如何从 kivy 中的 python 脚本访问 kv 中的属性

Question

以下是 main.py：

from kivy.app import App
from kivy.uix.behaviors import ButtonBehavior
from kivy.uix.image import Image
from kivy.uix.screenmanager import (ScreenManager, Screen)
from kivy.uix.button import Button
from kivy.properties import *
class EmotionsScreen(Screen):
    def button_press(self, emotion_str):
        print (self.ids[emotion_str].emotion)
class ScreenManagement(ScreenManager):
    pass
class HappyButton(ButtonBehavior, Image):
    def on_press(self):
        print(self.emotion)
class SadButton(ButtonBehavior, Image):
    def on_press(self):
        print(self.emotion)
class TiredButton(ButtonBehavior, Image):
    def on_press(self):
        print(self.emotion)
class MyApp(App):
    def build(self):
        sm = ScreenManagement()
        sm.current = 'Emotions'
        return sm
if __name__=='__main__':
    MyApp().run()

以下是myapp.kv文件的内容： : 情绪屏幕：

<EmotionsScreen>:
    name:'Emotions'
    HappyButton:
        id: happy
        source: "happy.png"
        pos: (-200, 100)
        emotion: "Happy"
    SadButton:
        id: sad
        source: "sad.png"
        pos: (0, 100)
        emotion: "Sad"
    TiredButton:
        id: tired
        source: "tired.png"
        pos: (200, 100)
        emotion: "Tired"

运行应用程序并单击三个按钮后，我得到以下行为：

• 单击快乐按钮会打印"悲伤":)
• 单击悲伤按钮打印"累了">
• 单击疲惫按钮可打印"疲倦">

即使我调用单个回调(在应用程序内部，提供参数(，也会发生上述情况，如下所示：

main.py：

from kivy.app import App
from kivy.uix.behaviors import ButtonBehavior
from kivy.uix.image import Image
from kivy.uix.screenmanager import (ScreenManager, Screen)
from kivy.uix.button import Button
from kivy.properties import *
class EmotionsScreen(Screen):
    pass
class ScreenManagement(ScreenManager):
    pass
class ImageButton(ButtonBehavior, Image):
    pass
class MyApp(App):
    def build(self):
        sm = ScreenManagement()
        sm.current = 'Emotions'
        return sm
    def button_press(self, *args):
        print (args)

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

myapp.kv：

<ScreenManagement>:
    EmotionsScreen:
<EmotionsScreen>:
    name:'Emotions'
    ImageButton:
        source: "happy.png"
        pos: (-200, 100)
        on_press: app.button_press("Happy")
    ImageButton:
        source: "sad.png"
        pos: (0, 100)
        on_press: app.button_press("Sad")
    ImageButton:
        source: "tired.png"
        pos: (200, 100)
        on_press: app.button_press("Tired")

我希望它分别在单击三个按钮后打印"快乐"，"悲伤"和"疲倦"。我可以知道我哪里出错了吗？

Answer 1

这些图像似乎是随机放置的。使用按钮作为模型的示例：

from kivy.app import App
from kivy.uix.image import Image
from kivy.uix.screenmanager import (ScreenManager, Screen)
from kivy.uix.button import Button
from kivy.properties import *
from kivy.lang import Builder
Builder.load_string('''
<EmotionsScreen>:
    name:'Emotions'
    HappyButton:
        id: happy
        pos: (-200, 100)
        text: "Happy"
        emotion: "Happy"
    SadButton:
        id: sad
        pos: (0, 100)
        text: "Sad"
        emotion: "Sad"
    TiredButton:
        id: tired
        pos: (200, 100)
        text: "Tired"
        emotion: "Tired"
''')
class EmotionsScreen(Screen):
    def button_press(self, emotion_str):
        print (self.ids[emotion_str].emotion)
class ScreenManagement(ScreenManager):
    pass
class HappyButton(Button):
    def on_press(self):
        print(self.emotion)
class SadButton(Button):
    def on_press(self):
        print(self.emotion)
class TiredButton(Button):
    def on_press(self):
        print(self.emotion)
class MyApp(App):
    def build(self):
        sm = ScreenManagement()
        sm.add_widget(EmotionsScreen())
        sm.current = 'Emotions'
        return sm
if __name__=='__main__':
    MyApp().run()

您应该在屏幕中放置一个布局来管理其小部件：

Builder.load_string('''
<EmotionsScreen>:
    name:'Emotions'
    BoxLayout:
        HappyButton:
            id: happy
            text: "Happy"
            emotion: "Happy"
        SadButton:
            id: sad
            text: "Sad"
            emotion: "Sad"
        TiredButton:
            id: tired
            text: "Tired"
            emotion: "Tired"
''')