It's possible to delete previous items in a recyclerview?

Issue

I need to display in my RecyclerView some CardViews with a mapView in the card. So I follow some tutorial and I made it in my RecyclerView:

public class ShowParkAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>
{
private List<Location> locations;
private Context context;

public ShowParkAdapter(List<Location> locations,Context context)
{
    this.locations = locations;
    this.context = context;
}

public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
{
    MapViewListItemView mapViewListItemView = new MapViewListItemView(context);
    mapViewListItemView.mapViewOnCreate(null);
    ParkAdapter parkHolder = new ParkAdapter(mapViewListItemView);
    return parkHolder;
}

@Override

public void onBindViewHolder(RecyclerView.ViewHolder holder, int position)
{
  ParkAdapter mHolder = (ParkAdapter)holder;

  StringBuilder type, createdAt, stateAt, segnalationAt;
  String locate;
  Location location = locations.get(position);
  mHolder.setmMapViewListItemViewPutMarkers(location.getLatitude(),location.getLongitude(),location.getType());
  mHolder.mapViewListItemViewOnResume();

  locate = location.getType();

  type = new StringBuilder(mHolder.tipologia.getText().toString().trim());
  type.append(" ").append(locate);
  mHolder.tipologia.setText(type.toString());

  createdAt = new StringBuilder(mHolder.data.getText().toString().trim());
  createdAt.append(" ").append(location.getCreatedAt());
  mHolder.data.setText(createdAt.toString());

  stateAt = new StringBuilder(mHolder.state.getText().toString().trim());
  stateAt.append(" ").append("verificato");
  mHolder.state.setText(stateAt.toString());

  segnalationAt = new StringBuilder(mHolder.segnalations.getText().toString().trim());
  segnalationAt.append(" ").append("0");
  mHolder.segnalations.setText(segnalationAt.toString());

    notifyDataSetChanged();

}


public int getItemCount()
{
    return locations.size();
}

private class ParkAdapter extends RecyclerView.ViewHolder
{
  private MapViewListItemView mMapViewListItemView;

    TextView tipologia, data,state,segnalations;


  public ParkAdapter(final MapViewListItemView mapViewListItemView)
  {
      super(mapViewListItemView);
      mMapViewListItemView = mapViewListItemView;

      tipologia = (TextView)mapViewListItemView.findViewById(R.id.type);
      data = (TextView)mapViewListItemView.findViewById(R.id.addedAt);
      state = (TextView)mapViewListItemView.findViewById(R.id.state);
      segnalations = (TextView)mapViewListItemView.findViewById(R.id.signal);

      state.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View v) {
              showErrorMessage(context,mapViewListItemView.getResources().getString(R.string.infoStato));
          }
      });

      segnalations.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View v) {
              showErrorMessage(context,mapViewListItemView.getResources().getString(R.string.infoSign));
          }
      });


  }

    private void showErrorMessage(Context mContext,String message)
    {
        new AlertDialog.Builder(mContext)
                .setMessage(message)
                .setCancelable(false)
                .setPositiveButton("Ok", new DialogInterface.OnClickListener()
                {
                    public void onClick(DialogInterface dialog, int which)
                    {

                    }
                }).create().show();

    }

  public void setmMapViewListItemViewPutMarkers(double latitude, double longitude,String type)
  {
   if(mMapViewListItemView != null)
       mMapViewListItemView.putMarkers(latitude,longitude,type);

  }

  public void mapViewListItemViewOnCreate(Bundle savedInstanceState) {
      if (mMapViewListItemView != null) {
          mMapViewListItemView.mapViewOnCreate(savedInstanceState);
          Log.d("map","oncreate");
      }
  }

  public void mapViewListItemViewOnResume() {
      if (mMapViewListItemView != null) {
          mMapViewListItemView.mapViewOnResume();
          Log.d("map","onresume");
      }
  }

  public void mapViewListItemViewOnPause() {
      if (mMapViewListItemView != null) {
          mMapViewListItemView.mapViewOnPause();
          Log.d("map","onpause");
      }
  }

  public void mapViewListItemViewOnDestroy() {
      if (mMapViewListItemView != null) {
          mMapViewListItemView.mapViewOnDestroy();
          Log.d("map","ondestroy");
      }
  }

  public void mapViewListItemViewOnLowMemory() {
      if (mMapViewListItemView != null) {
          mMapViewListItemView.mapViewOnLowMemory();
      }
  }

  public void mapViewListItemViewOnSaveInstanceState(Bundle outState) {
      if (mMapViewListItemView != null) {
          mMapViewListItemView.mapViewOnSaveInstanceState(outState);
      }
  }
 } 
} 

but, when I show the result, I get this error:

I try to use notifyDataSetChanged(); but I give the same errors. How could I solve this problem? Thanks

Solution

I think that the bug is here:

type = new StringBuilder(mHolder.tipologia.getText().toString().trim());
type.append(" ").append(locate); 
mHolder.tipologia.setText(type.toString());

RecyclerView will re-use the view. And here you take the previous text and adding something. So, when a View is recycled, you append new data to the old data.

You can change to something like:

type = new StringBuilder("Base text: ");
type.append(locate); 
mHolder.tipologia.setText(type.toString());

Or simply:

mHolder.tipologia.setText("Base text: " + type.toString());

And with intl:

mHolder.tipologia.setText(context.getString(R.string.my_base_text) + type.toString());

PS: the same for the others text

Answered By - Kevin Robatel