Kivy库中的Spinner小部件|极客笔记

Kivy库中的Spinner小部件

Kivy是Python中的图形用户界面工具，它是平台无关的。使用Kivy开发的应用程序可以在IOS、Windows、Linux和Android操作系统上使用。Kivy工具的基本用途是开发Android操作系统的应用程序，但也可以用于开发桌面应用程序。

Spinner小部件：

用户可以使用以下命令导入Kivy库的Spinner小部件：

from kivy.uix.spinner import Spinner

一个Spinner小部件用于从一组中选择一个值。在默认状态下，Spinner显示当前选定的值。当用户点击Spinner时，它会显示一个下拉菜单，显示用户可以选择的所有其他可用值。

与组合框类似，Spinner小部件也用于为用户提供多选选项，供用户选择其中一个菜单。用户还可以将回调附加到Spinner小部件，以接收有关从小部件菜单中选择的值的通知。

流程：

步骤1 我们将导入kivy。
步骤2 我们将导入kivyApp。
步骤3 我们将导入标签。
步骤4 我们将导入Spinner。
步骤5 我们将导入FLoatlayout。
步骤6 我们将设置最低版本（此步骤是可选的）。
步骤7 我们将创建一个App类：
- 首先，我们将创建Spinner。
- 然后，我们将标签附加到Spinner。
- 然后，我们将附加一个回调。
步骤8 我们将返回布局/小部件/类（根据要求）。
步骤9 我们将运行该类的实例。

示例1

from kivy.config import Config

# In this code:
# 0 means off 
# 1 means ON 
# Here, we can also use 0 or 1 && True or False
Config.set('graphics', 'resizable', True)

# Here, we are writing a program for Showing how to create a switch
# first, we will import the kivy module   
import kivy 

# the, base Class of our Application is inherited from the App class.   
# app will refers to the instance of our application  
from kivy.app import App as app1

# this will limit the kivy version that means 
# below this kivy version we cannot 
# use the application or software 
kivy.require('1.9.0')

# The Label widget is for rendering text. 
from kivy.uix.label import Label as lab

# Now, we will import the spinner widget
from kivy.uix.spinner import Spinner as spin

# This module consist the float layout 
# for working with FloatLayout 
# we have to import it first 
from kivy.uix.floatlayout import FloatLayout as fl


# Now, we will create an Application by deriving from the App class
class Spinner_example(app1):

    # now we will define build 
    def build_1(self):

        # here, we will create floatlayout
        layout = fl()

        # then, we will create the spinner
        # first, we will configure spinner object and then add it to the layout
        self.spinnerObject = spin(text = "Option 1",
             values = ("Option 1", "Option 2", "Option 3", "Option 4", "Option 5", "Option 6"),
             background_color =(0.784, 0.443, 0.216, 1)) 

        self.spinnerObject.size_hint = (0.3, 0.2)

        self.spinnerObject.pos_hint ={'x': .35, 'y':.75}

        layout.add_widget(self.spinnerObject)

        # return the layout
        return layout;


# for, Running the application
if __name__ == '__main__':
    Spinner_example().run()

输出：

图像 1：

Kivy库中的Spinner小部件

图片2：

Kivy库中的Spinner小部件

现在，我们必须显示菜单列表中当前选择的选项。我们可以将标签显示在旋转器小部件旁边。

示例2

from kivy.config import Config

# In this code:
# 0 means off 
# 1 means ON 
# Here, we can also use 0 or 1 && True or False
Config.set('graphics', 'resizable', True)

# Here, we are writing a program for Showing how to create a switch
# first, we will import the kivy module   
import kivy 

# the, base Class of our Application is inherited from the App class.   
# app will refers to the instance of our application  
from kivy.app import App as app1

# this will limit the kivy version that means 
# below this kivy version we cannot 
# use the application or software 
kivy.require('1.9.0')

# The Label widget is for rendering text. 
from kivy.uix.label import Label as lab

# Now, we will import the spinner widget
from kivy.uix.spinner import Spinner as spin

# This module consist the float layout 
# for working with FloatLayout 
# we have to import it first 
from kivy.uix.floatlayout import FloatLayout as fl


# Now, we will create an Application by deriving from the App class
class Spinner_example(app1):

    # now we will define build 
    def build_1(self):

        # here, we will create floatlayout
        layout = fl()

        # then, we will create the spinner
        # first, we will configure spinner object and then add it to the layout
        self.spinObject = spin(text = "Option 1",
             values = ("Option 1", "Option 2", "Option 3", "Option 4", "Option 5", "Option 6"),
             background_color =(0.784, 0.443, 0.216, 1)) 

        self.spinObject.size_hint = (0.3, 0.2)

        self.spinObject.pos_hint ={'x': .35, 'y':.75}

        layout.add_widget(self.spinObject)
        self.spinObject.bind(text = self.on_spinner_select)

        # It will change the label information as well
        # It will add a label displaying the selection from the spinner
        self.spinSelection = Label(text = "Selected value in spinner widegt is: %s" 
                                                     %self.spinObject.text)

        layout.add_widget(self.spinSelection)
        self.spinSelection.pos_hint ={'x': .1, 'y':.3}

        return layout;

    # call back for the selection in spinner object
    def on_spinner_select(self, spin, text):
        self.spinSelection.text = ("Selected value in spinner widget is: %s" %self.spinObject.text)

        print('The spinner widget', spin, 'have text', text)


# Run the app
if __name__ == '__main__':
    Spinner_example().run()

输出：

图片1：

Kivy库中的Spinner小部件