Python-Kivy 编码中的文本输入焦点

Question

python/kivy 编码的初学者。我正在尝试制作一个问题/答案类型的程序。

附加代码显示了我的问题的简化示例。它以remove_widget/add_widget 交替显示文本输入对话框和一键对话框。 我的问题是，起初，文本输入对话框在文本输入中具有焦点，但下一次出现时，它失去了焦点，尽管声明了self.gridlayout.txtinput.focus = True。知道如何保持专注吗？

我尝试添加延迟时间，也尝试在 AnswerChoiceScreen 的 on_enter 中添加 txtinput.focus 描述，但均无效。

main.py

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import NumericProperty
from kivy.uix.gridlayout import GridLayout
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.textinput import TextInput

sm = ScreenManager()
class QALayout1(BoxLayout):
    pass

class QALayout2(BoxLayout):
    pass

class AnswerChoiceScreen(Screen):

    def __init__(self, **kwargs):
        super(AnswerChoiceScreen, self).__init__(**kwargs)
        self.gridlayout = None
        self.gridlayout = QALayout2()
        self.add_widget(self.gridlayout)

    def _create_layout(self):
        if self.gridlayout is not None:
            self.remove_widget(self.gridlayout)
        self.add_widget(self.gridlayout)

    def button1_clicked(self, *args):
        if self.gridlayout is not None:
            self.remove_widget(self.gridlayout)
        self.gridlayout = QALayout2()
        self.add_widget(self.gridlayout)
        self.gridlayout.txtinput.focus = True

    def buttonOK_clicked(self, *args):
        if self.gridlayout is not None:
            self.remove_widget(self.gridlayout)
        self.gridlayout = QALayout1()
        self.add_widget(self.gridlayout)

class myApp(App):
    def build(self):  
        self.anschoi = AnswerChoiceScreen(name = 'anschoi') 
        sm.add_widget(self.anschoi)
        sm.current = 'anschoi'
        return sm

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

我的.kv

<AnswerChoiceScreen>:
    BoxLayout:
        orientation: 'vertical'
        padding: 10,40,10,40 
        spacing: 40 

<QALayout1>:
    Button1:
        id: btn1
        text: 'OK'
        on_press: root.parent.button1_clicked()  


<QALayout2>:
    txtinput: txtinput
    orientation: 'vertical'
    TextInput:
        id: txtinput
        text: ''
        multiline: False
        focus: True
    ButtonOK:
        id:ButtonOK
        text: 'OK'
        on_press: root.parent.buttonOK_clicked()  

<Button0@Button>:
<Button1@Button>:
<ButtonOK@Button>:

Answer 1

很奇怪，你需要做的就是改变

<QALayout1>:
    Button1:
        id: btn1
        text: 'OK'
        on_press: root.parent.button1_clicked()

到：

<QALayout1>:
    Button1:
        id: btn1
        text: 'OK'
        on_release: root.parent.button1_clicked()

将on_press 更改为on_release。我相信这与您的TextInput 的焦点设置在on_touch_down (on_press) 事件上有关，但随后由于on_touch_up (on_release) 事件而失去焦点。所以使用on_release 可以避免这个问题。通过运行原始代码并按下OK 按钮，您可以看到这种情况发生，但不要释放它。 TextInput 将保持焦点，直到您松开鼠标按钮。

你甚至不需要这条线：

self.gridlayout.txtinput.focus = True