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Kotlinで簡単なrecyclerViewを作成しようとしていますが、アダプターが適切に適用されていません

Volt経由で取得したデータを使用してKotlinで簡単なrecyclerViewを作成しようとしています（正しいデータが返されることを確認しています）、実際にアダプターを指定したときにエラー_E/RecyclerView: No adapter attached; skipping layout_作成したカスタムアダプタークラス：

_class ImageAdapter(var c: Context, var list: ArrayList<Image>) : RecyclerView.Adapter<ImageAdapter.ViewHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder? {
    val layoutInflater = LayoutInflater.from(parent.context)
    return ViewHolder(layoutInflater.inflate(R.layout.image_cardview, parent, false))
}

override fun onBindViewHolder(holder: ViewHolder, position: Int) {
    val imageUrl = list[position].url
    val submitter = list[position].submitter
    val color = list[position].color
    holder.submitterTV.text = submitter
    holder.card.setCardBackgroundColor(Color.parseColor(color))
}

override fun getItemCount() = list.size
class ViewHolder(itemView: View): RecyclerView.ViewHolder(itemView){
    val card = itemView.card
    val submitterTV = itemView.submitter
    val imageView = itemView.image
}

}
_

これは、MainActivtyクラスです。ここでは、JSONの実際の呼び出しを行い、作成したArrayListにアダプターをアタッチしようとします。

_class MainActivity : AppCompatActivity() {
val images = ArrayList<Image>()
override fun onCreate(savedInstanceState: Bundle?) {

    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    imageList.layoutManager = LinearLayoutManager(applicationContext)
    request("https://api.unsplash.com/photos/curated/?client_id=API_KEY")
    imageList.adapter = ImageAdapter(applicationContext, images)

}

private fun request(url: String) {
    val queue = Volley.newRequestQueue(this)
    val stringRequest = JsonArrayRequest(url, Response.Listener<JSONArray> { response ->
        try {
            for (i in 0..(response.length() - 1)) {
                val image: Image = Image(response.getJSONObject(i).getJSONObject("urls").getString("full"), response.getJSONObject(i).getJSONObject("user").getString("username"), response.getJSONObject(i).getString("color"))
                images.add(image)
            }

            imageList.adapter.notifyDataSetChanged()

        } catch (e: JSONException) {
            e.printStackTrace()
        }
    }, Response.ErrorListener { })
    queue.add(stringRequest)
}
}
_

3つのフィールドを格納するカスタムデータクラスImageを作成しました：imageUrl、submitter、color、これらはすべてJSONから派生しています。リクエストの完了後にアダプターでnotifyDataSetChanged()を呼び出すと、recyclerViewが更新されてアイテムが表示されますが、画面には何も表示されません。私がどこで混乱したかについて誰にもアイデアがありますか？

androidandroid-recyclerviewkotlin
11
rakeshdas

ソースコードはここからダウンロードできます（ Recyclerview In Kotlin Android ）

MainActivity.kt：

package com.deepshikha.recyclerviewkotlin
import Android.app.Activity
import Android.os.Bundle
import Android.support.v7.widget.LinearLayoutManager
import Android.view.Window
import Android.view.WindowManager
import Android.widget.LinearLayout
import kotlinx.Android.synthetic.main.activity_main.*
import net.simplifiedcoding.recyclerviewexample.CustomAdapter

class MainActivity : Activity() {


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        requestWindowFeature(Window.FEATURE_NO_TITLE)
        window.setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN)

        setContentView(R.layout.activity_main)

        val users = ArrayList<Model_Details>()
        users.add(Model_Details("Kaju katli", "Kaju katli, also known as kaju Katari or kaju barfi, is an Indian dessert similar to a barfi.",R.drawable.kaju))
        users.add(Model_Details("Doughnut", "The doughnut is popular in many countries and prepared in various forms as a sweet snack that can be homemade or purchased in bakeries, supermarkets, food stalls, and franchised specialty outlets",R.drawable.donuts))
        users.add(Model_Details("Panna cotta", "Panna cotta is an Italian dessert of sweetened cream thickened with gelatin and molded. The cream may be aromatized with rum, coffee, Vanilla, or other flavorings.",R.drawable.panna_cotta))
        users.add(Model_Details("Rose Cookies", "Rose cooky is a famous South Indian snack made during festivals",R.drawable.rosecookies))
        users.add(Model_Details("Belgian waffle", "In North America, Belgian waffles are a variety of waffle with a lighter batter, larger squares, and deeper pockets than ordinary American waffles",R.drawable.belgianwaffle))

        val obj_adapter = CustomAdapter(users)

        recyclerView.layoutManager = LinearLayoutManager(this, LinearLayout.VERTICAL, false)
        recyclerView.adapter = obj_adapter
    }


