KIVY：按下按钮时在子布局中添加按钮（on_release）

Question

屏幕有多个布局，都是盒子布局的子布局。当单击其他布局中的按钮时，我试图在最后一个子布局（网格布局）中添加一个按钮。代码不会崩溃，但也没有任何反应。我想在单击按钮时将按钮添加到带有 id 饮料布局的布局中，例如百事可乐、精灵

Python：

class MainScreen(Screen):
    pass

class AnotherScreen(Screen):
    pass

class ScreenManagement(ScreenManager):
    pass
class Stacks(StackLayout):
    pass


present=Builder.load_file('hellokivy2.kv')  #Specifying location of kv file     

class MainApp(App):

    def build(self):
        return present
    def drinksSelect(self,value): #creating a button by referring the id of the layout in which to create button
        print(value)
        yolo = AnotherScreen()
        yolo2 = yolo.ids.newButtonLayout
        button = Button(text="value",size_hint= (0.2,0.4))
        yolo2.add_widget(button)


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

KV

#: import FadeTransition kivy.uix.screenmanager.FadeTransition

ScreenManagement:
    transition: FadeTransition()
    MainScreen:
    AnotherScreen:

<MainScreen>:
name: "main"

canvas.before:
    Color:
        rgba: 1, 1, 1, 1
    Rectangle:
        pos: self.pos
        size: self.size

BoxLayout:

    orientation: 'vertical'
    size:root.size

    Button:
        text: "Slideshow"

    GridLayout:

        cols: 2

        Button:
            text: "Burger"


        Button:
            text: "Drinks"
            on_release: app.root.current = "other"

        Button:
            text: "Fries"

        Button:
            text: "Others"
    Label:
        text: "Your Cart"
        font_size: 40
        color:(0,0,0,1)
        size_hint_y: None
        canvas.before:
            Color:
                rgba:150,10,200,0.5
            Rectangle:
                pos: self.pos
                size: self.size
<AnotherScreen>:
    name: "other"
    canvas.before:
        Color:
            rgba: 1, 1, 1, 1
        Rectangle:
            pos: self.pos
            size: self.size

BoxLayout:
    size:root.size
    orientation: 'vertical'
    GridLayout:
        size_hint_y:0.1
        orientation: 'vertical'
        rows: 1
        Button:
            color: 1,1,1,1
            font_size: 25
            size_hint_y:0.1
            text: "Back Home"
            on_release: app.root.current = "main"
        Label:
            text: "Project BAM"
            canvas.before:
                Color:
                    rgba: 0,0,0,1
                Rectangle:
                    pos: self.pos
                    size: self.size
        Button:
            color: 1,1,1,1
            font_size: 25
            size_hint_y:0.1
            text: "Profile"
            on_release: app.root.current = "main"
    Button:
        color: 1,1,1,1
        font_size: 25
        size_hint_y:0.9
        text: "Whats New"
        on_release: app.root.current = "main"

    GridLayout:
        rows: 2
        Button:
            text: "Pepsi"
            on_release: app.drinksSelect(1)

        Button:
            text: "7up"
            on_release: app.drinksSelect(2)
        Button:
            text: "Fanta"
            on_release: app.drinksSelect(3)
        Button:
            text: "Mountain Dew"
            on_release: app.drinksSelect(4)
        Button:
            text: "Diet Pepsi"
            on_release: app.drinksSelect(5)
        Button:
            text: "Sprite"
            on_release: app.drinksSelect(6)

    GridLayout:
        id: drinksLayout
        size_hint_y: 0.3
        orientation: 'horizontal'
        rows: 1

        Button:
            id: label1
            size_hint: 0.2,0.4
            background_normal:'1.jpg'
            text: 'B1'
        Button:
            id: label2
            size_hint: 0.2,0.4
            background_normal:'1.jpg'
            text: 'B1'
        Button:
            id: label3
            size_hint: 0.2,0.4
            background_normal:'1.jpg'
            text: 'B1'

