在 Kivy 中使用 jsonstore

Question

我创建了一个基于this question 的 GUI，同时尝试自学如何使用 jsonstore。我没有添加评论的声誉点，所以我在这里问我的问题。我想我已经有了基本的想法，但由于某种原因，我无法将数据保存到 json 文件中。我收到以下错误：

AttributeError: 'NoneType' object has no attribute 'text'

我已经尝试按照文档进行操作，但我看不到任何地方可以解释我做错了什么。

ma​​in.py

from kivy.storage.jsonstore import JsonStore
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen, ScreenManager
from kivy.core.window import Window
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.widget import Widget
from kivy.properties import BooleanProperty, ListProperty, StringProperty, ObjectProperty


Window.clearcolor = (0.02745098, 0.074509804, 0.121568627, 1)
Window.size = (2000, 900)

class TitleScreen(Screen):
    pass

class MainScreen(Screen):
    pass

class CreateProfile(Screen):
    First = ObjectProperty()
    Middle = ObjectProperty()
    Last = ObjectProperty()

    def __init__(self, **kwargs):
        super(CreateProfile, self).__init__(**kwargs)
        self.store = JsonStore("bco.json")
        self.load()

    def save(self):
        self.store.put('profile', first = self.label.text)
        self.store.put('profile', middle = self.label.text)
        self.store.put('profile', last = self.label.text)

    def load(self):
        try:
            self.Last.text = self.store.get('profile')['score']
        except KeyError:
            pass


class CreatePacket(Screen):
    pass

class ScreenManagement(ScreenManager):
    pass

presentation = Builder.load_file("customwidget.kv")

class CustomWidgetApp(App):
    def build(self):
        return presentation

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

customwidget.kv

#: import FadeTransition kivy.uix.screenmanager.FadeTransition
#: import hex kivy.utils.get_color_from_hex
#: import FocusBehaviors kivy.uix.behaviors.focus

ScreenManagement:
    transition: FadeTransition()
    TitleScreen:
    MainScreen:
    CreateProfile:
    CreatePacket:

<MainLabel@Label>:
    font_size:50
    bold: True
    size_hint_x: 1
    size_hint_y: 1.85
    color: 0.396078431, 0.803921569, 0.807843137, 1
    font_name: '/home/jarren/PycharmProjects/BCO_Form_Filler/practice/pirulen rg.ttf'

<SubLabel@Label>:
    font_size: 35
    bold: True
    halign: "center"
    size_hint_x: 1
    size_hint_y: 1.5
    color: 0.396078431, 0.803921569, 0.807843137, 1
    font_name: '/home/jarren/PycharmProjects/BCO_Form_Filler/practice/pirulen rg.ttf'

<OtherLabel@Label>:
    font_size: 12
    bold: True
    color: 0.396078431, 0.803921569, 0.807843137, 1
    font_name: '/home/jarren/PycharmProjects/BCO_Form_Filler/practice/pirulen rg.ttf'
    text_size: self.size

<Button@Button>:
    font_size: 20
    bold: True
    color: 0.396078431, 0.803921569, 0.807843137, 1
    font_name: '/home/jarren/PycharmProjects/BCO_Form_Filler/practice/pirulen rg.ttf'
    background_color: 0.02745098, 0.074509804, 0.121568627, .01
    canvas.before:
        Color:
            rgba: 0.396078431, 0.803921569, 0.807843137, 1
        Line:
            width: 2
            rectangle: self.x, self.y, self.width, self.height
    on_press: self.background_color = (0.396078431, 0.803921569, 0.807843137, 1)
    on_release: self.background_color = (0.02745098, 0.074509804, 0.121568627, .01)

# TODO: Create a focus behavior to "Tab" between widgets
<TextInput@TextInput>:
    font_size: 12
    color: 0.396078431, 0.803921569, 0.807843137, 1
    font_name: '/home/jarren/PycharmProjects/BCO_Form_Filler/practice/pirulen rg.ttf'
    padding_x: 10
    padding_y: 10
    focus_next: None
    focus_previous: None
    unfocus_on_touch: True
    background_color: 0.02745098, 0.074509804, 0.121568627, .01
    canvas.before:
        Color:
            rgba: 0.396078431, 0.803921569, 0.807843137, 1
        Line:
            width: 1
            rectangle: self.x, self.y, self.width, self.height

<TitleScreen>:
    id: "title"
    FloatLayout:
        MainLabel:
            text: "Easy Button"
            size_hint_x: 1
            size_hint_y: 1.25

        SubLabel:
            text: 'Test'
            size_hint_x: 1
            size_hint_y: 1
        Button:
            text: "Click Here To Continue"
            on_release: app.root.current = "main"
            size_hint: (.75, .15)
            pos_hint: {'x': .12, 'y': .2}

