問題描述

按下按鈕調(diào)用函數(shù)時，我無法將參數(shù)傳遞給函數(shù).用 kivy 語言可以這樣做:

I am having trouble passing parameters to function when calling it with button press. One could do it like this in kivy language:

Button: 
   on_press: root.my_function('btn1')

但我想用 python 來做，因為我想用循環(huán)創(chuàng)建更多的按鈕.目前我在 python 中這樣調(diào)用我的函數(shù):

but I would like to do it in python, as I would like to create a larger number of buttons with a loop. Currently I call my function in python like this:

Button(on_press=self.my_function)

但正如我所說，如果我嘗試像這樣將參數(shù)傳遞給函數(shù)，我會得到一個AssertionError: None is not callable"，如下所示:

but as I said, if I try to pass a parameter to the function like this, I get an 'AssertionError: None is not callable', like this:

Button(on_press=self.my_function('btn1'))

推薦答案

Button(on_press=self.my_function)

這是傳遞函數(shù)作為參數(shù).

Button(on_press=self.my_function('btn1'))

這是調(diào)用函數(shù)并將返回值作為參數(shù)傳遞給on_press.由于返回值為 None，因此您會收到錯誤消息.

This is calling the function and passing the returned value as the argument to on_press. Since the returned value is None, you get your error.

您需要傳遞一個調(diào)用普通函數(shù)并自動傳遞參數(shù)的新函數(shù).總的來說，使用 functools.partial 比較方便:

You instead need to pass a new function that calls your normal function and automatically passes the argument. In general, it's convenient to use functools.partial:

from functools import partial
Button(on_press=partial(self.my_function, 'btn1'))

您還可以使用 lambda 函數(shù):

You can also use a lambda function:

Button(on_press=lambda *args: self.my_function('btn1', *args))

這篇關于kivy python通過按鈕單擊將參數(shù)傳遞給函數(shù)的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網(wǎng)！