我有一个 Recycler View，onRun 会显示，但是单击按钮后它将是空的，我想设置一个默认的 recycler 视图

Question

I currently have a recycler view that works off Latitude and Longitude within Android studio. On load due to using an emulator i pass a default location, this loads areas around the location within a map. I also have a spinner which allows you to change area and display markers on a map on screen. However the problem is when the Location which in my case is the current location (set to default emulator location Google Pixel San Francisco?) is used, the recycler view shows as empty, i want to edit my recycler view within my Adapter class so that IF the view is empty set the text to "No places around you" if code needed please ask.

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {

        QuietPlace quietPlace = mQuietPlace.get(position);
        if (mQuietPlace.size() > 0){
            TextView textView = holder.titleTextView;
        textView.setText(quietPlace.getName());
        TextView textView2 = holder.noiseTextView;
        textView2.setText(quietPlace.getNoise());
        TextView textView3 = holder.distanceTextView;
        textView3.setText(String.valueOf(quietPlace.getDistance()));
        }
        else {
            TextView textViewEmpty = holder.titleTextView;
            textViewEmpty.setText("No Quiet Places near your location");
            TextView textViewEmpty2 = holder.noiseTextView;
            textViewEmpty2.setText(" ");
            TextView textViewEmpty3 = holder.distanceTextView;
            textViewEmpty3.setText(" ");
        }
    }

Edit:

package com.example.myapplication;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.List;

public class QuietPlaceAdapter extends RecyclerView.Adapter<QuietPlaceAdapter.ViewHolder> {

    private List<QuietPlace> mQuietPlace;

    public QuietPlaceAdapter(List<QuietPlace> quietPlaces)
    {
        mQuietPlace = quietPlaces;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        Context context = parent.getContext();
        LayoutInflater inflater = LayoutInflater.from(context);
        View quietPlaceView = inflater.inflate(R.layout.recycler_view, parent, false);
        ViewHolder viewHolder = new ViewHolder(quietPlaceView);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        QuietPlace quietPlace = mQuietPlace.get(position);

        TextView textView = holder.titleTextView;
        textView.setText(quietPlace.getName());
        TextView textView2 = holder.noiseTextView;
        textView2.setText(quietPlace.getNoise());
        TextView textView3 = holder.distanceTextView;
        textView3.setText(String.valueOf(quietPlace.getDistance()));
    }

    @Override
    public int getItemCount() {
        return mQuietPlace.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        public TextView titleTextView;
        public TextView noiseTextView;
        public TextView distanceTextView;
        public ViewHolder(View itemView) {
            super(itemView);

            titleTextView = (TextView) itemView.findViewById(R.id.quietPlaceTitle);
            noiseTextView = (TextView) itemView.findViewById(R.id.quietPlaceNoise);
            distanceTextView = (TextView) itemView.findViewById(R.id.quietPlaceDistance);
        }
    }

}

Answer 1

Don't pass the list in constructor if it is dynamic.

Add this function in your adapter

public void setPanelList(List<QuietPlace> quietPlaces){

    mQuietPlace = quietPlaces;
    notifyDataSetChanged();
}

In activity, setPanelList(quietPlaces) when your quietPlaces changed.

quietPlaceAdapter.setPanelList(quietPlaces)

Hope this helps.