Kivy - 将结构解析为小部件

Question

我在将数据结构解析为 Kivy 中的小部件时遇到问题，该小部件将访问该结构并能够在屏幕上显示一个值，并通过时钟间隔不断更新（不确定更好的做法这还没有）。

我在下面的（非工作）代码中突出显示了问题：

ma​​in.py

from kivy.app import App
from test import TestWidget

class TestApp(App):

    def build(self):
        testStructTable = {'randomVal1': 1, 'testVal': 2, 'randomVal2': 3}

        # Issue here parsing the table like this?
        return TestWidget(testStructTable)

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

test.py

from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.relativelayout import RelativeLayout
from kivy.properties import NumericProperty


class TestWidget(RelativeLayout):

    def __init__(self, testStructTable, **kwargs):
        super(TestWidget, self).__init__(**kwargs)
        Builder.load_file('test.kv')

        sm = ScreenManager()
        sm.add_widget(MainScreen(name='MainScreen'))
        self.add_widget(sm)

        # Error accessing the table
        print self.testStructTable

        # Have the update_test_val continuously called
        #Clock.schedule_interval(MainScreen.update_test_val(testStructTable), 1 / 60)


class MainScreen(Screen):

    def __init__(self, **kwargs):
        testVal = NumericProperty(0)

    def update_test_val(self, testStructTable):
        # Get testVal from testStructTable
        # Something like:
        # self.testVal = testStructTable.testVal + 1 ?
        self.testVal = self.testVal + 1

test.kv

<MainScreen>:
    FloatLayout:
        Label:
            text: str(root.testVal)
            font_size: 80

我的目标是通过访问该数据结构让 testVal 在屏幕上不断更新，但是我目前无法实现这一点，您能否建议？

Answer 1

在您的__init__ 方法中，您传递了testStructTable，然后您尝试访问self.testStructTable，在您明确分配之前不存在：

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.relativelayout import RelativeLayout
from kivy.properties import NumericProperty


class TestWidget(RelativeLayout):
    def __init__(self, testStructTable, **kwargs):
        super(TestWidget, self).__init__(**kwargs)

        print(testStructTable)
        self.testStructTable = testStructTable
        print(self.testStructTable)


class TestApp(App):
    def build(self):
        testStructTable = {'randomVal1': 1, 'testVal': 2, 'randomVal2': 3}
        # Issue here parsing the table like this?
        return TestWidget(testStructTable)

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