对编程非常陌生，并且正在尝试建立我对这个项目的理解。另外，让我说我已经搜索了论坛并找到了与我类似的帖子，但是没有更新通过列表动态生成的标签的问题。

我的问题在我的代码中，已被注释掉，但总结一下：我为列表中的每个项目生成按钮和标签。然后按钮应该从字典中的链接值中添加和减去。目前代码会这样做，但屏幕上的标签不会更新以反映新值。有人可以在调用 updateup 和 updatedown 时协助更新“ordlayout.add_widget(ordlayout.lbl[str(i)])”的值吗？

import kivy
kivy.require('1.10.0')
from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.uix.widget import Widget
from kivy.properties import ObjectProperty
from kivy.uix.behaviors import ButtonBehavior
from kivy.uix.gridlayout import GridLayout
from kivy.uix.scrollview import ScrollView
from kivy.uix.textinput import TextInput
from kivy.lang import Builder
from kivy.uix.dropdown import DropDown
from kivy.base import runTouchApp
from kivy.uix.screenmanager import ScreenManager, Screen, FadeTransition
from functools import partial
#The first screen the app opens to. Contains all other screen branches.
class MainScreen(Screen):
    pass

#NewOrder will be the screen used for choosing which
#items/and how many of each the customer wants added.
class NewOrder(Screen):
    def __init__(self, **kwargs):
        super(NewOrder, self).__init__(**kwargs)
        #This will eventually read/create a list of strings from a user-modified file.
        self.foods = ["Puppy", "Cat", "Fish"]
        #I create a dictionary linking a number to each item.
        self.countfoods = {}
        for i in self.foods:
            self.countfoods[i] = 0
        #Now I create a grid layout to put on the screen.
        ordlayout = GridLayout()
        ordlayout.cols = 8
        ordlayout.row_default_height=20
        ordlayout.buttons={}
        ordlayout.btns1 = {}
        ordlayout.lbl = {}
        #The items I want on the screen are 1.)First item from list. 2.) Minus button.
        #3.) Current number of the item. 4.) Plus button.
        #I want these four buttons for each item.
        for i in self.countfoods:
            #Adds text for first item.
            ordlayout.add_widget(Label(text=i))
            #Adds a button for minus, linked to a unique dict value.
            ordlayout.buttons[str(i)] = Button(text="-")
            ordlayout.lbl[str(i)] = Label(text=str((self.countfoods[i])))
            #The below assigns the specific object location of each label
            #to a variable for passing to ocuntup and countdown.
            tempPlacement = str(ordlayout.lbl[str(i)])
            ordlayout.buttons[str(i)].bind(on_press=partial(self.updatedown, i))
            ordlayout.add_widget(ordlayout.buttons[str(i)])
            #Add the value that I want to update.
            ordlayout.add_widget(ordlayout.lbl[str(i)])
            #Adds a button for addition, but doesn't properly link it to a specific value.
            ordlayout.btns1[str(i)] = Button(text="+")
            ordlayout.btns1[str(i)].bind(on_press=partial(self.updateup, i))
            ordlayout.add_widget(ordlayout.btns1[str(i)])
        #Add that grid wit
            h values to the screen.
        self.add_widget(ordlayout)

    #Function used to change value down by one.
    def updatedown(self, event, i):
        self.countfoods[event] -= 1
        print (self.countfoods)

    #Function used to change value up by one.
    def updateup(self, event, i):
        self.countfoods[event] += 1
        print (self.countfoods)


#AdminOpt will be the screen used for
class AdminOpt(Screen):
    def __init__(self, **kwargs):
        super(AdminOpt, self).__init__(**kwargs)

#Will allow for opening and checking of created orders.
class OrdHist(Screen):
    pass

#This is purely the class used for managing the other screens.
class ScreenManagement(ScreenManager):
    pass


Main = Builder.load_file("Order Handler2.kv")


class Customer:
    def __init__(self, name, pricelist):
        self.name = name
        self.pricelist = pricelist


class SimpleKivy(App):
    def build(self):
        return Main


if __name__== "__main__":
    SimpleKivy().run()

Answer 1

无法对此进行测试（您的问题缺少您的 kv 文件），但类似的方法可能有效：

#Function used to change value down by one.
def updatedown(self, i, button):
    self.countfoods[i] -= 1
    self.ordlayout.lbl[str(i)].text = str(self.countfoods[i])
    print (self.countfoods)

#Function used to change value up by one.
def updateup(self, i, button):
    self.countfoods[i] += 1
    self.ordlayout.lbl[str(i)].text = str(self.countfoods[i])
    print (self.countfoods)

您还需要在 __init__() 方法中将每次出现的 ordlayout 替换为 self.ordlayout。

顺便说一句，您不需要为您的字典键执行str(i)。事实上，如果您愿意，可以使用列表代替字典。