android - RecyclerView 不显示来自 firebase 的数据(Kotlin)

Question

谁能帮帮我？我尝试在线学习 android-firebase，但它是旧的。所以代码已经改变了。我被困在“onBindViewHolder”和“onCreateViewHolder”因为类(class)没有那个。

class UsersAdapter(databaseQuery: DatabaseReference, var context: Context):
    FirebaseRecyclerAdapter<Users, ViewHolder>(
        FirebaseRecyclerOptions.Builder<Users>().setQuery(databaseQuery, Users::class.java).build()
    ) {
    override fun onBindViewHolder(holder: ViewHolder, position: Int, model: Users) {

        var userID = getRef(position).key

        holder.bindView(model, context)

        holder.itemView.setOnClickListener {
            //todo create a popup dialog where user can do
            Toast.makeText(context, "user row click $userID", Toast.LENGTH_LONG).show()
        }


    }

    override fun onCreateViewHolder(p0: ViewGroup, p1: Int): ViewHolder {

        var view = LayoutInflater.from(p0.getContext())
            .inflate(R.layout.friendlist_row, p0, false)

        return ViewHolder(view,context)


    }

}

上面是我的 RecycleView 适配器

class ViewHolder(itemView: View, context: Context): RecyclerView.ViewHolder(itemView) {

  var userNameTxt: String ? = null
  var userStatusTxt: String ? = null
  var userProfilePicLink: String ? = null

  fun bindView(user: Users, context: Context) {
    var userName = itemView.findViewById < TextView > (R.id.friendlistNameTXID)
    var userStatus = itemView.findViewById < TextView > (R.id.friendlistStatusTXID)
    //        var userProfilePic = itemView.findViewById<CircleImageView>(R.id.friendlistImageIVID)

    //set the string so we can pass in the intent
    userNameTxt = user.usernickname
    userStatusTxt = user.userstatus
    //        userProfilePicLink = user.thumb_image

    userName.text = userNameTxt
    userStatus.text = userStatusTxt

    //        Picasso.get()
    //            .load(userProfilePicLink)
    //            .placeholder(R.drawable.ic_launcher_foreground)
    //            .into(userProfilePic)
  }
}

上面是我的 Adapter 的 ViewHolder

class UsersFragment: Fragment() {
  var mUserDatabase: DatabaseReference ? = null

  override fun onCreateView(
    inflater: LayoutInflater, container: ViewGroup ? ,
    savedInstanceState : Bundle ?
  ): View ? {
    // Inflate the layout for this fragment
    return inflater.inflate(R.layout.fragment_user, container, false)
  }


  override fun onViewCreated(view: View, savedInstanceState: Bundle ? ) {
    super.onViewCreated(view, savedInstanceState)

    var linearLayoutManager = LinearLayoutManager(context, LinearLayoutManager.VERTICAL, false)
    mUserDatabase = FirebaseDatabase.getInstance().reference.child("Users")

    friendlistRVID.setHasFixedSize(true)
    friendlistRVID.layoutManager = linearLayoutManager
    friendlistRVID.adapter = UsersAdapter(mUserDatabase!!, context!!)

  }

}

上面是我使用的 fragment ，里面有 RecycleView

它不会显示任何内容，也没有错误。提前谢谢你

Answer 1

您是否在适配器中使用了 itemCount？

override fun getItemCount(): Int {
        return count
    }