Recyclerview 项目不可见。 空屏来了

Question

I have a recyclerview in a activity. I am unable to show the list items.

In my activity, I am binding the adapter with the arrayList favCityList.

activity:

         recyclerView.apply {
        layoutManager = LinearLayoutManager(this@SearchFavrouiteActivity)

        city_list.adapter = com.example.diyatest.view.CityAdapter()
           (adapter as CityAdapter).updateItems(favCitesList);
       }

Here is my adapter. I am passing the list in UpdateItems ListView. While debugging I can see the compiler going there but It is not visible. Looks like some issue with the context.

       class CityAdapter() : RecyclerView.Adapter<CityAdapter.MyViewHolder>() {

      val mCityData = ArrayList<WeatherResponseData>()

fun updateItems(list: ArrayList<WeatherResponseData>){
    mCityData.clear()
    mCityData.addAll(list)
    notifyDataSetChanged()
}

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
    val view = LayoutInflater.from(parent.context).inflate(R.layout.content_search_favrouite, parent, false)
    return MyViewHolder(view)
}

override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
    mCityData[position].let {
        holder.bind(mCityData = it)
    }

}

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

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

    fun bind(mCityData: WeatherResponseData) {
        itemView.city_Country_txt.text = mCityData.name
        itemView.date_txt.text = (mCityData.date)?.toLong()?.let { getDate(it) }
        itemView.temp_txt.text=mCityData.main?.temp.toString()

    }

    private fun  getDate(date: Long): String {
        val timeFormatter = SimpleDateFormat("dd.MM.yyyy")
        return timeFormatter.format(Date(date*1000L))
    }


}

}

Here is my activity main_Xml. In this I am calling the recyclerview.

  <?xml version="1.0" encoding="utf-8"?>
   <androidx.coordinatorlayout.widget.CoordinatorLayout 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:background="@drawable/bg_gradient"
tools:context=".view.SearchFavrouiteActivity">
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">
<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Saved Cities"
    android:textSize="40dp"
    android:gravity="center"
    android:layout_gravity="center"
    android:textColor="@android:color/white"/>

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/city_list"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:scrollbars="vertical"
    android:layout_marginTop="30dp"
    android:background="@android:color/darker_gray"
    android:gravity="center_horizontal"
    />
</LinearLayout>

</androidx.coordinatorlayout.widget.CoordinatorLayout>

This is my adapter view. Here I am using cardview.

 <?xml version="1.0" encoding="utf-8"?>
 <androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@android:color/black"
android:layout_marginLeft="@dimen/main_padding"
android:layout_marginTop="@dimen/main_padding"
android:layout_marginRight="@dimen/main_padding">

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@android:color/white"
    android:padding="@dimen/main_padding">

    <TextView
        android:id="@+id/city_Country_txt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        tools:text="No City Data" />

    <TextView
        android:id="@+id/temp_txt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/city_Country_txt"
        android:layout_marginTop="10dp"
        tools:text="Degrees" />

    <TextView
        android:id="@+id/date_txt"
        android:layout_width="@dimen/list_weather_icon_size"
        android:layout_height="@dimen/list_weather_icon_size"
        android:layout_below="@+id/temp_txt"
        android:layout_alignParentRight="true"
        android:contentDescription="@string/weather_icon_description"
        android:text="date" />


</RelativeLayout>

</androidx.cardview.widget.CardView>

Answer 1

I have suggestion for you check and let me know if that work Change recyclerview code in xml

<androidx.recyclerview.widget.RecyclerView
android:id="@+id/city_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scrollbars="vertical"
android:layout_marginTop="30dp"
/>

Here this can be the issue

city_list.apply {
    layoutManager = LinearLayoutManager(this@SearchFavrouiteActivity,LinearLayoutManager.VERTICAL, false)
    val cityAdapter = CityAdapter()
    adapter = cityAdapter
    cityAdapter.updateItems(favCitesList);
   }