android之如何在 Kivy 中重置小部件

我有一个非常简单的应用程序，只有一个按钮和一个标签。标签最初的值为 0。每次按下按钮时，标签增加 1。当标签变为 3 时，我会显示一个带有“再次播放”按钮的弹出窗口。

现在，我想将标签重置为 0。

我的尝试:

#!/usr/bin/kivy 
import kivy 
kivy.require('1.7.2') 
 
from random import random 
from kivy.app import App 
from kivy.lang import Builder 
from kivy.uix.screenmanager import ScreenManager, Screen 
from kivy.uix.gridlayout import GridLayout 
from kivy.uix.boxlayout import BoxLayout 
from kivy.uix.button import Button 
from kivy.uix.label import Label 
from kivy.uix.popup import Popup 
from random import random 
from random import choice 
from kivy.properties import StringProperty 
import time 
from kivy.clock import Clock 
 
s=0 
 
def my_callback(dt): 
    mypopup = MyPopup() 
    return mypopup.show_popup() 
 
def go_to_main(self): 
    sm.current = 'menu' 
    global s 
    s=0 
 
def test(self): 
    global s 
    s=0 
    print s 
 
class MyPopup(Popup):  
    def show_popup(self): 
        mytext= str(s) 
        content = BoxLayout(orientation="vertical") 
        content.add_widget(Label(text="Game Over", font_size=20)) 
        content.add_widget(Label(text="Score", font_size=20)) 
        content.add_widget(Label(text=mytext, font_size=20)) 
        mybutton_cancel = Button(text="Play Again", size_hint_y=None, height=40) 
        content.add_widget(mybutton_cancel) 
        mypopup = Popup(content = content,               
            title = "oops",      
            auto_dismiss = False,          
            size_hint = (.5, .5)) 
        mybutton_cancel.bind(on_release=mypopup.dismiss) 
        mybutton_cancel.bind(on_release=test)  
        mypopup.open() 
 
Builder.load_string(""" 
<MenuScreen>: 
    GridLayout: 
        cols: 1 
        Button: 
            id: btn_0 
            text: "press me to increase score" 
            on_press: root.val0() 
        Label: 
            id: score 
            text:root.get_score() 
""") 
 
class MenuScreen(Screen): 
    def get_score(self): 
        return str(s) 
    #on_click of button code 
    def val0(self): 
        global s 
        s=s+1 
        self.ids['score'].text=str(s) 
        if(s==3): 
            Clock.schedule_once(my_callback, 0) 
 
sm = ScreenManager() 
sm.add_widget(MenuScreen(name='menu')) 
 
class TestApp(App): 
 
    def build(self): 
        return sm 
 
if __name__ == '__main__': 
    TestApp().run() 

它成功重置为 0，我将其打印在控制台上进行检查，但仍显示为 3。按下按钮时，更改为 1。我想将其显示为 0 而不是 3。

请您参考如下方法:

捕获你的 MenuScreen 对象

# sm.add_widget(MenuScreen(name='menu')) # Replace this line with these two: 
menu_screen = MenuScreen(name='menu') 
sm.add_widget(menu_screen) 

然后，在test 函数中，调用您的menu_screen val0 函数

def test(self): 
    global s 
    s=-1 
    menu_screen.val0()