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删除列表项错误

发布于 2025-01-11 16:59:31 字数 6090 浏览 0 评论 0原文

我是 Python 新手，我创建了一个带有回收视图的简单应用程序。它有 2 个按钮，分别是添加项目和删除项目。当单击添加或删除项目按钮时，应用程序将在回收视图中更新。它还包含预加载到回收视图中的项目列表。

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.recycleview import RecycleView
from kivy.lang import Builder
from kivy.properties import ObjectProperty
from kivy.core.window import Window
from functools import partial

Window.size = (350, 600)

Builder.load_string('''
<RootWidget>:

    inputbutton   : inputbutton
    inputbutton2   : inputbutton2
    inputcontent  : inputcontent
    outputcontent : outputcontent

    BoxLayout:
        orientation: "vertical"
        size_hint : 1, .9
        spacing: 10
        padding: 20

        Label : 
            text :'Favourite Pizza'
            size_hint : 1, .2
            font_size : 30
            color : 0,0,0,1

        TextInput :
            id : inputcontent
            font_size: 25
            focus: True
            multiline : False
            size_hint : .8, .15 
            pos_hint : {'x': .1, 'y': .8}

        Button :
            id : inputbutton
            size_hint : .8, .1
            pos_hint : {'x': .1, 'y': .8}
            text : 'Add Item '
            on_press : root.add_item()

        Button :
            id : inputbutton2
            size_hint : .8, .1
            pos_hint : {'x': .1, 'y': .8}
            text : 'Delete Item '
            on_press : root.delete_item()

        ListWidget:
            viewclass: 'Label'  
            orientation : 'vertical'
            id : outputcontent
            
            RecycleBoxLayout:      
                default_size: None, 30
                default_size_hint: 1, None
                size_hint_y: None
                height: self.minimum_height
                orientation : 'vertical'          
''') 
      
class ListWidget(RecycleView):   
             
    def __init__(self, **kwargs): 
        super().__init__(**kwargs)  
        self.items = ["Pepperoni", "Cheese","Papper", "Hawaii", "Seafood", "Ham", "Taco", "Onion"] 
        self.data = [{'text': str(item)} for item in self.items]

    def update(self):                  
        self.data = [{'text': str(item)} for item in self.items]
         
class RootWidget(BoxLayout):
    inputbutton   = ObjectProperty(None)  
    inputbutton2  = ObjectProperty(None)
    inputcontent  = ObjectProperty(None)  
    outputcontent = ObjectProperty(None)

    def delete_item(self):
         if self.inputcontent.text != '': 
            self.outputcontent.items.remove(self.inputcontent.text)
            self.outputcontent.update()
            self.inputcontent.text = ''

    def add_item(self):                     
        if self.inputcontent.text != '': 
            formatted = f'\n {self.inputcontent.text}'
            self.outputcontent.items.append(formatted)
            self.outputcontent.update()
            self.inputcontent.text = ''    
    
class MainApp(App): 
    title='Search App'
    def build(self):
        Window.clearcolor = (51/255, 153/255, 1, 1) 
        return RootWidget()  
   
MainApp().run()