}

CustomAdapter.kt：

package net.simplifiedcoding.recyclerviewexample

import Android.support.v7.widget.RecyclerView
import Android.view.LayoutInflater
import Android.view.View
import Android.view.ViewGroup
import Android.widget.TextView
import com.deepshikha.recyclerviewkotlin.Model_Details
import com.deepshikha.recyclerviewkotlin.R
import kotlinx.Android.synthetic.main.adapter_details.view.*

class CustomAdapter(val userList: ArrayList<Model_Details>) : RecyclerView.Adapter<CustomAdapter.ViewHolder>() {

    //this method is returning the view for each item in the list
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CustomAdapter.ViewHolder {
        val v = LayoutInflater.from(parent.context).inflate(R.layout.adapter_details, parent, false)
        return ViewHolder(v)
    }

    //this method is binding the data on the list
    override fun onBindViewHolder(holder: CustomAdapter.ViewHolder, position: Int) {
        holder.bindItems(userList[position])
    }

    //this method is giving the size of the list
    override fun getItemCount(): Int {
        return userList.size
    }

    //the class is hodling the list view
    class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {

        fun bindItems(user: Model_Details) {
            itemView.tv_name.text=user.name
            itemView.tv_des.text=user.des
            itemView.iv_name.setImageResource(user.image)

        }
    }

}

ありがとう！

16
Deepshikha Puri

次の例を見てください。これでアイデアが得られると思います。

ここからサンプルを入手できます： https://github.com/Siddharha/RecyclerviewTest_Kotlin

主な活動

class MainActivity : AppCompatActivity() {
private var myAdapter: MyAdapter? = null
private var arrayList: ArrayList<MyItem>? = null
private var layoutManager: RecyclerView.LayoutManager? = null
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    initialize()
    setupList()
    loaddata()
}

private fun loaddata() {

    for (i in 0..9) {
        val myItem = MyItem()
        myItem.name = "Sid_" + i
        myItem.number = "098899876" + i
        arrayList!!.add(myItem)
    }

    myAdapter!!.notifyDataSetChanged()

}

private fun setupList() {
    rlItems!!.layoutManager = layoutManager
    rlItems!!.adapter = myAdapter
}

private fun initialize() {
    arrayList = ArrayList<MyItem>()
    layoutManager = LinearLayoutManager(this, LinearLayout.VERTICAL, false)
    myAdapter = MyAdapter(arrayList!!, this, R.layout.item_cell)

  }
}

アダプタクラス

internal class MyAdapter(private val arrayList: ArrayList<MyItem>,
                     private val context: Context,
                     private val layout: Int) : RecyclerView.Adapter<MyAdapter.ViewHolder>() {


override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyAdapter.ViewHolder {
    val v = LayoutInflater.from(parent.context).inflate(layout, parent, false)
    return ViewHolder(v)
}

override fun onBindViewHolder(holder: MyAdapter.ViewHolder, position: Int) {
    holder.bindItems(arrayList[position])
}

override fun getItemCount(): Int {
    return arrayList.size
}

internal inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {

    fun bindItems(items: MyItem) {
        itemView.tvName.text = items.name
        itemView.tvNumber.text = items.number
    }
  }
}

アイテムクラス

internal class MyItem {
var name: String? = null
var number: String? = null
}
4
Sid

参照リンクは以下のデリゲートアダプタを使用してみてください。

参照リンク： https://Android.jlelse.eu/keddit-part-4-recyclerview-delegate-adapters-data-classes-with-kotlin-9248f44327f7

1
Sanjay Bhalani

On .MainActivity.kt

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    //rcv is id of Recyclerview
    rcv.layoutManager = LinearLayoutManager(this)
    rcv.adapter = MyAdpater()
}

