GUI生成后，如何在kivy中创建带有参数的按钮循环？

Question

我对 Kivy-Libaray 有疑问。我目前正在为 ShoppinglistApp 编写前端。我有一个主菜单，您可以在其中选择您想要做的事情（添加列表/商店），您可以从那里进入商店选择。

1. 在商店选择菜单中有 4 家商店。
2. 所有项目（产品）都存储在一个列表中。
3. 如果您选择商店，则应为每个商品（来自该商店）创建一个按钮。

我厌倦了这个解决方案：

       

    from kivy.app import App
    from kivy.metrics import dp
    from kivy.lang import Builder
    from kivy.properties import StringProperty
    from kivy.uix.stacklayout import StackLayout
    from kivy.uix.boxlayout import BoxLayout
    from kivy.uix.button import Button
    from kivy.uix.screenmanager import ScreenManager, Screen
    
    
    
    # the rest
    class Produkt:
        def __init__(self, name, amount, market):
            self.name = name
            self.amount = amount
            self.market = market
    
    
    eklist = []
    for i in range(0, 100):
        nn = "Banane" + str(i)
        eklist.append(Produkt(nn, 0, "Baumarkt"))
    
    
    # Define Screens
    
    class FirstWindow(Screen):
        pass
    
    
    class SecondWindow(Screen):
        pass
    
    
    class ThirdWindow(Screen):
        pass
    
    
    class WindowManager(ScreenManager):
        pass
    
    
    """Anfang der Chose"""
    
    
    class Box(BoxLayout):
        pass
    
    # Gvar is a class I created for the purpose of transporting variable(s). Especially the selected shop.
    
    class Gvar:
        def __init__(self, var1):
            self.var1 = var1
    
        def get(self):
            return self.var1
    
    gvar = Gvar("default")
    
    
    # SetBox ist the Class for changing the variable through the shop selection menu.
    class SetBox(BoxLayout):
    
        def set(self, market):
            gvar.var1 = market
            print("Set")
            print(gvar.var1)
    
    
    class BLE(BoxLayout):
        pass
    
    
    # This is the Menus which makes Problems.
    class SLE(StackLayout):
    
        def __init__(self, **kwargs):
            super().__init__(**kwargs)
    
            for p in eklist:
                # In theory, this if request should always be triggerd. In praxis, I made the else Request to debug.
                # for Text normally would appear p.name, but I changed it for debugging. Text shown(gvar.var1) is "default".
                if p.market == str(gvar.get()):
                    b = Button(text=str(gvar.get()), size_hint=(None, None), color="blue", size=(dp(200), dp(100)),
                               on_press=lambda *args: self.test1(*args, str(p.name)))
                    b.prod = p
                    self.add_widget(b)
    
                else:
                    b = Button(text=str(gvar.get()), size_hint=(None, None), color="green", size=(dp(200), dp(100)),
                               on_press=lambda *args: self.test1(*args, str(p.name)))
                    b.prod = p
                    self.add_widget(b)
        market = None
    
    # test 1 is a placeholder for a Backend funktion
    # Here I print the Produkt and gvar.var1, to debug. Here it get for gvar.var1 the in the GUI selected Value.
        def test1(self, b, i):
            print("Initialize test2, please wait...")
            print(b.prod.name, b.prod.amount, b.prod.market, gvar.var1)
    
    
    """Ende der Chose"""
    
    kv = Builder.load_file('einkaufsliste.kv')
    
    
    class EinkaufsApp(App):
        def build(self):
            return kv
    
    
    if __name__ == '__main__':
        EinkaufsApp().run()
    

+

这是 Kivy 文件。

WindowManager:
FirstWindow:
SecondWindow:
ThirdWindow:
&ltFirstWindow&gt:
    name: "first"

    Box:
        orientation: "vertical"
        size :root.width, root.height

        Label:
            text: "Hauptmenü"
            size_hint: 1, .2
            font_size: 32


        Button:
            text: "Einkaufen"
            font_size: 32
            background_normal: ' '
            background_color: "#666e00"
            on_release:
                app.root.current = "third"
                root.manager.transition.direction = "left"

