Kivymd：如何在不创建自定义类的情况下在列表项中添加复选框？答案

【问题标题】：Kivymd: How to add checkbox in List item without creating custom class?Kivymd：如何在不创建自定义类的情况下在列表项中添加复选框？
【发布时间】：2021-11-22 00:15:43
【问题描述】：

如何添加带有 MDList 项目的复选框？在我的项目中，我需要一个事件，“单击按钮后将所选项目文本存储在 python 列表中”。当我为带有复选框的列表创建自定义类时，可以轻松完成（如 kivymd 文档中所示）。

from kivy.lang import Builder

from kivy.properties import StringProperty
from kivymd.app import MDApp
from kivymd.uix.list import IRightBodyTouch, TwoLineAvatarIconListItem
from kivymd.uix.selectioncontrol import MDCheckbox

KV = """
<ListItemWithCheckbox>:
    IconLeftWidget:
        icon: root.icon
    RightCheckbox:
        id: cb

BoxLayout:

    ScrollView:

        MDList:
            id: scroll
            
    MDRaisedButton:
        text: "Save"
        on_release: app.save_checked()
"""

class ListItemWithCheckbox(TwoLineAvatarIconListItem):
    """Custom list item."""
    icon = StringProperty("android")

class RightCheckbox(IRightBodyTouch, MDCheckbox):
    """Custom right container."""

class MainApp(MDApp):
    def build(self):
        return Builder.load_string(KV)

    def on_start(self):
        for i in range(15):
            self.root.ids.scroll.add_widget(
                ListItemWithCheckbox(text=f"Item {i}", secondary_text=f"Item {i+10}", icon='User_images/s.jpg')
            )
    def save_checked(self):
        mdlist = self.root.ids.scroll  # get reference to the MDList
        selected_item = []
        for wid in mdlist.children:
            if isinstance(wid, ListItemWithCheckbox):  # only interested in the ListItemWithCheckboxes
                cb = wid.ids.cb  # use the id defined in kv
                if cb.active:  # only append selected items

                    selected_item.append(wid.text)
        selected_item = selected_item[::-1]
        print(selected_item)


MainApp().run()

当我尝试使用屏幕管理器（用于处理多个屏幕）应用这个东西时，它不起作用。我可以在不为列表创建自定义类的情况下创建带有复选框的列表吗？

注意：我的要求是，我需要一个带有复选框的列表。按下按钮选择列表项后，应打印所选项目（或用于其他目的）

【问题讨论】：

标签： python list checkbox kivymd

【解决方案1】：

为了在没有自定义类的情况下做到这一点，请使用答案末尾的示例：

from kivy.lang import Builder

from kivy.properties import StringProperty
from kivymd.app import MDApp
from kivymd.uix.list import IRightBodyTouch, TwoLineAvatarIconListItem
from kivymd.uix.selectioncontrol import MDCheckbox

KV = """
<CB@TwoLineAvatarIconListItem>:
    IconLeftWidget:
        id: i1
        icon: "pencil" #root.icon
    IconRightWidget:
        icon: "a11.png" #this is a transparent png image of 188 bytes
        MDCheckbox:
            id: x54
            on_active:
                app.save_checked(*args,root.text,root.secondary_text,root.ids.i1.icon,root)

BoxLayout:
    ScrollView:
        MDList:
            id: scroll
            #for i in range(15)#
            CB:
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
            CB:
                text: "Hello jbsidis"
                secondary_text: "Two"
                icon: "pencil"
            CB:
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
            CB:
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
            CB:
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
            CB:
                text: "Josue Carranza"
                secondary_text: "jbsidis"
                icon: "pencil"
            CB:
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
            CB:
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
            CB:
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
            CB:
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
            CB:
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
            CB:
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
            CB:
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
            CB:
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
            CB:
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
            
