Question

我正在尝试在check_login()文件中调用方法kv，但无法识别，当我按下kv文件中的第一个按钮时，会产生此错误：< / p>

AttributeError: 'LoginWindow' object has no attribute 'check_login'

这是我的代码：

loginpageGUI.py

# importing library
import kivy

# version
kivy.require('1.11.1')

# importing functionality
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.floatlayout import FloatLayout
from kivy.properties import ObjectProperty
from kivy.core.window import Window
from kivy.uix.screenmanager import ScreenManager, Screen

# defining screens
class LoginWindow(Screen):
    pass
class PreferencesWindow(Screen):
    pass
class HomeWindow(Screen):
    pass
class WindowManager(ScreenManager):
    pass

# background
Window.clearcolor = (0.67, 0.83, 0.88, 1)

# creating layout class
class MyFloatLayout(FloatLayout):
    username = ObjectProperty(None)
    password = ObjectProperty(None)

    # defining processing method of the login button
    def check_login(self):

        """
        Processing, will fix later
        """

        print("Login succesful!")

        # reset the textinputs to empty strings once pressed and processed
        self.username.text = ''
        self.password.text = ''

        # navigate to home screen
        app.root.current = "home"
        root.manager.transition.direction = "right"

# linking .py with .kv
kv = Builder.load_file('gui.kv')

# creating application class that returns variable kv
class MyApp(App):
    def build(self):
        return (kv)

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

gui.kv

WindowManager:
    LoginWindow:
    HomeWindow:
    PreferencesWindow:

<Button>:
    font_size: 27
    size_hint: 0.2, 0.1
    background_color: 0.1, 0.5, 0.6, 1
    color: 1, 1, 1, 1
<Label>:
    font_size: 18
    size_hint: 0.1, 0.05
    color: 0.1, 0.5, 0.6, 1
<TextInput>:
    font_size: 14
    size_hint: 0.3, 0.05

<LoginWindow>:
    name: "login"

    MyFloatLayout:
        username: username
        password: password

        Button:
            pos_hint:{'center_y':0.43, 'center_x': 0.5}
            id: to_home
            text: "Login"
            on_press: root.check_login()
            color: 1, 1, 1, 1

        Label:
            pos_hint:{'center_y':0.57, 'center_x': 0.35}
            text: "Username"
        TextInput:
            pos_hint:{'center_y':0.57, 'center_x': 0.6}
            id: username
            multiline: False

        Label:
            pos_hint:{'center_y':0.5, 'center_x': 0.35}
            text: "Password"
        TextInput:
            pos_hint:{'center_y':0.5, 'center_x': 0.6}
            id: password
            multiline: False

<HomeWindow>:
    name: "home"

    MyFloatLayout:
        Button:
            text: "Log out"
            on_release:
                app.root.current = "login"
                root.manager.transition.direction = "right"
            pos_hint:{'center_x': 0.5, 'center_y': 0.57}

        Button:
            text: "Preferences"
            id: to_preferences
            on_release:
                app.root.current = "preferences"
                root.manager.transition.direction = "left"
            pos_hint:{'center_x': 0.5, 'center_y': 0.43}

<PreferencesWindow>
    name: "preferences"

    Button:
        text: "Home"
        id: to_home
        on_release:
            app.root.current = "home"
            root.manager.transition.direction = "right"
        pos_hint:{'center_x': 0.5, 'center_y': 0.43}

    Label:
        text: "To be further processed"

以某种方式，执行时无法识别类login_check()中的方法MyFloatLayout，这会使程序失败。我看过SO，但到目前为止还没有发现类似的问题。一些帮助会很棒。

编辑：我刚刚意识到，到目前为止，root是LoginWindow，因为这是我们在此讨论的按钮的根。我实际上想称该根的子代MyFloatLayout。我该怎么办？

Answer 1

您可以通过在kv文件中为undefined定义一个id并通过该id访问其功能来实现。更新后的gui.kv文件如下：

MyFloatLayout

但是loginpageGUI.py文件中也几乎没有问题。您需要在WindowManager: LoginWindow: HomeWindow: PreferencesWindow: <Button>: font_size: 27 size_hint: 0.2, 0.1 background_color: 0.1, 0.5, 0.6, 1 color: 1, 1, 1, 1 <Label>: font_size: 18 size_hint: 0.1, 0.05 color: 0.1, 0.5, 0.6, 1 <TextInput>: font_size: 14 size_hint: 0.3, 0.05 <LoginWindow>: name: "login" MyFloatLayout: id: myfloat username: username password: password Button: pos_hint:{'center_y':0.43, 'center_x': 0.5} id: to_home text: "Login" on_press: myfloat.check_login() color: 1, 1, 1, 1 Label: pos_hint:{'center_y':0.57, 'center_x': 0.35} text: "Username" TextInput: pos_hint:{'center_y':0.57, 'center_x': 0.6} id: username multiline: False Label: pos_hint:{'center_y':0.5, 'center_x': 0.35} text: "Password" TextInput: pos_hint:{'center_y':0.5, 'center_x': 0.6} id: password multiline: False <HomeWindow>: name: "home" MyFloatLayout: Button: text: "Log out" on_release: app.root.current = "login" root.manager.transition.direction = "right" pos_hint:{'center_x': 0.5, 'center_y': 0.57} Button: text: "Preferences" id: to_preferences on_release: app.root.current = "preferences" root.manager.transition.direction = "left" pos_hint:{'center_x': 0.5, 'center_y': 0.43} <PreferencesWindow> name: "preferences" Button: text: "Home" id: to_home on_release: app.root.current = "home" root.manager.transition.direction = "right" pos_hint:{'center_x': 0.5, 'center_y': 0.43} Label: text: "To be further processed"块中定义app，然后才能使用__name__。同样在app函数中，需要将check_login更改为root.manager.transition.direction。更新后的loginpageGUI.py如下：

app.root.transition.direction

从KV文件中的py文件调用方法/属性失败

1 个答案: