如何在kivy recycleview中仅选择一个按钮

我正在使用 kivy recycleview 创建一个 mp3 播放器，该应用程序在播放列表屏幕中有很多按钮，每当您单击某个按钮时，该按钮的图标就会从“播放”更改为“暂停”，反之亦然。

我想知道如何以单击另一个按钮将所有其他按钮图标更改为“播放”的方式，只有选定的按钮应该带有“暂停”图标。

.py 文件：

from kivy.lang import Builder
from kivymd.app import MDApp
from kivy.core.window import Window
from kivy.properties import StringProperty, ObjectProperty
from kivymd.theming import ThemableBehavior
from kivymd.uix.boxlayout import MDBoxLayout
from kivymd.uix.screen import MDScreen
from kivymd.uix.behaviors import RectangularRippleBehavior
from kivy.uix.behaviors import ButtonBehavior

from kivy.clock import Clock

Builder.load_file('playlist.kv')

KV = """
#:import FadeTransition kivy.uix.screenmanager.FadeTransition

ScreenManager:
    transition: FadeTransition()

    Playlist:
        name: "playlist screen"

"""

class Playlist(ThemableBehavior, MDScreen):
    rv = ObjectProperty()
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        Clock.schedule_once(self._finish_init)

    def music_list(self):
        return ['audio '+str(i) for i in range(1, 121)]

    def _finish_init(self, dt):
        self.set_list_musics()
        
    def set_list_musics(self):
        """Builds a list of audios for the screen Playlist."""
        print(self.ids)

        def add_music_item(num, sura, secText, icon):
            self.ids.rv.data.append(
                {
                    "viewclass": "MusicListItem",
                    "number": num,
                    "text": sura,
                    "secondary_text": secText,
                    "icon": icon,
                    "callback": lambda x:x})
    
        for i in range(len(self.music_list())):
            music = self.music_list()
            add_music_item(str(i+1), music[i], '00:00:00', 'play')
         
    
class MusicListItem(ThemableBehavior, RectangularRippleBehavior, ButtonBehavior, MDBoxLayout):
    text = StringProperty()
    secondary_text = StringProperty()
    number = StringProperty()
    icon = StringProperty()
    
    def on_release(self, *args):
        if self.icon == "play":
            self.icon = "pause"
        else:
            self.icon = "play"
    
    
class Mp3Player(MDApp):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
       
    def build(self):
        self.theme_cls.primary_palette = "Purple"
        self.theme_cls.theme_style = "Dark"
        return Builder.load_string(KV)


if '__main__' == __name__:
    Mp3Player().run()

.kv 文件：

#: import gch kivy.utils.get_color_from_hex
#: import StiffScrollEffect kivymd.effects.stiffscroll.StiffScrollEffect

<Playlist>
    md_bg_color: gch("#5D1049")
        
    MDGridLayout:
        cols: 1
        
        MDToolbar:
            left_action_items: [["menu", lambda x: x]]
            right_action_items: [["magnify", lambda x: x]]
            elevation: 10
            md_bg_color: 75/255, 6/255, 54/255, 1
            title: 'Playlist'
            pos_hint: {'top':1}
                    
        MDBoxLayout:
            orientation: 'vertical'
           
            RecycleView:
                id: rv
                effect_cls: 'ScrollEffect'
                viewclass: 'MusicListItem'

                RecycleBoxLayout:
                    padding: dp(10)
                    default_size: None, dp(60)
                    default_size_hint: 1, None
                    size_hint_y: None
                    height: self.minimum_height
                    orientation: 'vertical'

     
<MusicListItem>
    size_hint_y: None
    padding: dp(14)
    height: dp(60)

    canvas:
        Color:
            rgba:
                self.theme_cls.divider_color
        Line:
            points: (root.x+dp(10), root.y, root.x+self.width-dp(10)-0, root.y)

    MDBoxLayout:
        orientation: "horizontal"
        pos_hint: {"center_x": .5, "center_y": .5}

        MDBoxLayout:
            orientation: 'horizontal'
            MDBoxLayout:
                orientation: 'vertical'
                size_hint_x: .2
              
                MDLabel:
                    text: root.number
                    font_style: "H6"
                    adaptive_height: True
                
                MDLabel:
                    size_hint_y: .3
                 
            MDBoxLayout:
                orientation: 'vertical'
             
                MDLabel:
                    text: root.text
                    font_style: "Subtitle2"
                    adaptive_height: True
    
                MDLabel:
                    text: root.secondary_text
                    font_style: "Caption"
                    theme_text_color: "Hint"
                    adaptive_height: True

            MDIconButton:
                icon: root.icon          
    

谢谢

因此，据我了解，您希望将一个图标设置为“暂停”，而将其他图标设置为“播放”。执行此操作的一种方法可能是，您必须重新加载RecyclView data每次图标更改时。

1. 现在提供data通过图标参考（即“播放”或“暂停”）我找到了number属性合适，所以我将其更改为NumericProperty. Thus number = NumericProperty().

2. 这也需要 kv 发生一些变化，

                MDLabel:
                    text: str(int(root.number))
                    font_style: "H6"
                    adaptive_height: True

3. To let Playlist了解有关number参考，

    def set_list_musics(self, music_no = 0):
        """Builds a list of audios for the screen Playlist."""
        print(self.ids)
        self.ids.rv.data = [ ] # Since you are appending data and we need to reload everytime.

4. 进行必要的更改data,

        for i in range(len(self.music_list())):
            new_icon = 'pause' if i+1 == music_no else 'play'
            music = self.music_list()
            add_music_item(str(i+1), music[i], '00:00:00', new_icon)

5. 现在是最后一部分，通过按钮触发更改，

    def on_release(self, *args):
        if self.icon == "play":
            self.icon = "pause"
            pl = self.parent.parent.parent.parent.parent # Accessing the Playlist according to your design pattern.
            pl.set_list_musics(self.number)
        else:
            self.icon = "play"

请注意，我在“暂停”图标中进行了此更改（即在if self.icon == "play"），因此您也可以自由切换该图标。否则放置它就不可能实现。

也许使用其他设计风格可以更系统地完成这一点。我发现您的设计模式存在一些问题。这（例如调用函数for重复循环等）可能会使其慢一些，因为data增加。