    MDRaisedButton:
        id: cm
        text: "Save"
        on_release: app.save_checked()
"""

selected_item = []
class MainAppjbsidis(MDApp):
    def build(self):
        return Builder.load_string(KV)

    def save_checked(self,checkbox, value,a,b,c,w):
        mmm="""
            You clicked on:  Josue Carranza jbsidis
            Selected Items 4: [[<WeakProxy to <kivy.factory.CB object at 0x7efc032f4430>>], [<WeakProxy to <kivy.factory.CB object at 0x7efc032f4430>>], [<WeakProxy to <kivy.factory.CB object at 0x7efc0324d9e0>>], [<WeakProxy to <kivy.factory.CB object at 0x7efc03137b30>>]]
            """
        if value:
            print('The checkbox is active', 'and', checkbox.state, 'state')
            global selected_item
            if len(selected_item)==0:
                selected_item = []
                selected_item.append([w])
                print("\n\nYou clicked on: ",a,b,c)
                print("Selected Items "+str(len(selected_item))+": "+str(selected_item))
            if len(selected_item)>0:
                selected_item.append([w])
                print("\n\nYou clicked on: ",a,b,c)
                print("Selected Items "+str(len(selected_item))+": "+str(selected_item))
                self.root.ids.cm.text="Save "+str(len(selected_item))
        else:
            print('\n\nThe checkbox is inactive', 'and', checkbox.state, 'state')
            new_list=[]
            if len(selected_item)>0:
                for x in selected_item:
                    if x==w:
                        pass
                    if x!=w:
                        new_list=new_list+[w]
                selected_item=new_list
                
                print("\n\nNew Items: "+str(selected_item))
                
MainAppjbsidis().run()

图片：

如果您不想拥有任何自定义类，例如：

<CB@TwoLineAvatarIconListItem>:
    IconLeftWidget:
        id: i1
        icon: "pencil" #root.icon
    IconRightWidget:
        icon: "a11.png" #this is a transparent png image of 188 bytes
        MDCheckbox:
            id: x54
            on_active:
                app.save_checked(*args,root.text,root.secondary_text,root.ids.i1.icon,root)

你应该使用 do it with:

from kivy.lang import Builder

from kivy.properties import StringProperty
from kivymd.app import MDApp
from kivymd.uix.list import IRightBodyTouch, TwoLineAvatarIconListItem
from kivymd.uix.selectioncontrol import MDCheckbox

KV = """
BoxLayout:
    ScrollView:
        MDList:
            id: scroll
            #for i in range(15)#
            TwoLineAvatarIconListItem:
                id: mm1
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
                IconLeftWidget:
                    id: i1
                    icon: "pencil" #root.icon
                IconRightWidget:
                    icon: "a11.png" #this is a transparent png image of 188 bytes
                    MDCheckbox:
                        id: x54
                        on_active:
                            app.save_checked(*args,root.ids.mm1.text,root.ids.mm1.secondary_text,root.ids.i1.icon,root)

            TwoLineAvatarIconListItem:
                id: mm2
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
                IconLeftWidget:
                    id: i1
                    icon: "pencil" #root.icon
                IconRightWidget:
                    icon: "a11.png" #this is a transparent png image of 188 bytes
                    MDCheckbox:
                        id: x54
                        on_active:
                            app.save_checked(*args,root.ids.mm2.text,root.ids.mm2.secondary_text,root.ids.i1.icon,root)

            TwoLineAvatarIconListItem:
                id: mm3
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
                IconLeftWidget:
                    id: i1
                    icon: "pencil" #root.icon
                IconRightWidget:
                    icon: "a11.png" #this is a transparent png image of 188 bytes
                    MDCheckbox:
                        id: x54
                        on_active:
                            app.save_checked(*args,root.ids.mm3.text,root.ids.mm3.secondary_text,root.ids.i1.icon,root)

            TwoLineAvatarIconListItem:
                id: mm4
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
                IconLeftWidget:
                    id: i1
                    icon: "pencil" #root.icon
                IconRightWidget:
                    icon: "a11.png" #this is a transparent png image of 188 bytes
                    MDCheckbox:
                        id: x54
                        on_active:
                            app.save_checked(*args,root.ids.mm4.text,root.ids.mm4.secondary_text,root.ids.i1.icon,root)

            TwoLineAvatarIconListItem:
                id: mm5
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
                IconLeftWidget:
                    id: i1
                    icon: "pencil" #root.icon
                IconRightWidget:
                    icon: "a11.png" #this is a transparent png image of 188 bytes
                    MDCheckbox:
                        id: x54
                        on_active:
                            app.save_checked(*args,root.ids.mm5.text,root.ids.mm5.secondary_text,root.ids.i1.icon,root)

            TwoLineAvatarIconListItem:
                id: mm6
                text: "Hello"
                secondary_text: "Two"
                icon: "pencil"
                IconLeftWidget:
                    id: i1
                    icon: "pencil" #root.icon
                IconRightWidget:
                    icon: "a11.png" #this is a transparent png image of 188 bytes
                    MDCheckbox:
                        id: x54
                        on_active:
                            app.save_checked(*args,root.ids.mm6.text,root.ids.mm6.secondary_text,root.ids.i1.icon,root)

            
    MDRaisedButton:
        id: cm
        text: "Save"
        on_release: app.save_checked()
"""

selected_item = []
class MainAppjbsidis(MDApp):
    def build(self):
        return Builder.load_string(KV)

    def save_checked(self,checkbox, value,a,b,c,w):
        mmm="""
            You clicked on:  Josue Carranza jbsidis
            Selected Items 4: [[<WeakProxy to <kivy.factory.CB object at 0x7efc032f4430>>], [<WeakProxy to <kivy.factory.CB object at 0x7efc032f4430>>], [<WeakProxy to <kivy.factory.CB object at 0x7efc0324d9e0>>], [<WeakProxy to <kivy.factory.CB object at 0x7efc03137b30>>]]
            """
        if value:
            print('The checkbox is active', 'and', checkbox.state, 'state')
            global selected_item
            if len(selected_item)==0:
                selected_item = []
                selected_item.append([w])
                print("\n\nYou clicked on: ",a,b,c)
                print("Selected Items "+str(len(selected_item))+": "+str(selected_item))
            if len(selected_item)>0:
                selected_item.append([w])
                print("\n\nYou clicked on: ",a,b,c)
                print("Selected Items "+str(len(selected_item))+": "+str(selected_item))
                self.root.ids.cm.text="Save "+str(len(selected_item))
        else:
            print('\n\nThe checkbox is inactive', 'and', checkbox.state, 'state')
            new_list=[]
            if len(selected_item)>0:
                for x in selected_item:
                    if x==w:
                        pass
                    if x!=w:
                        new_list=new_list+[w]
                selected_item=new_list
                
                print("\n\nNew Items: "+str(selected_item))
                
MainAppjbsidis().run()

没有客户类的图片：

【讨论】：

编辑：当我输入错误的“客户类”时，我的意思是“自定义类”
谢谢你。但我仍然遇到问题。在实时应用程序中，我需要在 python 文件中创建列表项，然后将所有列表项添加到 .kv 文件中的列表中。你能告诉我解决这个问题的方法吗？注意：尝试在每个列表项中添加复选框时出现错误。
是的，如果您需要将选定的项目移动到新屏幕（到新列表），您应该使用“selected_item”全局变量并将这些选定的项目添加到新的MDList中屏幕，请记住，因为它是一个列表，您可以使用 for 循环将这些选定的项目添加到新屏幕，或者只是将值（而不是现在的小部件）保存为纯文本字符串，然后解析那些在新屏幕中，具体取决于您需要做什么
行 "icon: "a11.png" #this is an transparent png image of 188 bytes" 需要复选框干净并准备好使用，下载一个应该透明的 png 图像
好的，我明白了。如果你能帮助我在这个脚本中实现它，那对我来说会非常好---------> github.com/Shourov1702040/hpylearners_Python/blob/main/…