問題描述
我對使用 kivy 庫很陌生.
i'm pretty new at using kivy library.
我有一個 app.py 文件和一個 app.kv 文件，我的問題是我無法在按下按鈕時調用函數.
I have an app.py file and an app.kv file , my problem is that I can't call a function on button press.
app.py:
import kivy
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
class Launch(BoxLayout):
def __init__(self, **kwargs):
super(Launch, self).__init__(**kwargs)
def say_hello(self):
print "hello"
class App(App):
def build(self):
return Launch()
if __name__ == '__main__':
App().run()
app.kv:
#:kivy 1.9.1
<Launch>:
BoxLayout:
Button:
size:(80,80)
size_hint:(None,None)
text:"Click me"
on_press: say_hello
推薦答案
Mode:.kv
很簡單，say_hello 屬于 Launch 類，所以要在 .kv 文件中使用它，你必須編寫 <代碼>root.say_hello.請注意，say_hello 是您要執行的函數，因此您不必忘記 () ---> root.say_hello().
Mode:.kv
It's very simple, say_hello belongs to the Launch class so in order to use it in your .kv file you have to write root.say_hello. Note that say_hello is a function that you want to execute so you don't have to forget the () ---> root.say_hello().
另外，如果 say_hello 在 App 類中，您應該使用 App.say_hello() 因為它屬于應用程序.(注意:即使你的 App 類是 class MyFantasicApp(App): 它總是 App.say_hello() 或 app.say_hello() 我不記得了，抱歉).
Also, if say_hello were in App class you should use App.say_hello() because it belongs to the app. (Note: even if your App class were class MyFantasicApp(App): it would always be App.say_hello() or app.say_hello() I don't remember, sorry).
#:kivy 1.9.1
<Launch>:
BoxLayout:
Button:
size:(80,80)
size_hint:(None,None)
text:"Click me"
on_press: root.say_hello()
模式:.py
你可以綁定函數.
from kivy.uix.button import Button # You would need futhermore this
class Launch(BoxLayout):
def __init__(self, **kwargs):
super(Launch, self).__init__(**kwargs)
mybutton = Button(
text = 'Click me',
size = (80,80),
size_hint = (None,None)
)
mybutton.bind(on_press = self.say_hello) # Note: here say_hello doesn't have brackets.
Launch.add_widget(mybutton)
def say_hello(self):
print "hello"
為什么要使用 bind?對不起，不知道.但是您在 kivy 指南中使用了它.
Why use bind? Sorry, no idea. But you it's used in the kivy guide.
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