Answer 1

好的，问题是你的drinksSelect 方法，你还需要保持屏幕的价值

试试这个：

py：

from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.lang.builder import Builder
from kivy.uix.stacklayout import StackLayout
from kivy.uix.button import Button
from kivy.properties import ObjectProperty


class MainScreen(Screen):
    pass


class AnotherScreen(Screen):
    dl = ObjectProperty()
    l = 0
    limit = 3 # Fix your limit here 3 is an example


class ScreenManagement(ScreenManager):
    m_s = ObjectProperty() # Here I will keep the value of the MainScreen
    a_s = ObjectProperty() # Here the AnotherScreen so I can use them later


class Stacks(StackLayout):
    pass


present = Builder.load_file('hellokivy2.kv')  # Specifying location of kv file


class MainApp(App):

    def build(self):
        return present

    def drinksSelect(self,value):  # creating a button by referring the id of the layout in which to create button
        print(value)
        if self.root.a_s.l < self.root.a_s.limit: # You know what I mean
            button = Button(text=str(value), size_hint= (0.2,0.4))
            self.root.a_s.ids['place_remaining'].add_widget(button)
            self.root.a_s.l += 1

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

kv：

#: import FadeTransition kivy.uix.screenmanager.FadeTransition

ScreenManagement:
    m_s: m_s # so I can use it in the .py file
    a_s:a_s # same here
    transition: FadeTransition()
    MainScreen:
        id: m_s
    AnotherScreen:
        id: a_s

<MainScreen>:
    name: "main"

    canvas.before:
        Color:
            rgba: 1, 1, 1, 1
        Rectangle:
            pos: self.pos
            size: self.size

    BoxLayout:

        orientation: 'vertical'
        size:root.size

        Button:
            text: "Slideshow"

        GridLayout:

            cols: 2

            Button:
                text: "Burger"


            Button:
                text: "Drinks"
                on_release: app.root.current = "other"

            Button:
                text: "Fries"

            Button:
                text: "Others"
        Label:
            text: "Your Cart"
            font_size: 40
            color:(0,0,0,1)
            size_hint_y: None
            canvas.before:
                Color:
                    rgba:150,10,200,0.5
                Rectangle:
                    pos: self.pos
                    size: self.size
<AnotherScreen>:
    name: "other"
    dl : drinksLayout
    canvas.before:
        Color:
            rgba: 1, 1, 1, 1
        Rectangle:
            pos: self.pos
            size: self.size

    BoxLayout:
        size:root.size
        orientation: 'vertical'
        GridLayout:
            size_hint_y:0.1
            orientation: 'vertical'
            rows: 1
            Button:
                color: 1,1,1,1
                font_size: 25
                size_hint_y:0.1
                text: "Back Home"
                on_release: app.root.current = "main"
            Label:
                text: "Project BAM"
                canvas.before:
                    Color:
                        rgba: 0,0,0,1
                    Rectangle:
                        pos: self.pos
                        size: self.size
            Button:
                color: 1,1,1,1
                font_size: 25
                size_hint_y:0.1
                text: "Profile"
                on_release: app.root.current = "main"
        Button:
            color: 1,1,1,1
            font_size: 25
            size_hint_y:0.9
            text: "Whats New"
            on_release: app.root.current = "main"

        GridLayout:
            rows: 2
            Button:
                text: "Pepsi"
                on_release: app.drinksSelect(1)

            Button:
                text: "7up"
                on_release: app.drinksSelect(2)
            Button:
                text: "Fanta"
                on_release: app.drinksSelect(3)
            Button:
                text: "Mountain Dew"
                on_release: app.drinksSelect(4)
            Button:
                text: "Diet Pepsi"
                on_release: app.drinksSelect(5)
            Button:
                text: "Sprite"
                on_release: app.drinksSelect(6)

        GridLayout:
            id: drinksLayout
            size_hint_y: 0.3
            orientation: 'horizontal'
            rows: 1
            GridLayout:
                id: place_remaining
                rows: 1
                size_hint_x: 80
            Button:
                id: label1
                width: 40 # Set the size_hint_x to None and then set the width if you want a fixed dimension
                size_hint: None,0.4
                background_normal:'1.jpg'
                text: 'B1'
            Button:
                id: label2
                width: 40
                size_hint: None,0.4
                background_normal:'1.jpg'
                text: 'B1'
            Button:
                id: label3
                width: 40
                size_hint: None,0.4
                background_normal:'1.jpg'
                text: 'B1'

输出：

我希望代码现在有点清楚了