Kivy复选框性别选择功能失效问题求助

问题根源 #

Kivy原生Checkbox组件不支持单选组特性，直接使用未加逻辑控制的Checkbox会出现多选项可同时选中的问题；若未正确绑定状态变更事件或JSON数据加载逻辑，还会导致复选框无法正常勾选/取消。

以下提供两种可行修复方案，推荐使用第一种（原生组件支持的单选实现）：

方案一：改用ToggleButton实现原生单选（推荐） #

ToggleButton组件原生支持group属性，同一group内的按钮仅能有一个处于选中（down）状态，无需额外逻辑控制。

1. KV文件修正 #

<CharacterCreationScreen>:
    BoxLayout:
        orientation: 'vertical'
        # 性别选择区域
        BoxLayout:
            id: gender_container
            orientation: 'horizontal'
            Label:
                text: '性别:'
            ToggleButton:
                text: '男'
                group: 'gender'
                on_state: root.save_gender(self.text) if self.state == 'down' else None
            ToggleButton:
                text: '女'
                group: 'gender'
                on_state: root.save_gender(self.text) if self.state == 'down' else None
            ToggleButton:
                text: '非二元'
                group: 'gender'
                on_state: root.save_gender(self.text) if self.state == 'down' else None

2. main.py代码修正 #

from kivy.uix.screenmanager import Screen
import json

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

    def load_character_data(self):
        # 从JSON加载角色信息并设置初始选中状态
        try:
            with open('character.json', 'r', encoding='utf-8') as f:
                char_data = json.load(f)
                saved_gender = char_data.get('gender', '')
                if saved_gender:
                    # 遍历性别按钮，匹配已保存的性别并设置选中
                    for btn in self.ids.gender_container.children:
                        if hasattr(btn, 'text') and btn.text == saved_gender:
                            btn.state = 'down'
        except FileNotFoundError:
            # 无文件时初始化空数据
            pass

    def save_gender(self, gender):
        # 将选中的性别保存到JSON文件
        try:
            with open('character.json', 'r', encoding='utf-8') as f:
                char_data = json.load(f)
        except FileNotFoundError:
            char_data = {}
        
        char_data['gender'] = gender
        with open('character.json', 'w', encoding='utf-8') as f:
            json.dump(char_data, f, indent=4, ensure_ascii=False)

方案二：保留Checkbox，手动实现单选逻辑 #

若坚持使用Checkbox，需通过绑定状态变更事件，手动控制同组复选框的选中状态：

1. KV文件修正 #

<CharacterCreationScreen>:
    BoxLayout:
        orientation: 'vertical'
        BoxLayout:
            id: gender_container
            orientation: 'horizontal'
            Label:
                text: '性别:'
            # 男性复选框
            BoxLayout:
                orientation: 'horizontal'
                CheckBox:
                    id: male_check
                    on_active: root.handle_gender_check(self)
                Label:
                    text: '男'
            # 女性复选框
            BoxLayout:
                orientation: 'horizontal'
                CheckBox:
                    id: female_check
                    on_active: root.handle_gender_check(self)
                Label:
                    text: '女'

2. main.py代码修正 #

from kivy.uix.screenmanager import Screen
import json

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

    def load_character_data(self):
        try:
            with open('character.json', 'r', encoding='utf-8') as f:
                char_data = json.load(f)
                saved_gender = char_data.get('gender', '')
                if saved_gender == '男':
                    self.ids.male_check.active = True
                elif saved_gender == '女':
                    self.ids.female_check.active = True
        except FileNotFoundError:
            pass

    def handle_gender_check(self, active_check):
        if active_check.active:
            # 取消其他复选框的选中状态
            if active_check == self.ids.male_check:
                self.ids.female_check.active = False
                self.save_gender('男')
            else:
                self.ids.male_check.active = False
                self.save_gender('女')

    def save_gender(self, gender):
        try:
            with open('character.json', 'r', encoding='utf-8') as f:
                char_data = json.load(f)
        except FileNotFoundError:
            char_data = {}
        
        char_data['gender'] = gender
        with open('character.json', 'w', encoding='utf-8') as f:
            json.dump(char_data, f, indent=4, ensure_ascii=False)

内容的提问来源于stack exchange，提问作者user27988174