如何在 Kivy 中更新 StringProperty 变量

Question

我在 Kivy 中更新屏幕时遇到问题。

我正在尝试在 Kivy 中制作一个登录屏幕，我想将用户的所有信息存储在不同的变量中，以便算法可以解析它们并给它们打分，然后分配他们是个好去处。

基本上就是：填写信息---->算法计算---->去x房间

我的问题是在计算之后，"go to room"屏幕没有更新，也就是说人名和房间都是初始值。

这里是简化代码：

Python:

class Manual_insert(Screen):

    name_x = StringProperty()   
    room = ""

    def update_info(self):
        name_x =  self.ids.full_name.text
        print name_x



class First_room(Screen):
        names = StringProperty(str(Manual_insert.name_x)+ ", your assigned room is: " + str(Manual_insert.room)) 

和 KIVY 文件：

<Manual_insert>:
     name: "manual"
    Label:
        TextInput:
            id: full_name
            text: "Full Name"
            pos: root.center_x - (self.size[0] * 0.5), root.top  * 0.75

    Button:
        text: "Calculate"
        on_release: app.root.current = "first"
        on_release: root.update_info()
        pos: root.center_x - (self.size[0] * 0.5) , root.top * 0.05
        background_color: [3,1,0.2,.9]

 <First_room>:
    name: 'first'
    Button:
         text: root.names
         on_release: app.root.current = "welcome"
         background_color: [1.78,3,2.91,0.8]
         font_size: 50

当我 运行 这个时，我在控制台上得到了名字，但在应用程序屏幕上我得到：

<StringProperty name=>, your assigned room is: 

谢谢你所做的一切，如果我不够清楚，请不要犹豫告诉我。

Answer 1

解决方案

详情请参考代码片段和示例。

kv 文件

1. 每个屏幕添加ids
2. 在按钮（计算）的 on_release 事件下，在切换到下一个屏幕之前调用 root.update_info() 方法。

片段

<ScreenManagement>:
    Manual_insert:
        id: manual_insert

    First_room:
        id: first_room

    Welcome:
        id: welcome

Python代码

1. 将 self 添加到 class 方法中的 StringProperty。
2. 添加 manager.ids.manual_insert 以访问 class Manual_insert()
中的字符串属性

片段

class Manual_insert(Screen):

    name_x = StringProperty('')
    room = StringProperty('')

    def update_info(self):
        self.name_x = self.ids.full_name.text
        print(self.name_x)


class First_room(Screen):
    names = StringProperty('')

    def on_pre_enter(self, *args):
        self.names = self.manager.ids.manual_insert.name_x + ", your assigned room is: " + self.manager.ids.manual_insert.room

Screen default property manager

Each screen has by default a property manager that gives you the instance of the ScreenManager used.

ScreenManager Events

Events:

on_pre_enter: ()

Event fired when the screen is about to be used: the entering animation is started.

例子

main.py

from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.properties import StringProperty


class ScreenManagement(ScreenManager):
    pass


class Manual_insert(Screen):

    name_x = StringProperty('')
    room = StringProperty('')

    def update_info(self):
        self.name_x = self.ids.full_name.text
        print(self.name_x)


class First_room(Screen):
    names = StringProperty('')

    def on_pre_enter(self, *args):
        self.names = self.manager.ids.manual_insert.name_x + ", your assigned room is: " + self.manager.ids.manual_insert.room


class Welcome(Screen):
    pass


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


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

test.kv

#:kivy 1.11.0

<ScreenManagement>:
    Manual_insert:
        id: manual_insert

    First_room:
        id: first_room

    Welcome:
        id: welcome

<Manual_insert>:
    name: "manual"
    BoxLayout:
        Label:
            text: "Full Name"
        TextInput:
            id: full_name
            pos: root.center_x - (self.size[0] * 0.5), root.top  * 0.75

        Button:
            text: "Calculate"
            pos: root.center_x - (self.size[0] * 0.5) , root.top * 0.05
            background_color: [3,1,0.2,.9]
            on_release:
                root.update_info()
                root.manager.current = "first"

<First_room>:
    name: 'first'
    Button:
        text: root.names
        on_release: root.manager.current = "welcome"
        background_color: [1.78,3,2.91,0.8]
        font_size: 50

<Welcome>:
    Label:
        text: 'Welcome!'

输出