03_building_gui.py 文件源码

def build(self):
        root_widget = BoxLayout(orientation='vertical')

        output_label = Label(size_hint_y=1)  

        button_symbols = ('1', '2', '3', '+',
                          '4', '5', '6', '-',
                          '7', '8', '9', '.',
                          '0', '*', '/', '=')

        button_grid = GridLayout(cols=4, size_hint_y=2) 
        for symbol in button_symbols:
            button_grid.add_widget(Button(text=symbol))

        clear_button = Button(text='clear', size_hint_y=None,
                              height=100)

        root_widget.add_widget(output_label)
        root_widget.add_widget(button_grid)
        root_widget.add_widget(clear_button)

        return root_widget