<MainScreen>:
    name: "main"
    MainLabel:
        text: "Home Page"
    BoxLayout:
        Button:
            on_release: app.root.current = "create_profile"
            text: "Create Profile"
            size_hint: (.5, .15)
        Button:
            on_release: app.root.current = "create_packet"
            text: "Create Packet"
            size_hint: (.5, .15)

<CreateProfile>:
    name: "create_profile"

    AnchorLayout:
        anchor_x: 'center'
        anchor_y: 'top'
        MainLabel:
            text: "Create Profile"
            size_hint: (1, .15)

    BoxLayout:
        size_hint: (.95, .2)
        pos_hint: {'x': 0, 'y': .85}
        spacing: 10
        padding: 10
        halign: "left"

        OtherLabel:
            text: "First"

        OtherLabel:
            text: "Middle"

        OtherLabel:
            text: "Last"

    BoxLayout:
        size_hint: (.95, .07)
        pos_hint: {'x': 0, 'y': .8}
        spacing: 20
        padding: 10
        halign: "right"
        text_size: self.size

        TextInput:
            id: 'First'


        TextInput:
            id: "Middle"


        TextInput:
            id: 'Last'    

    BoxLayout:

        Button:
            on_release: app.root.current = "main"
            text: "back Home"
            size_hint: (.5, .15)
        Button:
            on_release: root.save()
            text: "Save Profile"
            size_hint: (.5, .15)

<CreatePacket>:
    name: "create_packet"
    MainLabel:
        text: "Select Packet"
    FloatLayout:
        Button:
            on_release: app.root.current = "main"
            text: "back Home"
            size_hint: (1, .15)

Answer 1

我找到了一种解决方法，它仍然允许我使用 TinyDB 将信息附加到 JSON 中。这是更新的代码：

from kivy.app import App
from kivy.storage.jsonstore import JsonStore
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen, ScreenManager
from kivy.core.window import Window
from tinydb import TinyDB, Query
from kivy.uix.listview import ListItemButton


Window.clearcolor = (0.02745098, 0.074509804, 0.121568627, 1)
Window.size = (2000, 900)

db = TinyDB('bcodb.json')

class ProfileListButton(ListItemButton):
    pass

class TitleScreen(Screen):
    pass

class MainScreen(Screen):
    pass

class CreateProfile(Screen):
    def __init__(self, **kwargs):
        super(CreateProfile, self).__init__(**kwargs)
        self.store = JsonStore("bcodb.json")

    def save(self):
        db.insert({'first': self.first.text, 'middle': self.middle.text, 'last': self.last.text})

    def update(self):
        db.update({'first': self.first.text, 'middle': self.middle.text, 'last': self.last.text})

class CreatePacket(Screen):
    pass

class ScreenManagement(ScreenManager):
    pass


presentation = Builder.load_file("customwidget2.kv")

class CustomWidgetApp(App):
    def build(self):
        return presentation

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

使用我正在尝试开发的简单的类似数据库的程序很容易弄清楚。 .kv 文件也是一样的。

Answer 2

您的代码有几个问题，但主要问题是您不了解如何将任何 .kv 小部件公开给 .py，最简单的方法之一是尝试使用 ObjectProperty 但该属性未链接对于小部件，为了简单起见，我更喜欢在 .kv 中进行创建。

另一方面，我建议您避免滥用 try-except，因为它隐藏了错误，最好的办法是验证。

另一个错误是您正在覆盖 .json 中配置文件的值，想法是将所有内容保存在一个中。

综合以上，解决办法是：

*.py

from kivy.app import App
from kivy.storage.jsonstore import JsonStore
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen, ScreenManager
from kivy.core.window import Window
from kivy.clock import Clock


Window.clearcolor = (0.02745098, 0.074509804, 0.121568627, 1)
Window.size = (2000, 900)

class TitleScreen(Screen):
    pass

class MainScreen(Screen):
    pass

class CreateProfile(Screen):
    def __init__(self, **kwargs):
        super(CreateProfile, self).__init__(**kwargs)
        self.store = JsonStore("bco.json")
        Clock.schedule_once(lambda *args: self.load())

    def save(self):
        self.store.put('profile', 
            first = self.first.text,
            middle = self.middle.text,
            last = self.last.text)

    def load(self):
        if self.store.exists('profile'):
            profile = self.store.get('profile')
            v = [("first", self.first), ("middle", self.middle), ("last", self.last)]
            for key, ti in v:
                val = profile.get(key)
                if val:
                    ti.text = val

class CreatePacket(Screen):
    pass

class ScreenManagement(ScreenManager):
    pass

presentation = Builder.load_file("customwidget.kv")

class CustomWidgetApp(App):
    def build(self):
        return presentation

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

*.kv

#: import FadeTransition kivy.uix.screenmanager.FadeTransition
#: import hex kivy.utils.get_color_from_hex
#: import FocusBehaviors kivy.uix.behaviors.focus

