Kivy MD技术疑问：如何获取uix.list/OneLineAvatarIconListItem的选中项

要实现获取带复选框列表的选中项，你可以通过以下步骤修改代码：

1. 给列表项关联设备数据并绑定复选框事件 #

修改ListItemWithCheckbox类，添加device属性存储对应设备信息，同时在KV语言中给复选框绑定状态变化事件，触发列表项的处理逻辑：

class ListItemWithCheckbox(OneLineAvatarIconListItem):
    device = None  # 存储对应设备数据

    def on_checkbox_active(self, checkbox, value):
        # 当复选框状态变化时，调用View的方法更新选中列表
        self.parent.parent.parent.update_selected_devices(self.device, value)

同时更新KV字符串里的ListItemWithCheckbox规则，给RightCheckbox绑定on_active事件：

<ListItemWithCheckbox>:
    RightCheckbox:
        on_active: root.on_checkbox_active(self, self.active)

2. 在View类中维护选中设备列表并实现更新方法 #

在View类中添加selected_devices列表存储选中的设备，同时实现update_selected_devices方法来更新这个列表，再添加一个get_selected_devices方法返回选中项：

class View(MDFloatLayout): 
    detectedDevices = list()
    for i in range(20):
        device = dict(name='DEVICE ' + str(i), index=i+1, battery_level=np.random.randint(low=0, high=101))
        detectedDevices.append(device)
    
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.selected_devices = []  # 初始化选中设备列表
        for device in self.detectedDevices:
            list_item = ListItemWithCheckbox(text=device['name'])
            list_item.device = device  # 给列表项绑定设备数据
            self.ids.scroll.add_widget(list_item)
    
    def update_selected_devices(self, device, is_selected):
        if is_selected:
            if device not in self.selected_devices:
                self.selected_devices.append(device)
        else:
            if device in self.selected_devices:
                self.selected_devices.remove(device)
    
    def get_selected_devices(self):
        # 返回所有选中的设备
        return self.selected_devices

3. 添加测试按钮（可选） #

如果需要直观查看选中项，可以在View的KV布局里添加一个按钮，绑定触发显示选中项的方法：

更新KV字符串：

<View>:
    MDFloatLayout:
        MDScrollView:
            pos_hint: {"top": 0.9}
            size_hint_y: 0.9
            MDList:
                id: scroll
        MDRaisedButton:
            text: "查看选中项"
            pos_hint: {"center_x": 0.5, "y": 0.05}
            on_press: root.show_selected_devices()

然后在View类中添加show_selected_devices方法：

def show_selected_devices(self):
    selected = self.get_selected_devices()
    if selected:
        names = [dev['name'] for dev in selected]
        toast(f"选中设备：{', '.join(names)}")
    else:
        toast("未选中任何设备")

完整修改后的代码 #

from kivy.lang import Builder
from kivymd.app import MDApp
from kivymd.uix.floatlayout import MDFloatLayout
from kivymd.uix.list import IRightBodyTouch, OneLineAvatarIconListItem
from kivymd.uix.selectioncontrol import MDCheckbox
from kivymd.toast import toast
import numpy as np


Builder.load_string(
    """    
<ListItemWithCheckbox>:
    RightCheckbox:
        on_active: root.on_checkbox_active(self, self.active)
       
<View>:
    MDFloatLayout:
        MDScrollView:
            pos_hint: {"top": 0.9}
            size_hint_y: 0.9
            MDList:
                id: scroll
        MDRaisedButton:
            text: "查看选中项"
            pos_hint: {"center_x": 0.5, "y": 0.05}
            on_press: root.show_selected_devices()
"""
)
    

class ListItemWithCheckbox(OneLineAvatarIconListItem):
    device = None

    def on_checkbox_active(self, checkbox, value):
        self.parent.parent.parent.update_selected_devices(self.device, value)


class RightCheckbox(IRightBodyTouch, MDCheckbox):
    pass

    

class View(MDFloatLayout): 
    detectedDevices = list()
    for i in range(20):
        device = dict(name='DEVICE ' + str(i), index=i+1, battery_level=np.random.randint(low=0, high=101))
        detectedDevices.append(device)
    
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.selected_devices = []
        for device in self.detectedDevices:
            list_item = ListItemWithCheckbox(text=device['name'])
            list_item.device = device
            self.ids.scroll.add_widget(list_item)
    
    def update_selected_devices(self, device, is_selected):
        if is_selected:
            if device not in self.selected_devices:
                self.selected_devices.append(device)
        else:
            if device in self.selected_devices:
                self.selected_devices.remove(device)
    
    def get_selected_devices(self):
        return self.selected_devices
    
    def show_selected_devices(self):
        selected = self.get_selected_devices()
        if selected:
            names = [dev['name'] for dev in selected]
            toast(f"选中设备：{', '.join(names)}")
        else:
            toast("未选中任何设备")
    
  
class MainApp(MDApp):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.view = View()
        

    def build(self):
        self.title = 'KivyMD选中项示例'
        return self.view
  

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

关键说明 #

• 每个ListItemWithCheckbox实例都绑定了对应的device字典，确保复选框状态变化时能关联到具体设备
• update_selected_devices方法负责维护选中设备列表，避免重复添加或遗漏移除
• 通过get_selected_devices可以随时获取当前所有选中的设备数据，用于后续业务逻辑处理

内容的提问来源于stack exchange，提问作者eljamba