kivy访问子id

Question

我想访问孩子的id来决定是否删除小部件。我有以下代码：

在主.py在

#!/usr/bin/kivy
# -*- coding: utf-8 -*-

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout


class Terminator(BoxLayout):
    def DelButton(self):
        print("Deleting...")

        for child in self.children:
            print(child)
            print(child.text)

            if not child.id == 'deleto':
                print(child.id)
                #self.remove_widget(child)
            else:
                print('No delete')


class TestApp(App):
    def build(self):
        pass


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

在试验电压在

^{pr2}$

但是，当用：print(child.id)打印id时，它总是返回：None。即使print(child.text)正确返回Delete或{}不返回deleto，而是{}？在

我如何检查我不删除带有“delete”的按钮，而是删除所有其他按钮？在

Answer 1

正如您在documentation中看到的：

In a widget tree there is often a need to access/reference other widgets. The Kv Language provides a way to do this using id’s. Think of them as class level variables that can only be used in the Kv language.

描述了从Python代码访问id here。工作示例：

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.lang import Builder
from kivy.properties import ObjectProperty
from kivy.uix.button import Button

Builder.load_string("""
<Terminator>:
    id: masta
    orientation: 'vertical'

    MyButton:
        id: deleto

        button_id: deleto

        text: "Delete"
        on_release: masta.DelButton()

    MyButton
    MyButton
""")

class MyButton(Button):
    button_id = ObjectProperty(None)

class Terminator(BoxLayout):
    def DelButton(self):
        for child in self.children:
            print(child.button_id)       

class TestApp(App):
    def build(self):
        return Terminator()    

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

要跳过删除带有“Delete”标签的按钮，可以检查其text属性。从循环内部删除Hovewer将导致错误，因为在您迭代的列表更改后，某些子项将被跳过：

^{pr2}$

必须创建要删除的子项列表：

class Terminator(BoxLayout):
    def DelButton(self):
        for child in [child for child in self.children]:            
            self.remove_widget(child) # this will delete all children

在您的情况下：

class Terminator(BoxLayout):
    def DelButton(self):
        for child in [child for child in self.children if child.text != "Delete"]:            
            self.remove_widget(child)