Namaste.py

from kivy.app import App
from kivy.uix.gridlayout import GridLayout
from kivy.uix.label import Label
from kivy.uix.button import Button
from kivy.uix.textinput import TextInput
from kivy.core.window import Window

class Namaste(App):
    def build(self):
        self.window = GridLayout()
        self.window.cols = 1
        self.window.size_hint = (0.6, 0.7)
        self.window.pos_hint = {"center_x": 0.5, "center_y":0.5}



        # self.window.add_widget(Image(source="hello.jpg"))


        self.greeting = Label(
            text="what's your name?",
            font_size = 20,
            color='#ff6b81',
            )
        self.window.add_widget(self.greeting)

        self.user = TextInput(
            multiline=False,
            padding_y = (20,20),
            size_hint = (1, 0.5)
            )
        self.window.add_widget(self.user)

        self.button = Button(
            text = "Click me!",
            size_hint = (1, 0.5),
            bold = True,
            background_color = '#ff6b81')
        self.button.bind(on_press=self.callback)
        self.window.add_widget(self.button)

        return self.window

    def callback(self, instance):
        self.greeting.text = "Namaste "+ self.user.text + "!"

if __name__ == "__main__":
    Namaste().run()