android - 实时数据库中未显示回收站视图

Question

我有一个简单的回收器视图，它从数据库中读取列表，当我将它们记录到控制台时我可以看到数据，但它没有显示在回收器视图中

下面的函数在包含回收器视图的 xml 布局的 kotlin 片段类中

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


        view.recyclerView?.setHasFixedSize(true)
        view.recyclerView?.layoutManager = LinearLayoutManager(context)




        ref?.addChildEventListener(object : ChildEventListener {
            override fun onChildAdded(snapshot: DataSnapshot, previousChildName: String?) {
                val bal = snapshot.getValue<UserInfo.Uids>()

                if (bal != null) {
                 UserInfo.Uids(bal.email,bal.uid,bal.displayName)         
               }
                Log.d("RecyclerView",  UserInfo.Uids().toString())
                Log.d("RecyclerView", bal.toString())
                adapter = BalAdapter(requireContext(),  ArrayList<UserInfo.Uids>(),  R.layout.users)
                adapter!!.notifyDataSetChanged()
            }

            override fun onChildChanged(snapshot: DataSnapshot, previousChildName: String?) {
                TODO("Not yet implemented")
            }

                override fun onChildRemoved(snapshot: DataSnapshot) {
                TODO("Not yet implemented")
            }

            override fun onChildMoved(snapshot: DataSnapshot, previousChildName: String?) {
                TODO("Not yet implemented")
            }

            override fun onCancelled(p0: DatabaseError) {
                TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
            }




        })
        adapter = BalAdapter(requireContext(),  ArrayList<UserInfo.Uids>(),  R.layout.users)
        view.recyclerView.adapter = adapter
        adapter?.notifyDataSetChanged()

        return  view

    }

R.layout.fragment_chat_list是包含recycler view标签的xml

R.layout.users是数据xml

view.recyclerView是回收站视图标签

BalAdapter是适配器类，可以按要求提供，但我感觉那里的代码是正确的

UserInfo.Uids是数据类，包含name和email

adapter变量在之前声明override fun onCreateView

标签： androidkotlinfirebase-realtime-databaseandroid-recyclerviewdata-class