Python|使用 .kv 文件在 Kivy 中弹出窗口小部件

Kivy 是Python中一个独立于平台的 GUI 工具。因为它可以在Android、IOS、linux和Windows等平台上运行。它基本上是用来开发Android应用程序的，但这并不意味着它不能在桌面应用程序上使用。

👉🏽 Kivy Tutorial – Learn Kivy with Examples.

弹出小部件：

要使用弹出窗口，您必须导入：

from kivy.uix.popup import Popup

Popup 小部件用于创建弹出窗口。默认情况下，弹出窗口将覆盖整个“父”窗口。在创建弹窗时，至少要设置一个 Popup.title 和 Popup.content。
请记住一件事，小部件的默认大小是 size_hint=(1, 1)。如果您不希望弹出窗口全屏显示，则必须提供值小于 1 的尺寸提示（例如 size_hint=(.8, .8)）或停用 size_hint 并使用固定尺寸属性。

注意：弹出窗口是一个特殊的小部件。不要尝试将其作为孩子添加到任何其他小部件。如果这样做，Popup 将像普通小部件一样被处理，并且不会隐藏在后台创建，例如：

Python3

BoxLayout:
   MyPopup:  # bad !

基本方法：

1) import kivy
2) import kivyApp
3) import Widget
4) import Floatlayout
5) import Label
6) import popup
7) Set minimum version(optional)
8) Create widget class
9) Create Layout class :
10) create App class
9) create .kv file (name same as the app class):
        1) create Widget
        2) create popup
        3) Give label to popup
        4) create button to close popup
10) return Layout/widget/Class(according to requirement)
11) define popup function(Which shows the popup on press the button)
12) Run an instance of the class

方法的实施：

popup.py 文件

Python3

# Kivy example for the Popup widget
  
# Program to Show how to create a switch
# import kivy module   
import kivy 
     
# base Class of your App inherits from the App class.   
# app:always refers to the instance of your application  
from kivy.app import App
   
# this restrict the kivy version i.e 
# below this kivy version you cannot 
# use the app or software 
kivy.require('1.9.0')
  
# Widgets are elements of a graphical user
# interface that form part of the User Experience.
from kivy.uix.widget import Widget
# The Label widget is for rendering text. 
from kivy.uix.label import Label
  
# module consist the floatlayout 
# to work with FloatLayout first 
# you have to import it 
from kivy.uix.floatlayout import FloatLayout
  
# Popup widget is used to create popups.
# By default, the popup will cover
# the whole “parent” window.
# When you are creating a popup,
# you must at least set a Popup.title and Popup.content.
from kivy.uix.popup import Popup
  
  
# Creating a widget class
# through this we add button
# the commands of the class is in .kv file
class Widgets(Widget):
    def btn(self):
        # calling of the show popup function
        show_popup()
  
# Popup class is defined
# The command of the class is in .kv file
class Popups(FloatLayout):
    pass
  
# create App class
class MyApp(App):
    def build(self):
        # return the widget
        return Widgets()
  
# define popup function in this we create the popup
def show_popup():
    show = Popups()
  
    popupWindow = Popup(title ="Popup Window", content = show,
                        size_hint =(None, None), size =(200, 200))
  
    # open popup window
    popupWindow.open()
  
    # Attach close button press with popup.dismiss action
    # content.bind(on_press = popup.dismiss)
   
  
# run the App 
if __name__ == "__main__":
    MyApp().run()

.kv 文件实现：

Python3

# .kv file of the popup code
  
# Adding Button widget
:
    Button:
        text: "Press me"
        on_release: root.btn()
  
# Adding Label, Button to popup
:
      
    Label:
        text: "You pressed the button"
        size_hint: 0.6, 0.2
        pos_hint: {"x":0.2, "top":1}
  
    Button:
        text: "Close the popup"
        # set size of the button
        size_hint: 1, 0.4
        # set position of the button  
        pos_hint: {"x":0, "y":0.1}

输出：

当按钮按下弹出出现时，单击窗口中的任何位置，除了弹出屏幕弹出将消失：