Question

基本上，我有一个带正方形的网格，我跟踪每个正方形上布满了BooleanProperty的正方形。这是我的代码中所有地方的简化版本我宣布＆＃34;占用＆＃34;属性：

class Board(GridLayout):
    def __init__(self):
        super().__init__()
        self.cols = 4
        self.grid = []
        self.create_slots()




    def create_slots(self):
        for i in range(10):
            self.grid.append([])
            for j in range(4):
                temp = Square(i,j, "sideboard")
                self.grid[i].append(temp)
                self.add_widget(temp)
                temp.bind(on_occupied = self.do_a_thing)


    def do_a_thing(self):
        for square in self.children:
            #do a thing

class Square(Button):
    def __init__(self, row, col, type):
        self.row = row
        self.col = col
        self.id = str(self.row) + "," + str(self.col)
        self.type = type
        self.occupied = BooleanProperty(False)
        super().__init__()

我的目标是绑定＆＃34; do_a_thing＆＃34;每次广场的价值被占用时被调用的方法＆＃34;财产变化。因为Square类在我的应用程序的其他地方使用，我不想在kivy语言中为on_occupied设置回调，我希望避免创建一个Square子类来改变一个绑定。

当我运行我的代码时，它不会抛出任何错误，并且我已经验证了＆＃34;占用了＆＃34;财产确实改变了。但是＆＃34; do_a_thing＆＃34;方法永远不会被解雇。谁能告诉我我做错了什么？

Answer 1

请注意，对于属性my_property，更改事件也称为my_property。回调收到两个参数：instance that fired the event, and new value of the property，如the docs所示。此外，如果该类具有名为on_ propertyname 的方法，则也会调用此方法。这是一个适合我的自包含示例：

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.gridlayout import GridLayout
from kivy.uix.button import Button
from kivy.properties import BooleanProperty

class Board(GridLayout):
    def __init__(self, **kwargs):
        super(Board, self).__init__(**kwargs)
        for i in range(10):
            self.add_widget(Square())
        for square in self.children:
            print square
            square.bind(occupied=self.do_a_thing)

    def do_a_thing(self, *args):
        print "hello from {}, new state: {}".format(*args)
        for square in self.children:
            pass
            #do a thing

class Square(Button):
     occupied = BooleanProperty(False)
     def on_occupied(self, *args):
         print "Callback defined in class: from {} state {}".format(*args)


class mApp(App):
    def build(self):
        return Builder.load_string("""
Board:
    cols: 4
    rows: 3
<Square>:
    on_press: self.occupied = ~self.occupied
""")
mApp().run()

Kivy绑定到on_property似乎不起作用

1 个答案: