app.py

"""
My first application
"""
import toga
from toga.style import Pack
from toga.style.pack import COLUMN, ROW


class HelloWorld(toga.App):
    def startup(self):
        main_box = toga.Box(style=Pack(direction=COLUMN))

        name_label = toga.Label(
            'Your name: ',
            style=Pack(padding=(0, 5))
        )
        self.name_input = toga.TextInput(style=Pack(flex=1))

        name_box = toga.Box(style=Pack(direction=ROW, padding=5))
        name_box.add(name_label)
        name_box.add(self.name_input)

        self.output_label = toga.Label(
            'Output: ',
            style=Pack(padding=(0, 5), flex=1)
        )
        name_box.add(self.output_label)

        button = toga.Button(
            'Say Hello!',
            on_press=self.say_hello,
            style=Pack(padding=5)
        )

        main_box.add(name_box)
        main_box.add(button)

        self.main_window = toga.MainWindow(title=self.formal_name)
        self.main_window.content = main_box
        self.main_window.show()

    def say_hello(self, widget):
        self.output_label.text = "Output: Hello, {}".format(self.name_input.value)


def main():
    return HelloWorld()