kivy,如何通过文本更改触发事件 [英] kivy, how to trigger event by text change
问题描述
几个GUI工具箱包含诸如on_change
之类的事件,每次文本框中的文本更改时都会触发这些事件.
Several GUI toolboxes include events such as on_change
which are triggered every time the text in a textbox changes.
据此:
https://kivy.org/docs/api-kivy.uix.textinput. html on_text
事件应该相等.因此,我创建了一个TextInput框,期望每次更改一个字母时,该框的内容就会显示在终端中.这是代码:
According to this:
https://kivy.org/docs/api-kivy.uix.textinput.html the on_text
event should be equal. So, I created a single TextInput box expecting everytime a change a single letter, the content of the box to be displayed in the terminal. This is the code:
from kivy.app import App
from kivy.uix.textinput import TextInput
from kivy.uix.boxlayout import BoxLayout
class LoginScreen(BoxLayout):
def __init__(self, **kwargs):
super(LoginScreen, self).__init__(**kwargs)
self.orientation = 'horizontal'
self.mytext = TextInput(text='500', multiline = False)
self.add_widget(self.mytext)
self.mytext.bind(on_text = self.calc)
#self.mytext.bind(on_text_validate = self.calc)
def calc(self, mytext):
print mytext.text
class MyApp(App):
def build(self):
return LoginScreen()
if __name__ == '__main__':
MyApp().run()
但是,什么也没有发生,这显然意味着calc
函数根本没有被触发.请注意on_text_validate
事件可以正常工作,因为当我按Enter键时,该框的内容会在终端中打印出来.
Yet, nothing happens, which obviously means that the calc
function is not triggered at all. Mind that the on_text_validate
event works fine, because the contents of the box are printed in the terminal when I press Enter.
那么,我是否误解了on_text
事件?如果是,我该如何实现我的目标?
So, did I misunderstand the on_text
event, and if so, how can I accomplish my goal?
推荐答案
on_text
is not a TextInput
event. To run a callback when the text changes, you can bind text
property (where textinput’s text is stored):
from kivy.app import App
from kivy.uix.textinput import TextInput
from kivy.uix.boxlayout import BoxLayout
class LoginScreen(BoxLayout):
def __init__(self, **kwargs):
super(LoginScreen, self).__init__(**kwargs)
self.orientation = 'horizontal'
self.mytext = TextInput(text='500', multiline = False)
self.add_widget(self.mytext)
self.mytext.bind(text = self.calc)
def calc(self, instance, text):
print(text)
class MyApp(App):
def build(self):
return LoginScreen()
if __name__ == '__main__':
MyApp().run()
您可以使用 on_<property_name>
sintax:
You can create callback that automatic is called when a property change using on_<property_name>
sintax:
-
Kivy Languaje:
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.lang import Builder
Builder.load_string('''\
<LoginScreen>:
orientation: "horizontal"
TextInput:
text: "500"
on_text: root.calc(self.text)
''')
class LoginScreen(BoxLayout):
def __init__(self, **kwargs):
super(LoginScreen, self).__init__(**kwargs)
def calc(self, text):
print(text)
class MyApp(App):
def build(self):
return LoginScreen()
if __name__ == '__main__':
MyApp().run()
扩展小部件类:
from kivy.app import App
from kivy.uix.textinput import TextInput
from kivy.uix.boxlayout import BoxLayout
class My_TextInput(TextInput):
def __init__(self, **kwargs):
super(My_TextInput, self).__init__(**kwargs)
def on_text(self, instance, text):
print(text)
class LoginScreen(BoxLayout):
def __init__(self, **kwargs):
super(LoginScreen, self).__init__(**kwargs)
self.mytext = My_TextInput(text='500', multiline = False)
self.add_widget(self.mytext)
class MyApp(App):
def build(self):
return LoginScreen()
这篇关于kivy,如何通过文本更改触发事件的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!