アダプタ作成用の新しい.ktファイルを作成

class MyAdpater : RecyclerView.Adapter<ViewHolder>() {
val arr = listOf("A", "B", "C", "D", "E") //static array
override fun onBindViewHolder(holder: ViewHolder, position: Int) {
    holder.textView.setText(arr.get(position)) //set text to textview by position
}

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
    return ViewHolder(TextView(parent.context))
 }

override fun getItemCount(): Int {
    return arr.count() //return array count
}}

class ViewHolder(val textView: TextView): RecyclerView.ViewHolder(textView){ //ViewHolder with textview}
0
iOS Lifee

コードを減らすのに役立つかもしれない素敵なアダプターを作成しました。

class ResultActivity : BaseActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.question_list_activity)

        if (intent != null) {
            var results = intent.getParcelableArrayListExtra<Parcelable>("keyResults") as ArrayList<ResultBO>

            if (results.size > 0) {
                recycler_view.adapter = ResultAdapter(results, object : OnRecyclerItemClickListener {
                    override fun onItemClicked(view: View?, position: Int) {
                        /*var intent = Intent(this@SubjectListActivity,McqActivity::class.Java)
                        intent.putExtra("keyTagBO",subjects.get(position))
                        startActivity(intent)*/
                    }
                });
            }
        }

    }
}

item_result.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:Android="http://schemas.Android.com/apk/res/Android"
    xmlns:app="http://schemas.Android.com/apk/res-auto"
    xmlns:tools="http://schemas.Android.com/tools"
    Android:layout_width="match_parent"
    Android:layout_height="wrap_content"
    Android:orientation="vertical">

    <TextView
        Android:id="@+id/titleTv"
        Android:layout_width="match_parent"
        Android:layout_height="wrap_content"
        Android:text="Dummy Value"
        Android:textAlignment="center"
        Android:textAppearance="@style/TextAppearance.AppCompat.Large" />

    <LinearLayout
        Android:layout_width="match_parent"
        Android:layout_height="wrap_content"
        Android:layout_marginTop="10dp"
        Android:orientation="horizontal">

        <TextView
            Android:id="@+id/option1Tv"
            Android:layout_width="0dp"
            Android:layout_height="wrap_content"
            Android:layout_weight="1"
            Android:text="Dummy"
            Android:textAlignment="center"
            Android:textAppearance="@style/TextAppearance.AppCompat.Medium" />

        <TextView
            Android:id="@+id/option2Tv"
            Android:layout_width="0dp"
            Android:layout_height="wrap_content"
            Android:layout_weight="1"
            Android:text="Dummy Value"
            Android:textAlignment="center"
            Android:textAppearance="@style/TextAppearance.AppCompat.Medium" />

    </LinearLayout>


    <LinearLayout
        Android:layout_width="match_parent"
        Android:layout_height="wrap_content"
        Android:layout_marginTop="10dp"
        Android:orientation="horizontal">

        <TextView
            Android:id="@+id/option3Tv"
            Android:layout_width="0dp"
            Android:layout_height="wrap_content"
            Android:layout_weight="1"
            Android:text="Dummy"
            Android:textAlignment="center"
            Android:textAppearance="@style/TextAppearance.AppCompat.Medium" />

        <TextView
            Android:id="@+id/option4Tv"
            Android:layout_width="0dp"
            Android:layout_height="wrap_content"
            Android:layout_weight="1"
            Android:text="Dummy Value"
            Android:textAlignment="center"
            Android:textAppearance="@style/TextAppearance.AppCompat.Medium" />

    </LinearLayout>


    <LinearLayout
        Android:layout_width="match_parent"
        Android:layout_height="wrap_content"
        Android:orientation="horizontal">


    </LinearLayout>
</LinearLayout>

ResultADapter.class

class ResultAdapter(items: List<ResultBO>, onRecyclerItemClickListener: OnRecyclerItemClickListener) : BaseAdapter<ResultBO, ResultViewHolder>(items, onRecyclerItemClickListener) {

    override fun onCreateViewHolder(parent: ViewGroup, pos: Int): ResultViewHolder {
        return ResultViewHolder(parent, R.layout.item_result,onRecyclerItemClickListener)
    }
}