当我输入一个Apple并单击添加项目按钮时，它将被添加到回收视图中，但是，当我输入一个Apple并单击删除时，会发生以下错误。如何解决呢？

Traceback (most recent call last):
   File "c:\Users\Kelvin Loh\Documents\kivygui\app\add_delete.py", line 105, in <module>
     MainApp().run()
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\app.py", line 950, in run
     runTouchApp()
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\base.py", line 582, in runTouchApp
     EventLoop.mainloop()
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\base.py", line 347, in mainloop
     self.idle()
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\base.py", line 391, in idle
     self.dispatch_input()
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\base.py", line 342, in dispatch_input
     post_dispatch_input(*pop(0))
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\base.py", line 248, in post_dispatch_input
     listener.dispatch('on_motion', etype, me)
   File "kivy\_event.pyx", line 709, in kivy._event.EventDispatcher.dispatch
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\core\window\__init__.py", line 1412, in on_motion
     self.dispatch('on_touch_down', me)
   File "kivy\_event.pyx", line 709, in kivy._event.EventDispatcher.dispatch
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\core\window\__init__.py", line 1428, in on_touch_down
     if w.dispatch('on_touch_down', touch):
   File "kivy\_event.pyx", line 709, in kivy._event.EventDispatcher.dispatch
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\uix\widget.py", line 545, in on_touch_down
     if child.dispatch('on_touch_down', touch):
   File "kivy\_event.pyx", line 709, in kivy._event.EventDispatcher.dispatch
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\uix\widget.py", line 545, in on_touch_down
     if child.dispatch('on_touch_down', touch):
   File "kivy\_event.pyx", line 709, in kivy._event.EventDispatcher.dispatch
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\uix\behaviors\button.py", line 151, in on_touch_down
     self.dispatch('on_press')
   File "kivy\_event.pyx", line 705, in kivy._event.EventDispatcher.dispatch
   File "kivy\_event.pyx", line 1248, in kivy._event.EventObservers.dispatch
   File "kivy\_event.pyx", line 1132, in kivy._event.EventObservers._dispatch
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\lang\builder.py", line 57, in custom_callback
     exec(__kvlang__.co_value, idmap)
   File "<string>", line 41, in <module>
   File "c:\Users\Kelvin Loh\Documents\kivygui\app\add_delete.py", line 84, in delete_item
     self.outputcontent.items.remove(self.inputcontent.text)
 ValueError: list.remove(x): x not in list
原文

I am new to Python and I have created a simple app with a Recycle view. It has 2 buttons which are adding an item and deleting an item. When the click the added or deleted item button, the app will be updated in the Recycle View. It also contains a list of the item that is preloaded into the recycle view.

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.recycleview import RecycleView
from kivy.lang import Builder
from kivy.properties import ObjectProperty
from kivy.core.window import Window
from functools import partial

Window.size = (350, 600)

Builder.load_string('''
<RootWidget>:

    inputbutton   : inputbutton
    inputbutton2   : inputbutton2
    inputcontent  : inputcontent
    outputcontent : outputcontent

    BoxLayout:
        orientation: "vertical"
        size_hint : 1, .9
        spacing: 10
        padding: 20

        Label : 
            text :'Favourite Pizza'
            size_hint : 1, .2
            font_size : 30
            color : 0,0,0,1

        TextInput :
            id : inputcontent
            font_size: 25
            focus: True
            multiline : False
            size_hint : .8, .15 
            pos_hint : {'x': .1, 'y': .8}

        Button :
            id : inputbutton
            size_hint : .8, .1
            pos_hint : {'x': .1, 'y': .8}
            text : 'Add Item '
            on_press : root.add_item()

        Button :
            id : inputbutton2
            size_hint : .8, .1
            pos_hint : {'x': .1, 'y': .8}
            text : 'Delete Item '
            on_press : root.delete_item()

        ListWidget:
            viewclass: 'Label'  
            orientation : 'vertical'
            id : outputcontent
            
            RecycleBoxLayout:      
                default_size: None, 30
                default_size_hint: 1, None
                size_hint_y: None
                height: self.minimum_height
                orientation : 'vertical'          
''') 
      
class ListWidget(RecycleView):   
             
    def __init__(self, **kwargs): 
        super().__init__(**kwargs)  
        self.items = ["Pepperoni", "Cheese","Papper", "Hawaii", "Seafood", "Ham", "Taco", "Onion"] 
        self.data = [{'text': str(item)} for item in self.items]

    def update(self):                  
        self.data = [{'text': str(item)} for item in self.items]
         
class RootWidget(BoxLayout):
    inputbutton   = ObjectProperty(None)  
    inputbutton2  = ObjectProperty(None)
    inputcontent  = ObjectProperty(None)  
    outputcontent = ObjectProperty(None)

    def delete_item(self):
         if self.inputcontent.text != '': 
            self.outputcontent.items.remove(self.inputcontent.text)
            self.outputcontent.update()
            self.inputcontent.text = ''

    def add_item(self):                     
        if self.inputcontent.text != '': 
            formatted = f'\n {self.inputcontent.text}'
            self.outputcontent.items.append(formatted)
            self.outputcontent.update()
            self.inputcontent.text = ''    
    
class MainApp(App): 
    title='Search App'
    def build(self):
        Window.clearcolor = (51/255, 153/255, 1, 1) 
        return RootWidget()  
   
MainApp().run()

When I have typed an Apple and click add item button, it will be added in the Recycle View, however, when I type an Apple and click delete, the following error was incurred. How to resolve it?

