AttributeError: 'Screen' object has no attribute 'text' in Python KivyMD

Question

Python 3.9.0

KivyMD 0.104.2.dev0

预期进球

所以我想根据芯片的文本是否存在于名为 list1 的列表中来清除一些 MDChips，但这样做会出现以下错误

问题

当我尝试使用 def clear(self) 函数访问 Widget 树时，我不断收到错误消息，但我不断收到上述错误消息

我发现在下面的 kv 字符串中使用 Screen : 会出现上述错误（在标题中提到）。

button = '''
Screen:
    MDRaisedButton:
        id: button_id
        text: "PRESS ME"
        pos_hint: {"center_x": .35, "center_y": .8}
        on_release: app.drop.open()
'''

但是，如果我删除 Screen :，那么出于某种原因，MDDropDownMenu 小部件在使用 open() 调用时会抛出以下错误：

AttributeError: 'super' object has no attribute '__ getattr __'

代码

from kivy.lang import Builder
from kivymd.uix.screen import Screen
from kivymd.app import MDApp
from kivymd.uix.menu import MDDropdownMenu
from kivymd.uix.chip import MDChip
from kivymd.uix.floatlayout import FloatLayout

button = '''
Screen:
    MDRaisedButton:
        id: button_id
        text: "PRESS ME"
        pos_hint: {"center_x": .35, "center_y": .8}
        on_release: app.drop.open()
'''

button1 = '''
Screen:
    MDRaisedButton:
        id: button1_id
        text: "PRESS ME 2"
        pos_hint: {"center_x": .5, "center_y": .8}
        on_release: app.clear()
'''

list1 = (['Item 1','Item 2','Item 3'], ['Item 4', 'Item 5', 'Item 6'])
class Test(MDApp):
    def build(self):
        self.screen = Screen()
        self.btn = Builder.load_string(button)
        self.btn1 = Builder.load_string(button1)

        self.screen.add_widget(self.btn1)
        self.screen.add_widget(self.btn)


        self.drop = MDDropdownMenu(
            caller = self.btn.ids.button_id,
            items = [{'text':'Show Chips'}],
            width_mult = 4,
        )
        self.drop.bind(on_release=self.testing)

        return self.screen
    
    def testing(self, menu, menu_item):
        objects = {0.2 : "Item 1", 0.5 : "Item 2", 0.8 : "Item 3"}
        for pos, item in objects.items():
            self.chip = MDChip(
                text = item,
                check = True,
                pos_hint = {"center_x":pos, "center_y":0.4},
                
            )
            self.screen.add_widget(self.chip)

    def clear(self):
        for child in self.root.children[:]:
            if child.text in list1[0]:
                self.root.remove_widget(child)

Test().run()

错误

Traceback (most recent call last):
   File "e:\Projects\Workout Planner\Planner v_1\My_Project\Test\test.py", line 61, in <module>
     Test().run()
   File "C:\Users\Mocha\AppData\Local\Programs\Python\Python39\lib\site-packages\kivy\app.py", line 949, in run
     self._run_prepare()
   File "C:\Users\Mocha\AppData\Local\Programs\Python\Python39\lib\site-packages\kivy\app.py", line 919, in _run_prepare
     root = self.build()
   File "e:\Projects\Workout Planner\Planner v_1\My_Project\Test\test.py", line 37, in build
     caller = self.btn.ids.button_id,
   File "kivy\properties.pyx", line 864, in kivy.properties.ObservableDict.__getattr__
 AttributeError: 'super' object has no attribute '__getattr__'
PS E:\Projects\Workout Planner\Planner v_1\My_Project>

Answer 1

虽然我不知道为什么它在我之前发布的代码中不起作用的正确原因，但我已经找到了问题的修复方法

解决方案：

您必须构建另一个继承自 Screen 的 class。然后 enter/copy 您希望在这个新的 Class.

应用程序中拥有的所有内容

并且在继承自 MDApp 的 Class 中您可以指定您想要的主题，并且 return 继承自 Screen[=17] 的 Class =]

此外，在将所有小部件转移到继承自 Screen 的 Class 后，确保将此 class 称为 root 而不是 app您可以将功能绑定到按钮或用它做其他事情。

解决方案代码：

from kivy.lang import Builder
from kivymd.uix.screen import Screen
from kivymd.app import MDApp
from kivymd.uix.menu import MDDropdownMenu
from kivymd.uix.chip import MDChip
from kivymd.uix.floatlayout import FloatLayout

Builder.load_string(
    """
<BuildApp>:

    MDRaisedButton:
        id: button_id
        text: "PRESS ME"
        pos_hint: {"center_x": .35, "center_y": .8}
        on_release: root.drop.open()

    MDRaisedButton:
        id: button1_id
        text: "PRESS ME 2"
        pos_hint: {"center_x": .5, "center_y": .8}
        on_release: root.clear()
        
    """
)#reference should be as root.function_name(),


list1 = (['Item 1','Item 2','Item 3'], ['Item 4', 'Item 5', 'Item 6'])

class BuildApp(Screen):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)

        self.drop = MDDropdownMenu(
            caller = self.ids.button_id,   #use self.id.id_name
            items = [{'text':'Show Chips'}],
            width_mult = 4,
        )
        self.drop.bind(on_release=self.show_chips)
    
    def show_chips(self, menu, menu_item):
        objects = {0.2 : "Item 1", 0.5 : "Item 2", 0.8 : "Item 3"}
        for pos, item in objects.items():
            self.chip = MDChip(
                text = item,
                check = True,
                pos_hint = {"center_x":pos, "center_y":0.4},
                
            )
            self.add_widget(self.chip)

    def clear(self):
        for child in self.children[:]:
            if child.text in list1[0]:
                self.remove_widget(child)

class Test(MDApp):
    def build(self):
        return BuildApp()

    
    

Test().run()

Reference

AttributeError: 'Screen' object has no attribute 'text' in Python KivyMD