android - 为什么在 Android 绑定(bind)示例中 Google 使用 val 绑定(bind)和 var _binding？

Question

示例是 the following :

private var _binding: ResultProfileBinding? = null
// This property is only valid between onCreateView and
// onDestroyView.
private val binding get() = _binding!!

override fun onCreateView(
    inflater: LayoutInflater,
    container: ViewGroup?,
    savedInstanceState: Bundle?
): View? {
    _binding = ResultProfileBinding.inflate(inflater, container, false)
    val view = binding.root
    return view
}

override fun onDestroyView() {
    super.onDestroyView()
    _binding = null
}

为什么使用 var _binding和 val binding ，它简单地得到 _binding ，而不是使用 lateinit var binding只要？这个选择背后有什么东西吗？
确实，在 activity's example ，他们实际上使用了 lateinit var :

private lateinit var binding: ResultProfileBinding

override fun onCreate(savedInstanceState: Bundle) {
    super.onCreate(savedInstanceState)
    binding = ResultProfileBinding.inflate(layoutInflater)
    val view = binding.root
    setContentView(view)
}

为什么无用地使代码复杂化？

Answer 1

这是命名约定，如果您有私有(private) Kotlin 属性，那么您应该以下划线开头。
Kotlin 文档:

Names for backing properties :If a class has two properties which are conceptually the same but one is part of a public API and another is an implementation detail, use an underscore as the prefix for the name of the private property:

class C {
    private val _elementList = mutableListOf<Element>()

    val elementList: List<Element>
         get() = _elementList
}