Traceback (most recent call last):
   File "c:\Users\Kelvin Loh\Documents\kivygui\app\add_delete.py", line 105, in <module>
     MainApp().run()
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\app.py", line 950, in run
     runTouchApp()
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\base.py", line 582, in runTouchApp
     EventLoop.mainloop()
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\base.py", line 347, in mainloop
     self.idle()
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\base.py", line 391, in idle
     self.dispatch_input()
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\base.py", line 342, in dispatch_input
     post_dispatch_input(*pop(0))
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\base.py", line 248, in post_dispatch_input
     listener.dispatch('on_motion', etype, me)
   File "kivy\_event.pyx", line 709, in kivy._event.EventDispatcher.dispatch
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\core\window\__init__.py", line 1412, in on_motion
     self.dispatch('on_touch_down', me)
   File "kivy\_event.pyx", line 709, in kivy._event.EventDispatcher.dispatch
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\core\window\__init__.py", line 1428, in on_touch_down
     if w.dispatch('on_touch_down', touch):
   File "kivy\_event.pyx", line 709, in kivy._event.EventDispatcher.dispatch
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\uix\widget.py", line 545, in on_touch_down
     if child.dispatch('on_touch_down', touch):
   File "kivy\_event.pyx", line 709, in kivy._event.EventDispatcher.dispatch
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\uix\widget.py", line 545, in on_touch_down
     if child.dispatch('on_touch_down', touch):
   File "kivy\_event.pyx", line 709, in kivy._event.EventDispatcher.dispatch
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\uix\behaviors\button.py", line 151, in on_touch_down
     self.dispatch('on_press')
   File "kivy\_event.pyx", line 705, in kivy._event.EventDispatcher.dispatch
   File "kivy\_event.pyx", line 1248, in kivy._event.EventObservers.dispatch
   File "kivy\_event.pyx", line 1132, in kivy._event.EventObservers._dispatch
   File "C:\Users\Kelvin Loh\Documents\kivygui\kivy_venv\lib\site-packages\kivy\lang\builder.py", line 57, in custom_callback
     exec(__kvlang__.co_value, idmap)
   File "<string>", line 41, in <module>
   File "c:\Users\Kelvin Loh\Documents\kivygui\app\add_delete.py", line 84, in delete_item
     self.outputcontent.items.remove(self.inputcontent.text)
 ValueError: list.remove(x): x not in list

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东北女汉子 2025-01-18 16:59:31

如果您修改 delete_item() 代码以打印正在发生的情况，如下所示：

def delete_item(self):
    print('items:', self.outputcontent.items)
    print('trying to delete:', self.inputcontent.text)
    if self.inputcontent.text != '':
        self.outputcontent.items.remove(self.inputcontent.text)
        self.outputcontent.update()
        self.inputcontent.text = ''

您将看到您正在尝试删除不在 items 列表中的内容，因为您在文本前面添加了 \n 。解决方法是始终仅使用文本添加到 itmes（或者可能使用 strip()）。这是 add_item() 方法的修改版本，可修复该问题：

def add_item(self):
    if self.inputcontent.text != '':
        self.outputcontent.items.append(self.inputcontent.text.strip())
        self.outputcontent.update()
        self.inputcontent.text = ''

If you modify your delete_item() code to print what is going on, like this:

def delete_item(self):
    print('items:', self.outputcontent.items)
    print('trying to delete:', self.inputcontent.text)
    if self.inputcontent.text != '':
        self.outputcontent.items.remove(self.inputcontent.text)
        self.outputcontent.update()
        self.inputcontent.text = ''

You will see that you are trying to delete something that is not in the items list, because you are prepending a \n to the text. The fix is to always use just the text to add to the itmes (or perhaps use strip()). Here is a modified version of your add_item() method that fixes the problem:

def add_item(self):
    if self.inputcontent.text != '':
        self.outputcontent.items.append(self.inputcontent.text.strip())
        self.outputcontent.update()
        self.inputcontent.text = ''
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