This app is the example of how you should make your first Android app.
The app shows 3 basic components of an Android application, a TextView (text on the screen), an EditText (editable text) and a Button (button), organized vertically.
When you start the application, a default text is displayed in the TextView; When you fill in the EditText and press the button, the text placed in the TextView should be updated and only show the text previously written in the EditText.