Question

我试图从ABC.kv文件中的文本框中提取值。我在url发现了一个类似的问题。我尝试应用相同的解决方案，但错误不断出现。我不知道问题的根源在哪里。有人能够对我面临的问题有所了解。

ABC.py

    from kivy.app import App
from kivy.lang import Builder
from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import ObjectProperty
from kivy.uix.popup import Popup
from kivy.uix.screenmanager import ScreenManager, Screen, FadeTransition

class LoginScreen(BoxLayout):
    username_input = ObjectProperty()
    passwd_input = ObjectProperty()

    def __init__(self, **kwargs):
        super(LoginScreen, self).__init__(**kwargs)


        boxp = BoxLayout(orientation='vertical')
        labs = Label(text='')
        self.boxp = BoxLayout(orientation='vertical')
        self.labs = Label(text='')
        self.boxp.add_widget(self.labs)

        self.box = BoxLayout()
        self.box.orientation = 'horizontal'
        btn5 = Button(text="ok", size_hint=(0.5, 0.5))
        btn5.bind(on_release=self.checkin())
        self.box.add_widget(btn5)
        self.box.add_widget(Button(text='cancel', size_hint=(0.5, 0.5), on_release=self.cancel_button_hit))
        self.boxp.add_widget(self.box)
        self.popup = Popup(title="LOGIN SUCCESSFUL",
                            content=self.boxp,
                            size=(200, 200),
                            size_hint=(0.3, 0.3),
                            auto_dismiss=True)

    def checkin(self):
        if self.username_input.text=="root" and self.passwd_input.text=="root":
            self.labs.text = self.username_input.text
            self.popup.open()

        else:
            self.popup.title='Failed Login'
            self.labs.text = 'Failed'
            self.popup.open()
    def cancel_button_hit(self, instance):
        self.popup.dismiss()

class AnotherScreen(Screen):
    pass

class ScreenManagement(ScreenManager):
    pass

class MainApp(App):
    def build(self):
        return LoginScreen()

MainApp().run()

ABC.kv

#: import FadeTransition kivy.uix.screenmanager.FadeTransition
ScreenManagement:
    transition: FadeTransition()
    LoginScreen:
    AnotherScreen:

<LoginScreen>:
    orientation: "vertical"
    username_input: username
    passwd_input: passwd
    padding: 10
    spacing: 10
    name: 'login'
    BoxLayout:
        orientation: "vertical"
        Label:
            text: "Username"

        TextInput:
            id: username

        Label:
            text: "password"

        TextInput:
            id: passwd
            password: True

        Button:
            on_release: root.checkin()
            text: 'login'
            font_size: 50

<AnotherScreen>:
    name: 'other'

    Button:
        on_release: app.root.current = 'main'
        text: 'back to the home screen'
        font_size: 50

回溯：

Traceback (most recent call last):
   File "C:/Users/Admin/PycharmProjects/guihm/ABC.py", line 59, in <module>
     MainApp().run()
   File "C:\Python34\lib\site-packages\kivy\app.py", line 802, in run
     root = self.build()
   File "C:/Users/Admin/PycharmProjects/guihm/ABC.py", line 57, in build
     return LoginScreen()
   File "C:/Users/Admin/PycharmProjects/guihm/ABC.py", line 27, in __init__
     btn5.bind(on_release=self.checkin())
   File "C:/Users/Admin/PycharmProjects/guihm/ABC.py", line 38, in checkin
     if self.username_input.text=="root" and self.passwd_input.text=="root":
 AttributeError: 'NoneType' object has no attribute 'text'

Answer 1

username_input和password_input缺少自我。删除自我。在他们中

Answer 2

当用户点击btn5中的popup时，无法再次调用checkin方法。您已经在ABC.kv文件中的登录按钮定义中调用了它。首先，从checkin行btn5.bind(on_release=self.checkin())后删除括号。我建议调用另一种方法来处理on_release的{{1}}操作。

btn5

定义一个名为btn5.bind(on_release=self.success)

的方法

success

还将角色括号内的def success(self,instance): self.popup1.dismiss()类括在.kv文件中。

AttributeError：＆＃39; NoneType＆＃39;对象没有属性＆＃39; text＆＃39; kivy

2 个答案: