在 Kivy 中添加更多内容时如何增加布局的大小？

Question

如何更改 BoxLayout 小部件的大小，以便在向其中添加越来越多的内容时垂直滚动？您可以运行下面的脚本，但继续添加更多文本并单击发送以查看行为。

如果可以的话，我也在尝试在发送文本后清除输入字段messageInput.text，因为某种原因 widget.clear_widgets() 什么都不做。

from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.uix.textinput import TextInput
from kivy.core.window import Window
import datetime as dt
from kivy.uix.scrollview import ScrollView
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout

Window.clearcolor = (252, 235, 233, 0)

class NotificationMsgs(BoxLayout):

    orientation = 'vertical'
    spacing = 10
    padding = [50, 10, 50, 10]

    def __init__(self, **kwargs):
        super(NotificationMsgs, self).__init__(**kwargs)

        selectMsgsList = ['default dummy text']
        selectCreatedList = ['2017-08-10 00:00:00']

        notifBox = BoxLayout(orientation='vertical')
        # notifBox.bind(minimum_height=notifBox.setter('height'))
        notifScrlv = ScrollView(size_hint=(1,1), do_scroll_x=False, do_scroll_y=True)
        notifScrlv.add_widget(notifBox)

        r = 0
        for _ in zip(selectMsgsList, selectCreatedList):
            myMessage = Label(text="[color=000000]" + selectMsgsList[r] + "[/color]", markup=True)
            dateCreated = Label(text="[color=000000]" + selectCreatedList[r] + "[/color]", markup=True)
            notifBox.add_widget(myMessage)
            notifBox.add_widget(dateCreated)
            r += 1

        self.add_widget(notifScrlv)

        messageInput = TextInput(hint_text='type message...', multiline=True, size_hint_y=None, height=120, padding=30)
        self.add_widget(messageInput)


        def send_notification(self):
            createdDatetimeText = dt.datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S")

            for _ in zip(selectMsgsList, selectCreatedList):
                myMessage = Label(text="[color=000000]" + messageInput.text + "[/color]", markup=True)
                dateCreated = Label(text="[color=000000]" + createdDatetimeText + "[/color]", markup=True)

                # messageInput.clear_widgets()
                notifBox.canvas.ask_update()
                notifScrlv.canvas.ask_update()

                notifBox.add_widget(myMessage)
                notifBox.add_widget(dateCreated)


        self.add_widget(Button(text='send', font_size=40, size_hint_y=None, height=120, on_press=send_notification, background_color=[0,0,1,1], border=[0,1,1,1]))


class NotificationDemoApp(App):
    def build(self):
        return NotificationMsgs()

    def on_pause(self):
        return True

# if __name__ == '__main__':
NotificationDemoApp().run()

Answer 1

我已经解决了你的两个问题。您可能想自行调整大小。

1. 您不能使用 BoxLayout，因为它总是采用其父窗口小部件的大小。我已将其替换为 GridLayout。有很多描述如何一起使用 GridLayout 和 ScrollView。如https://stackoverflow.com/a/19035264/6646710

2. 接下来清除文本可以通过将TextInput的text属性设置为“”来实现

这里是代码。我做了各种改动，看不懂的可以问cmets。

from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.uix.textinput import TextInput
from kivy.core.window import Window
import datetime as dt
from kivy.uix.scrollview import ScrollView
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.gridlayout import GridLayout


Window.clearcolor = (252, 235, 233, 0)

class NotificationMsgs(BoxLayout):


    orientation = 'vertical'
    spacing = 10
    padding = [50, 10, 50, 10]

    def __init__(self, **kwargs):
        super(NotificationMsgs, self).__init__(**kwargs)

        selectMsgsList = ['default dummy text']
        selectCreatedList = ['2017-08-10 00:00:00']

        notifBox = GridLayout(cols=1, size_hint_y=None)
        notifBox.bind(minimum_height = notifBox.setter('height'))

        notifScrlv = ScrollView()
        notifScrlv.add_widget(notifBox)

        r = 0
        for _ in zip(selectMsgsList, selectCreatedList):
            myMessage = Label(text="[color=000000]" + selectMsgsList[r] + "[/color]", markup=True)
            dateCreated = Label(text="[color=000000]" + selectCreatedList[r] + "[/color]", markup=True)
            notifBox.add_widget(myMessage)
            notifBox.add_widget(dateCreated)
            r += 1

        self.add_widget(notifScrlv)

        messageInput = TextInput(hint_text='type message...', multiline=True, size_hint_y=None, height=120, padding=30)
        self.add_widget(messageInput)


        def send_notification(self):
            createdDatetimeText = dt.datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S")

            for _ in zip(selectMsgsList, selectCreatedList):
                myMessage = Label(text="[color=000000]" + messageInput.text + "[/color]", markup=True, size_hint_y=None, size=self.texture_size)
                dateCreated = Label(text="[color=000000]" + createdDatetimeText + "[/color]", markup=True)

                # messageInput.clear_widgets()
                notifBox.canvas.ask_update()
                notifScrlv.canvas.ask_update()

                notifBox.add_widget(myMessage)
                notifBox.add_widget(dateCreated)

            messageInput.text = ""

        self.add_widget(Button(text='send', font_size=40, size_hint_y=None, height=120, on_press=send_notification, background_color=[0,0,1,1], border=[0,1,1,1]))


class NotificationDemoApp(App):
    def build(self):
        return NotificationMsgs()

    def on_pause(self):
        return True

# if __name__ == '__main__':
NotificationDemoApp().run()