kotlin记一次报错：java.lang.IllegalStateException: recycler_View must not be null

在Activity中创建一个RecyclerView可以正常创建以及显示，然后换了在 Fragment 中一直报错说不能为空。

然后上网查了一下：

结论得出，我们通常把initView方法写在onCreateView方法中，但是这个时候view可能并没有返回，所以就找不到了，所以我们可以把初始化操作放在onActivityCreated或onViewCreated中

只要把  RecyclerView放到  onViewCreated  中初始化即可：

override fun onViewCreated(view: View?, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        //模拟数据
        var user1 = UserData()
        user1.age = "23"
        user1.sex = "男"
        user1.userName = "张三"

        var user2 = UserData()
        user2.age = "30"
        user2.sex = "女"
        user2.userName = "李四"

        var user3 = UserData()
        user3.age = "25"
        user3.sex = "保密"
        user3.userName = "刘柳"

        arrayList.add(user1)
        arrayList.add(user2)
        arrayList.add(user3)


        val takePhotoAdapter = TakePhotoAdapter(arrayList)
        recycler_View.adapter = takePhotoAdapter

        val gridlayout = GridLayoutManager(context!!, 2)
        recycler_View.layoutManager=gridlayout
    }