        Button:
            text: "Einkaufsliste updaten"
            font_size: 32
            background_normal: ' '
            background_color: "#660000"
            on_release:
                app.root.current = "second"
                root.manager.transition.direction = "left"



&ltSecondWindow&gt:
    name: "second"

    BLE:
        id: BLE
        orientation: "vertical"
        Button:
            text: "to first"
            size_hint: 1, .1
            font_size: 24
            on_release:
                app.root.current = "first"
                root.manager.transition.direction = "right"
        TextInput:
            multiline: False
            size_hint: 1, .1
        SVE:


&ltThirdWindow&gt:
    name: "third"

    SetBox:
        orientation: "vertical"
        size :root.width, root.height
        id:SetBox

        Box:
            orientation: "horizontal"
            size_hint: 1, .4
            Button:
                text: "to first"
                size_hint: .2, 1
                font_size: 24
                on_release:
                    app.root.current = "first"
                    root.manager.transition.direction = "right"


            Label:
                text: "Markt auswählen"
                size_hint: .8, 1
                font_size: 32



        Button:
            text: "Supermarkt"
            font_size: 32
            background_normal: ' '
            background_color: "#a1b2e3"
            on_release:
                app.root.current = "second"
                root.manager.transition.direction = "left"
            on_press: SetBox.set("Supermarkt")

        Button:
            text: "Drogerie"
            font_size: 32
            background_normal: ' '
            background_color: "#c7bbc9"
            on_release:
                app.root.current = "second"
                root.manager.transition.direction = "left"
            on_press: SetBox.set("Drogerie")

        Button:
            text: "Baumarkt"
            font_size: 32
            background_normal: ' '
            background_color: "#b4eeb4"
            on_release:
                app.root.current = "second"
                root.manager.transition.direction = "left"
            on_press: SetBox.set("Baumarkt")

        Button:
            text: "Elektrogerätefachhandel"
            font_size: 32
            background_normal: ' '
            background_color: "#f4c2c2"
            on_release:
                app.root.current = "second"
                root.manager.transition.direction = "left"
            on_press: SetBox.set("Elektrogerätefachhandel")


&ltSVE@ScrollView&gt:
    SLE:
        id: Scrollwin
        size_hint: 1, None
        height: self.minimum_height

&ltSLE&gt:
    # orientation: "rl-bt"
    # spacing: "1dp", "1dp"

</code></pre>    

我认为问题在于，kivy 在我更改变量之前创建了整个 GUI。 有没有办法重新加载屏幕或者我必须为每个市场/商店制作另一个屏幕？

Answer 1

您可以随心所欲。您必须将项目添加到相应的布局中。我举一个我前段时间做的项目的例子：

class ExmapleApp(App):
    def build(self):
        #Create GridLayout where you will add and remove widgets
        self.gridRooms = gridRooms = GridLayout(cols=10, padding=10, spacing=10,
                                    row_force_default=True, row_default_height=50, size_hint_y=None)
        gridRooms.bind(minimum_height=gridRooms.setter('height'))

        # Generate 10 Rooms items
        for i in range(10):
            labl = NewLabel() #Instace of NewLabel
            labl.num = str(i+1) #Number of room
            labl.roomName = "Room "+str(labl.num) # Room name
            labl.filename = '12916_sweet_trip_mm_kwik_mod_01.wav'
            roomsList.append(labl) #This add the room to a list for further reference
            gridRooms.add_widget(labl) #This add the rooms to a grid

这是到目前为止的样子：

最后，您可以将小部件添加到该 GridLayout：

        #Create the object you want to Add
        labl = NewLabel() #Instace of NewLabel
        labl.num = str(11) #Number of room
        labl.roomName = "Room "+str(labl.num) # Room name
        labl.filename = '12916_sweet_trip_mm_kwik_mod_01.wav'
        roomsList.append(labl) #This add the room to a list for further reference

        #This add the widgets 3 secs after the program starts
        Clock.schedule_once(lambda x: gridRooms.add_widget(roomsList[10]), 3) #Add room 11

您甚至可以在每次按下按钮时进行回调以创建新的小部件。 要删除一个小部件：

gridRooms.remove_widget(roomsList[10]) #Removes Room 11