为什么在此视图示例中使用get（）？
private var _binding: ResultProfileBinding? = null
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
}
I want to know why "private val binding get() = _binding!!" was used here?
private var _binding: ResultProfileBinding? = null
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
}
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我假设您从文档中的此页面 。
他们的目标是为您提供一种访问
_binding值的方法，而无需处理_binding可以是null。在您未包含的示例的部分中，他们对binding有评论，指出它只能在oncreateview（）和ondestroyview之间使用。 （）。 如果您处于代码的一部分中，您可以在其中保证您的代码将在这两个回调之间执行，您可以参考binding，将返回_binding的值被胁迫到NOT-nulltype（result ProfileBinding而不是result ProfileBinding？）。但是，如果您弄错了，然后尝试在
oncreateview（）或之后 ondestroyview（）之前尝试引用binding代码> NullPoInterException 。就个人而言，我会避免这种方法。
I am assuming that you got that code from this page in the documentation.
Their objective is to give you a way to access the
_bindingvalue without needing to deal with the fact that_bindingcan benull. In the portion of their example that you did not include, they have a comment onbindingthat points out that it can only be used betweenonCreateView()andonDestroyView(). If you are in a part of your code where you can guarantee that your code will execute between those two callbacks, you can referencebinding, which will return the value of_bindingcoerced into a not-nulltype (ResultProfileBindinginstead ofResultProfileBinding?).However, if you get it wrong, and you try referencing
bindingbeforeonCreateView()or afteronDestroyView(), you will crash with aNullPointerException.Personally, I would avoid this approach.