BaseViewHolder.class

abstract class BaseViewHolder<T : BaseModel>(parent: ViewGroup, @LayoutRes itemLayoutId: Int,
                                             var onRecyclerItemClickListener: OnRecyclerItemClickListener) :
        RecyclerView.ViewHolder(LayoutInflater.from(parent.context).inflate(itemLayoutId, parent,
                false)), View.OnClickListener {

    override fun onClick(v: View?) {
        onRecyclerItemClickListener.onItemClicked(v, adapterPosition)
    }

    abstract fun bindData(data: T)

    init {
        itemView.setOnClickListener(this)
    }
}

BaseAdapter

abstract class BaseAdapter<T : BaseModel, U : BaseViewHolder<T>>
(var items: List<T>, var onRecyclerItemClickListener: OnRecyclerItemClickListener)
    : RecyclerView.Adapter<U>() {

    override fun getItemCount(): Int {
        return items.size
    }

    override fun onBindViewHolder(holder: U, pos: Int) {
        holder.bindData(items.get(pos))
    }
}

ResultViewHolder.class

class ResultViewHolder(parent: ViewGroup, itemLayoutId: Int, onRecyclerItemClickListener: OnRecyclerItemClickListener) : BaseViewHolder<ResultBO>(parent, itemLayoutId, onRecyclerItemClickListener) {

    override fun bindData(data: ResultBO) {
        itemView.titleTv.setText(data.questionBO.title)

        itemView.option1Tv.setText(data.questionBO.options.get(0))
        itemView.option2Tv.setText(data.questionBO.options.get(1))
        itemView.option3Tv.setText(data.questionBO.options.get(2))
        itemView.option4Tv.setText(data.questionBO.options.get(3))

        when(data.orignalAnswer()) {
            OptionType.A -> itemView.option1Tv.setBackgroundColor(Color.GREEN)
            OptionType.B -> itemView.option2Tv.setBackgroundColor(Color.GREEN)
            OptionType.C -> itemView.option3Tv.setBackgroundColor(Color.GREEN)
            OptionType.D -> itemView.option4Tv.setBackgroundColor(Color.GREEN)
        }

        if(!data.isCorrectlyAnswered()){
            when(data.selectedOption) {
                OptionType.A -> itemView.option1Tv.setBackgroundColor(Color.RED)
                OptionType.B -> itemView.option2Tv.setBackgroundColor(Color.RED)
                OptionType.C -> itemView.option3Tv.setBackgroundColor(Color.RED)
                OptionType.D -> itemView.option4Tv.setBackgroundColor(Color.RED)
            }
        }

    }
}
0
Xar E Ahmer

私のRecyclerViewアダプタは次のとおりです。

internal class OptionsAdapter : RecyclerView.Adapter<OptionsAdapter.ViewHolder>() {

private val mOptionList = ArrayList<Option>()
private var mOnItemClickListener: OnItemClickListener<Option>? = null

var data: List<Option>
    get() = mOptionList
    set(list) {
        mOptionList.clear()
        mOptionList.addAll(list)
        notifyDataSetChanged()
    }

fun setOnItemClickListener(listener: OnItemClickListener<Option>) {
    mOnItemClickListener = listener
}

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
    return ViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.layout_text, parent, false))
}

override fun onBindViewHolder(holder: ViewHolder, position: Int) {
    val option = getItem(position)
    holder.textViewOption.setText(option.text)
    holder.textViewDescription.setText(option.subText)
}



private fun getItem(index: Int): Option {
    return mOptionList[index]
}

override fun getItemCount(): Int {
    return mOptionList.size
}


internal inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
    var textViewOption: TextView
    var textViewDescription: TextView
    var imageViewOptionIcon: ImageView

    init {
        textViewOption = itemView.findViewById<TextView>(R.id.textview_option)
        imageViewOptionIcon = itemView.findViewById<ImageView>(R.id.imageview_option_icon)
        textViewDescription = itemView.findViewById<TextView>(R.id.textview_description)
        itemView.setOnClickListener {
            if (mOnItemClickListener != null) {
                mOnItemClickListener!!.onItemClick(getItem(adapterPosition))
            }
        }
    }
  }
}
0
Saurabh Padwekar