控件自由布局.py

#pylint:disable=W0613
# -*-coding:utf-8-*-
import kivy
from kivy.app import App
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.uix.textinput import TextInput#引入输入框

kivy.resources.resource_add_path('font/')
font = kivy.resources.resource_find('DroidSansFallback.ttf')

class RootWidget(FloatLayout):
    def __init__(self, **kwargs):
        super(RootWidget, self).__init__(**kwargs)

        self.button_init =Button(
        text='计算',
        font_name = font,
        size_hint=(None, None),
        size=(200, 144),
        pos_hint={'center_x': .2, 'center_y': .9}
        )   # 按钮控件

        self.label = Label(
        text='',
        font_name = font,
        size_hint=(None, None),
        size=(200, 144),
        pos_hint={'center_x': .5, 'center_y': .9}
        )  # 标签控件，用于显示按钮状态

        self.textinput = TextInput(
        text='',
        font_name = font,
        size_hint=(None, None),
        size=(200, 144),
        pos_hint={'center_x': .3, 'center_y': .6}
        )  # 文本框控件，用于输入字符状态

        self.add_widget(self.button_init)  # 添加控件至布局
        self.add_widget(self.label)
        self.add_widget(self.textinput)

        self.button_init.bind(state=self.state_changed)  # 绑定按钮状态改变事件

    def state_changed(self, sender, state):
        """处理按钮状态改变事件"""
        c=self.textinput.text
        str=c

        def is_number(s):
            try:
                float(s)
                return True
            except ValueError:
                pass
            try:
                import unicodedata
                unicodedata.numeric(s)
                return True
            except (TypeError, ValueError):
                pass
            return False

        if is_number(str):
            a=float(str)
            b="%.3f" % (a+2)
            self.label.text=b
        else:
            self.textinput.text=''
            self.label.text='输入数字错误'

class MainApp(App):
    def build(self):
        return RootWidget()

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