数据未显示在回收站视图中

Question

总的来说，我对移动开发和 kotlin 还很陌生。现在，我正在尝试使用数据库中的数据填充回收视图。问题是，我知道连接已建立，因为我可以在控制台上看到日志消息

我不太确定我现在做错了什么，我什至不明白问题出在哪里。我几乎尝试了在这里或其他网站上找到的所有解决方案，但没有任何效果。

适配器：

class restaurantadapter(private var restaurantList: ArrayList<Restaurant>, private val context: Context) : RecyclerView.Adapter<restaurantadapter.ViewHolder>() {

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

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

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
    val restaurant = restaurantList.get(position)
        holder.titleTextView?.text = restaurant.title
        holder.desTextView?.text = restaurant.description
        }
    class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
         var titleTextView: TextView? = null
         var desTextView: TextView? = null

        init {
            titleTextView = itemView.findViewById(R.id.restaurantname)
            desTextView = itemView.findViewById(R.id.restaurantdesc)

        }
    }

主要activity

class Main1Activity : AppCompatActivity() {

    var restaurantList: ArrayList<Restaurant> = ArrayList()
   private var adapter: restaurantadapter? = null


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main1)

        var recyclerView: RecyclerView = findViewById(R.id.restaurantslist)
        recyclerView.layoutManager= LinearLayoutManager(this@Main1Activity)
        adapter=restaurantadapter(restaurantList,this
        )

        recyclerView.adapter=adapter

      ApiClient.getApiClient()!!.create(ApiInterface::class.java)

        ApiClient.apiservice.getRestaurants()
            .enqueue(object: Callback<ArrayList<Restaurant>>{
                override fun onResponse(
                    call: Call<ArrayList<Restaurant>>,
                    response: Response<ArrayList<Restaurant>>
                )
                {
                   val response = response.body()
                    response?.let {
                        restaurantList.addAll(it)
                        adapter?.notifyDataSetChanged()

                    }
                }

                override fun onFailure(call: Call<ArrayList<Restaurant>>, t: Throwable) {
                    Toast.makeText(this@Main1Activity,"failure",Toast.LENGTH_SHORT).show()
                }
            })



    }

布局：

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView  xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    android:layout_margin="6dp"
    app:contentPadding="12dp"

    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    >

        <androidx.constraintlayout.widget.ConstraintLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="10dp">

        <TextView
            android:id="@+id/restaurantname"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginStart="20dp"
            android:layout_marginTop="16dp"
            android:layout_marginEnd="16dp"
            android:textColor="@color/black"
            android:textSize="22sp"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            android:layout_gravity="center"
          />

        <TextView
            android:id="@+id/restaurantdesc"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_marginStart="20dp"
            android:layout_marginTop="55dp"
            android:layout_marginEnd="16dp"
            android:textColor="@color/black"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/restaurantname"
            android:textSize="22sp"
             />
        </androidx.constraintlayout.widget.ConstraintLayout>

</androidx.cardview.widget.CardView>

Answer 1

您的问题是您将空列表 restaurantList 传递给适配器，然后将响应添加到此列表 restaurantList.addAll(it) 但这将更新您 activity 中的列表，而不是适配器中的列表，要解决此问题，您可以在适配器中创建方法来更新其列表

fun updateData(newRestaurant: ArrayList<Restaurant>) {
    restaurantList = newRestaurant
    notifyDataSetChanged()
}

onResponse 中的代码将是：

val response = response.body()
response?.let {
    adapter.updateData(it)
}

数据未显示在回收站视图中

Data not displaying in recycler View

java

android

kotlin

retrofit

retrofit2