fragment - Lateinit var 属性未初始化

Question

我用文本视图创建了一个片段，但每次运行代码时，我都会收到一条错误消息，提示“tipAmount 属性未初始化”。我似乎无法弄清楚出了什么问题。这是代码：

class ShowTipFragment : Fragment() {

  private lateinit var tipAmount : TextView

  override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                          savedInstanceState: Bundle?): View? {
    // Inflate the layout for this fragment
    val view = inflater.inflate(R.layout.fragment_show_tip, container, false)

    tipAmount = view.findViewById(R.id.tip_amount)
    tipAmount.setText("")

    return view
 }

 fun updateTextView (tip : String) {
    val tipText = "You should definitely tip $tip"
    tipAmount.setText(tipText)
 }
}