Python Kivy - 无法将屏幕（ScreenManager）的TextInput值提交到另一个屏幕的列表视图

Question

我是 kivy 新手，需要有关 ListView 和 ScreenManager 的帮助。我设法在一个屏幕上使用 ListView，但我试图通过 ScreenManager 将它与两个屏幕一起使用： 我在 MainScreen 中有一个 ListView，并制作了一个导航到 ProfileScreen 的按钮，我将在 TextInput“abc”和“defe”中输入值并希望将它们提交到 ListView。 当我使用此代码运行 .py 文件时，它可以工作，但是当我在 ProfileScreen 上输入值并按“确定”时，它崩溃并说“ProfileScreen”没有属性“student_list”。如果我将 ProfileScreen(Screen) 的参数更改为 ProfileScreen(MainScreen) 它可以工作，但是 ProfileScreen 页面的内容是从 MainScreen 继承的，这是我不想要的。

我该如何解决这个问题？我将不胜感激任何形式的帮助，在此先感谢。

这是我的代码：

studentdb.py, 学生数据库.kv

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import ObjectProperty
from kivy.uix.listview import ListItemButton
from kivy.uix.screenmanager import ScreenManager, Screen

class StudentListButton(ListItemButton):
    pass

class Manager(ScreenManager):
    main_screen = ObjectProperty()
    profile_screen = ObjectProperty()

class MainScreen(Screen):
    first_name_text_input= ObjectProperty()
    last_name_text_input= ObjectProperty()
    student_list = ObjectProperty()

    def submit_student(self):
        # Get the student name from the TextInputs
        student_name = self.first_name_text_input.text + " " + self.last_name_text_input.text

        # Add the student to the ListView
        self.student_list.adapter.data.extend([student_name])

        # Reset the ListView
        self.student_list._trigger_reset_populate()

    def delete_student(self, *args):
        if self.student_list.adapter.selection:

            # Get the text from the item selected
            selection = self.student_list.adapter.selection[0].text

            # Remove the matching item
            self.student_list.adapter.data.remove(selection)

            # Reset the ListView
            self.student_list._trigger_reset_populate()

    def replace_student(self, *args):
        # If a list item is selected
        if self.student_list.adapter.selection:

            # Get the text from the item selected
            selection = self.student_list.adapter.selection[0].text

            # Remove the matching item
            self.student_list.adapter.data.remove(selection)

            # Get the student name from the TextInputs
            student_name = self.first_name_text_input.text + " " + self.last_name_text_input.text

            # Add the updated data to the list
            self.student_list.adapter.data.extend([student_name])

            # Reset the ListView
            self.student_list._trigger_reset_populate()

class ProfileScreen(Screen):
    abc_text_input=ObjectProperty()
    def_text_input=ObjectProperty()

    def okay(self):
        abc_name = self.abc_text_input.text + " " + self.def_text_input.text

        # Add the student to the ListView
        self.student_list.adapter.data.extend([abc_name])

        # Reset the ListView
        self.student_list._trigger_reset_populate()

class StudentDBApp(App):
    def build(self):
        return Manager()

if __name__=="__main__":
    StudentDBApp().run()
------------------------------------------------------------------
#: import main studentdb
#: import ListAdapter kivy.adapters.listadapter.ListAdapter
#: import ListItemButton kivy.uix.listview.ListItemButton

<MainScreen>:
    first_name_text_input: first_name
    last_name_text_input: last_name
    student_list: student_list
    BoxLayout:
        orientation: "vertical"
        BoxLayout:
            Label:
                text:"First Name:"
            TextInput:
                id: first_name
            Label:
                text:"Last Name:"
            TextInput:
                id: last_name
        BoxLayout:
            Button:
                text:"Submit"
                on_release: root.submit_student()
            Button:
                text:"Delete"
                on_release: root.delete_student()
            Button:
                text:"Replace"
                on_release: root.replace_student()
            Button:
                text: "New"
                on_release: root.manager.current="profile_screen"
        ListView:
            id: student_list
            adapter:
                ListAdapter(data=['Doug Smith'], cls=main.StudentListButton)

<ProfileScreen>:
    abc_text_input: abc
    def_text_input: defe
    BoxLayout:
        orientation: "vertical"
        BoxLayout:
            Button:
                text:"Back"
                on_release: root.manager.current="main_screen"
        BoxLayout:
            Label:
                text:"abc"
            TextInput:
                id: abc
            Label:
                text: "def"
            TextInput:
                id: defe
        BoxLayout:
            Button:
                text: "Okay"
                on_release: root.okay()

<Manager>:
    id: screen_manager
    main_screen: main_screen
    profile_screen: profile_screen

    MainScreen:
        id: main_screen
        name:"main_screen"
        manager: screen_manager

    ProfileScreen:
        id: profile_screen
        name: "profile_screen"
        manager: screen_manager

Answer 1

你的错误是student_list是MainScreen的属性而不是ProfileScreen所以你不能自己访问它，我建议阅读以下内容：What is the purpose of self?

在您的情况下，解决方案是通过ScreenManager 访问正确的屏幕：

def okay(self):
    abc_name = self.abc_text_input.text + " " + self.def_text_input.text
    main_screen = self.manager.get_screen('main_screen')

    # Add the student to the ListView
    main_screen.student_list.adapter.data.extend([abc_name])

    # Reset the ListView
    main_screen.student_list._trigger_reset_populate()

Answer 2

由于您已经在 ScreenManager 中将屏幕连接到 ObjectProperty，因此解决方案是

self.manager.main_screen...

注意

您可能想用 RecycleView 替换 ListView，因为 ListView 已被弃用。

List View

自 1.10.0 版起已弃用：ListView 已弃用，请使用 RecycleView 代替。

片段

def okay(self):
    abc_name = self.abc_text_input.text + " " + self.def_text_input.text

    # Add the student to the ListView
    self.manager.main_screen.student_list.adapter.data.extend([abc_name])

    # Reset the ListView
    self.manager.main_screen.student_list._trigger_reset_populate()

输出