kivy TextInput的StringProperty參考文本

Question

我想通過StringProperty獲取我的TextInput的文本，但它不起作用。我得到一個空字符串。在第二個示例中，我將整個TextInput聲明爲ObjectProperty，然後它可以工作。我的第一個例子有什麼問題？

如何使用StringProperty來定義TextInput中的文本？

第一個例子不打印的TextInput的文本 example1.py

from kivy.app import App 
from kivy.base import Builder 
from kivy.properties import StringProperty 
from kivy.uix.boxlayout import BoxLayout 

Builder.load_string(""" 
<rootwi>: 
    orientation: 'vertical' 
    Button: 
     on_press: root.print_txt() 
    TextInput: 
     text: root.textinputtext 
""") 
class rootwi(BoxLayout): 
    textinputtext = StringProperty() 

    def print_txt(self): 
     print(self.textinputtext) 


class MyApp(App): 
    def build(self): 
     return rootwi() 

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

第二個例子做的TextInput的打印文本，但使用OBJECTPROPERTY不StringProperty example2.py

from kivy.app import App 
from kivy.base import Builder 
from kivy.properties import ObjectProperty 
from kivy.uix.boxlayout import BoxLayout 
from kivy.clock import Clock 


Builder.load_string(""" 
<rootwi>: 
    txt: txt 
    orientation: 'vertical' 
    Button: 
     on_press: root.print_txt() 
    TextInput: 
     id: txt 
""") 
class rootwi(BoxLayout): 
    txt = ObjectProperty() 

    def print_txt(self): 
     print(self.txt.text) 


class MyApp(App): 
    def build(self): 
     return rootwi() 

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

如果我將文本設置爲特定的，它顯示在TextInput中。（但仍不能打印）

from kivy.app import App 
from kivy.base import Builder 
from kivy.properties import StringProperty 
from kivy.uix.boxlayout import BoxLayout 

Builder.load_string(""" 
<rootwi>: 
    orientation: 'vertical' 
    Button: 
     on_press: root.print_txt() 
    TextInput: 
     text: root.textinputtext 
""") 
class rootwi(BoxLayout): 
    textinputtext = StringProperty() 

    def __init__(self, **kwargs): 
     self.textinputtext = 'palim' 
     super(rootwi, self).__init__(**kwargs) 

    def print_txt(self): 
     print(self.textinputtext) 


class MyApp(App): 
    def build(self): 
     return rootwi() 

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

Answer 1

如果你想設置和使用StringProperty，那麼你應該創建一個雙向綁定獲取文本：

from kivy.app import App 
from kivy.base import Builder 
from kivy.properties import StringProperty, ObjectProperty 
from kivy.uix.boxlayout import BoxLayout 


Builder.load_string(""" 
<rootwi>: 
    orientation: 'vertical' 
    textinputtext: txt.text 
    Button: 
     on_press: root.print_txt() 
    TextInput: 
     id: txt 
     text: root.textinputtext 
""") 

class rootwi(BoxLayout): 
    textinputtext = StringProperty() 

    def __init__(self, **kwargs): 
     super(rootwi, self).__init__(**kwargs) 
     self.textinputtext = 'palim' 

    def print_txt(self): 
     print(self.textinputtext) 



class MyApp(App): 
    def build(self): 
     return rootwi() 

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

輸出：