Android Programming: The Big Nerd Ranch Guide, 4th Edition

Typographical Conventions

All code and XML listings are in a fixed-width font. Code or XML that you need to type in is always bold. Code or XML that should be deleted is struck through. For example, in the following function implementation, you are deleting the call to Toast.makeText(…).show() and adding the call to checkAnswer(true).

trueButton.setOnClickListener { view: View ->
    Toast.makeText(
        this,
        R.string.correct_toast,
        Toast.LENGTH_SHORT
    )
        .show()
    checkAnswer(true)
}