Kivy tutorial how to load kV file design interface by string (tutorial includes source code)

Actual combat needs

We sometimes need to be in a py In the file, run the code together with the interface configuration file ？

Solution

We can use Builder.load_string solve .

What is? Builder.load_string

stay Builder Insert a string into and return kv The root widget of the string

load_string ( string , ** kwargs )

Parameters

• rulesonly: bool, defaults to False
  If True, If you have a root widget in the definition , be Builder Exception will be thrown .

• filename: str, defaults to None
  If specified , Is used for indexing kv File name of the rule .

filename Parameters can be used to uninstall kv Unload the file in the same way kv character string . This can be achieved using pseudo file names , for example ：

Build.load_string("""
    <MyRule>:
        Label:
            text="Hello"
""", filename="myrule.kv")

You can uninstall ：

Build.unload_file("myrule.kv")

Combat code

from kivy.app import App
from kivy.lang import Builder

# File: clock.kv
KV = '''
BoxLayout:
    orientation: 'vertical'

    Label:
        text: '00:00:00'
'''


class ClockApp(App):
	def build(self):
		return Builder.load_string(KV)
	
if __name__ == '__main__':
    ClockApp().run()