从现有实例调用方法 [英] Calling a method from an existing instance

问题描述

我对面向对象编程的理解有点不稳定，所以如果你有任何链接可以帮助解释这些概念，我会很高兴看到它们！

My understanding of Object Orientated Programming is a little shaky so if you have any links that would help explain the concepts it would be great to see them!

我已经稍微缩短了代码.基本原则是我有一个以主 Controller 类的实例开始的游戏.当游戏打开时，Popup 类被打开.事件发生如下:

I've shortened the code somewhat. The basic principle is that I have a game that starts with an instance of the main Controller class. When the game is opened the Popup class is opened. The events happens as follows:

1. 点击弹窗上的开始按钮
2. 方法 start_click() 运行
3. 调用Controller实例中的start_game()方法
4. 这又将原始控制器实例中的游戏状态更改为真"

我的问题在于第 3 步.我收到的错误消息是:

My problem is with step 3. The error message I get is:

TypeError: unbound method start_game() must be called with Controller 
instance as first argument (got nothing instead)

我想 StartPopUp 类中需要对 Controller 类进行一些引用.但我不太明白如何创建该参考?

I guess there needs to be some reference to the Controller class in the StartPopUp class. But I don't quite understand how to create that reference?

import kivy
kivy.require('1.8.0')

from kivy.app import App
from kivy.uix.widget import Widget
from kivy.clock import Clock
from kivy.properties import BooleanProperty, NumericProperty, ObjectProperty
from kivy.uix.popup import Popup
from kivy.lang import Builder

Builder.load_string('''
<StartPopUp>            
    size_hint: .2, .2
    auto_dismiss: False
    title: 'Welcome'
    Button:
        text: 'Play'
        on_press: root.start_click()
        on_press: root.dismiss()

''')

class StartPopUp(Popup):

    def __init__(self, **kw):
        super(StartPopUp, self).__init__(**kw)

    def start_click(self):
        Controller.start_game()                    

class Controller(Widget):
    playing_label = BooleanProperty(False)          #Intitial phase of game is off

    def __init__(self, **kw):
        super(Controller, self).__init__(**kw)        

    def start_popup(self, dt):    
        sp = StartPopUp()
        sp.open()

    def start_game(self):
        self.playing_label = True
        print self.playing_label   

class MoleHuntApp(App):

    def build(self):
        game = Controller()
        Clock.schedule_once(game.start_popup, 1)
        return game

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

提前致谢！

推荐答案

可以这样传递实例

class StartPopUp(Popup):

    def __init__(self, controller, **kw):
        super(StartPopUp, self).__init__(**kw)
        self.controller = controller

    def start_click(self):
        self.controller.start_game()

在控制器中

def start_popup(self, dt):    
    sp = StartPopUp(self)
    sp.open()

这篇关于从现有实例调用方法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！