为什么我的RecyclerView每次迭代都显示相同的值？

Question

它显示了正确的对象数，但为它们提供了相同的值。

背景：我正在努力构建一个类似Slack的应用程序。我正在使用回收站视图来显示频道列表。

这是我的适配器

class ChannelsAdapter(val context: Context, val channels: ArrayList<Channel>) :
    RecyclerView.Adapter<ChannelsAdapter.Holder>() {

    inner class Holder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val singleChannel = itemView.findViewById<TextView>(R.id.single_channel)

        fun bindText(textVar: String, context: Context) {
            singleChannel.text = textVar
        }
    }

    override fun onBindViewHolder(holder: Holder, position: Int) {
        holder.bindText(channels[position].toString(), context)
    }

    override fun getItemCount(): Int {
        return channels.count()
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): Holder {

        val view = LayoutInflater.from(parent.context)
            .inflate(R.layout.channel_list_layout, parent, false)
        return Holder(view)

    }
}

这是“频道”类：

class Channel(val name: String, val Description: String, val id: String) {

    override fun toString(): String {
        return ("#$name")
    }

}

这是分配给RecyclerView的数据的变量，以及从服务器和数据中提取数据的函数

object MessageService {

    val channels = ArrayList<Channel>()

    fun getChannels(context: Context, complete: (Boolean) -> Unit) {

        val channelsRequest =
            object : JsonArrayRequest(Method.GET, URL_GET_CHANNELS, null, Response.Listener { response ->

                try {

                    for (x in 0 until (response.length())) {
                        val channel = response.getJSONObject(0)
                        val channelName = channel.getString("name")
                        val channelDescription = channel.getString("description")
                        val channelId = channel.getString("_id")

                        val newChannel = Channel(channelName, channelDescription, channelId)
                        this.channels.add(newChannel)

                    }
                    complete(true)

                } catch (e: JSONException) {
                    Log.d("JSON", "EXC:" + e.localizedMessage)
                    complete(false)
                }

            }, Response.ErrorListener {
                Log.d("ERROR", "Could not retrieve channels")
                complete(false)
            }) {

                override fun getBodyContentType(): String {
                    return "application/json; charset=utf-8"
                }

                override fun getHeaders(): MutableMap<String, String> {
                    val headers = HashMap<String, String>()

                    headers.put("Authorization", "Bearer ${AuthService.authToken}")
                    return headers
                }
            }

        Volley.newRequestQueue(context).add(channelsRequest)

    }

}

该val从服务器获取其数据作为JsonArray。

Answer 1

只需像这样改变你的onBindViewHolder

override fun onBindViewHolder(holder: Holder, position: Int) {
        holder.bindText(channels[position], context)
    }

你的bindText就像这样

inner class Holder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val singleChannel = itemView.findViewById<TextView>(R.id.single_channel)

        fun bindText(data: Channel, context: Context) {
            singleChannel.text = data.name
        }
    }

Answer 2

检查您正在初始化Chanel的位置并传入频道列表。确保在将Channel附加到列表中的循环内初始化每个通道。发生在我身边的一段时间，例如

   while(true) {
   Channel myChanel= new Channel()
   myChanel.name = "name"
   channels.add(myChanel)
   } 
// Pass list into adapter. Convert to kotlin :)

Answer 3

我的问题是在循环中从服务器中提取信息，这是一个愚蠢的错误。

for (x in 0 until (response.length())) {
                        val channel = response.getJSONObject(0)
                        val channelName = channel.getString("name")
                        val channelDescription = channel.getString("description")
                        val channelId = channel.getString("_id")

我一直拉着对象“0”而不是“x”