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

Question

我是 kivy 新手，需要 ListView 和 ScreenManager 方面的帮助。我设法在单个屏幕上使用 ListView，但我尝试通过 ScreenManager 在两个屏幕上使用它:我在主屏幕中有一个 ListView，并制作了一个按钮来导航到 ProfileScreen，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，它崩溃并显示“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，但是页面 ProfileScreen 的内容是从 MainScreen 继承的，这是我不想要的。

如何解决这个问题？我将不胜感激任何形式的帮助，提前致谢。

这是我的代码:

学生数据库.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

您的情况的错误是 student_list 是 MainScreen 的属性，而不是 ProfileScreen 因此您无法自行访问它，我建议阅读以下内容:What is the purpose of self?

就您而言，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()