ButterKnifeActivity.kt

class ButterKnifeAcivity : AppCompatActivity() {

    @BindView(R.id.textView)
    lateinit var textView: TextView

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        ButterKnife.bind(this)

        update()
    }

    private fun update() {
        textView.text = "Text"
        textView.setTextColor(Color.RED)
        textView.textSize = 14.0f
    }
}