ScreenManagement:
    transition: FadeTransition()
    TitleScreen:
    MainScreen:
    CreateProfile:
    CreatePacket:

<MainLabel@Label>:
    font_size:50
    bold: True
    size_hint_x: 1
    size_hint_y: 1.85
    color: 0.396078431, 0.803921569, 0.807843137, 1
    font_name: '/home/jarren/PycharmProjects/BCO_Form_Filler/practice/pirulen rg.ttf'

<SubLabel@Label>:
    font_size: 35
    bold: True
    halign: "center"
    size_hint_x: 1
    size_hint_y: 1.5
    color: 0.396078431, 0.803921569, 0.807843137, 1
    font_name: '/home/jarren/PycharmProjects/BCO_Form_Filler/practice/pirulen rg.ttf'

<OtherLabel@Label>:
    font_size: 12
    bold: True
    color: 0.396078431, 0.803921569, 0.807843137, 1
    font_name: '/home/jarren/PycharmProjects/BCO_Form_Filler/practice/pirulen rg.ttf'
    text_size: self.size

<Button@Button>:
    font_size: 20
    bold: True
    color: 0.396078431, 0.803921569, 0.807843137, 1
    font_name: '/home/jarren/PycharmProjects/BCO_Form_Filler/practice/pirulen rg.ttf'
    background_color: 0.02745098, 0.074509804, 0.121568627, .01
    canvas.before:
        Color:
            rgba: 0.396078431, 0.803921569, 0.807843137, 1
        Line:
            width: 2
            rectangle: self.x, self.y, self.width, self.height
    on_press: self.background_color = (0.396078431, 0.803921569, 0.807843137, 1)
    on_release: self.background_color = (0.02745098, 0.074509804, 0.121568627, .01)

# TODO: Create a focus behavior to "Tab" between widgets
<TextInput@TextInput>:
    font_size: 12
    color: 0.396078431, 0.803921569, 0.807843137, 1
    font_name: '/home/jarren/PycharmProjects/BCO_Form_Filler/practice/pirulen rg.ttf'
    padding_x: 10
    padding_y: 10
    focus_next: None
    focus_previous: None
    unfocus_on_touch: True
    background_color: 0.02745098, 0.074509804, 0.121568627, .01
    canvas.before:
        Color:
            rgba: 0.396078431, 0.803921569, 0.807843137, 1
        Line:
            width: 1
            rectangle: self.x, self.y, self.width, self.height

<TitleScreen>:
    id: "title"
    FloatLayout:
        MainLabel:
            text: "Easy Button"
            size_hint_x: 1
            size_hint_y: 1.25

        SubLabel:
            text: 'Test'
            size_hint_x: 1
            size_hint_y: 1
        Button:
            text: "Click Here To Continue"
            on_release: app.root.current = "main"
            size_hint: (.75, .15)
            pos_hint: {'x': .12, 'y': .2}

<MainScreen>:
    name: "main"
    MainLabel:
        text: "Home Page"
    BoxLayout:
        Button:
            on_release: app.root.current = "create_profile"
            text: "Create Profile"
            size_hint: (.5, .15)
        Button:
            on_release: app.root.current = "create_packet"
            text: "Create Packet"
            size_hint: (.5, .15)

<CreateProfile>:
    name: "create_profile"

    first: first
    middle: middle
    last: last

    AnchorLayout:
        anchor_x: 'center'
        anchor_y: 'top'
        MainLabel:
            text: "Create Profile"
            size_hint: (1, .15)

    BoxLayout:
        size_hint: (.95, .2)
        pos_hint: {'x': 0, 'y': .85}
        spacing: 10
        padding: 10
        halign: "left"

        OtherLabel:
            text: "First"

        OtherLabel:
            text: "Middle"

        OtherLabel:
            text: "Last"
    BoxLayout:
        size_hint: (.95, .07)
        pos_hint: {'x': 0, 'y': .8}
        spacing: 20
        padding: 10
        halign: "right"
        text_size: self.size
        TextInput:
            id: first
        TextInput:
            id: middle
        TextInput:
            id: last    

    BoxLayout:
        Button:
            on_release: app.root.current = "main"
            text: "back Home"
            size_hint: (.5, .15)
        Button:
            on_release: root.save()
            text: "Save Profile"
            size_hint: (.5, .15)

<CreatePacket>:
    name: "create_packet"
    MainLabel:
        text: "Select Packet"
    FloatLayout:
        Button:
            on_release: app.root.current = "main"
            text: "back Home"
            size_hint: (1, .15)