There was an application with ListView , I remake it under RecyclerView with CardView . Previously, lines from the list were deleted via the context menu. I tried to fasten the context menu to RecyclerView (for deletion) - it did not work ... Now I try to delete via LongClick . But if it turns out to delete the item, the list is not updated. For reading I use CursorLoader in a fragment.

Tell me how to organize the removal?

RecordAdapter

  public class RecordAdapter extends RecyclerView.Adapter<RecordAdapter.ViewHolder> { Cursor dataCursor; Context context; public static class ViewHolder extends RecyclerView.ViewHolder { public TextView date; public TextView distance; public ImageView imageView; public ViewHolder(View v) { super(v); date = (TextView) v.findViewById(R.id.tvDate); distance = (TextView) v.findViewById(R.id.tvTitle); imageView = (ImageView) v.findViewById(R.id.ivImg); } } public RecordAdapter(Activity mContext, Cursor cursor) { dataCursor = cursor; context = mContext; } @Override public RecordAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View cardview = LayoutInflater.from(parent.getContext()) .inflate(R.layout.item, parent, false); return new ViewHolder(cardview); } public Cursor swapCursor(Cursor cursor) { if (dataCursor == cursor) { return null; } Cursor oldCursor = dataCursor; this.dataCursor = cursor; if (cursor != null) { this.notifyDataSetChanged(); } return oldCursor; } @Override public void onBindViewHolder(ViewHolder holder, final int position) { dataCursor.moveToPosition(position); holder.itemView.setOnClickListener (new View.OnClickListener() { @Override public void onClick(View v) { if (dataCursor != null) { dataCursor.moveToPosition(position); Intent intent = new Intent(context, Note.class); long id = dataCursor.getLong(dataCursor.getColumnIndex(DB.COLUMN_ID)); intent.putExtra("id", id); context.startActivity(intent); } } }); holder.itemView.setOnLongClickListener(new View.OnLongClickListener() { @Override public boolean onLongClick(View v) { final AlertDialog.Builder builder = new AlertDialog.Builder(v.getContext()); builder.setTitle ("Удаление") .setMessage ("Удалить ? " ) .setNegativeButton("Отмена",new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { } }) .setPositiveButton("OK", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { // Тут хотел удалить элемент списка после чего нужно обновить список dataCursor.moveToPosition(position); long id = dataCursor.getLong(dataCursor.getColumnIndex(DB.COLUMN_ID)); DB notesDB = new DB(context); notesDB.open(); notesDB.delRec(DB.DB_TABLE_NOTES, id); notesDB.close(); notifyDataSetChanged(); } }); builder.create().show(); return true; } }); String date = dataCursor.getString(dataCursor.getColumnIndex(DB.COLUMN_DATE)); String title = dataCursor.getString(dataCursor.getColumnIndex(DB.COLUMN_TITLE)); String value = dataCursor.getString(dataCursor.getColumnIndex(DB.COLUMN_COLOR)); SimpleDateFormat sdf = new SimpleDateFormat("dd.MM.yyy"); Date resultdate = new Date(Long.parseLong(date)); String sdfDate = sdf.format(resultdate); if ( title.equals("")){ title = context.getResources().getString(R.string.non_title); } holder.date.setText(sdfDate); holder.distance.setText(title); GradientDrawable bgShape = (GradientDrawable) holder.imageView.getBackground(); bgShape.setColor( Integer.parseInt(value)); } @Override public long getItemId(int position) { return super.getItemId(position); } @Override public int getItemCount() { return (dataCursor == null) ? 0 : dataCursor.getCount(); } }

    1 answer 1

    After deletion write: notifyDataSetChanged();

    • Added onClick removal and notifyDataSetChanged (); but the list is not updated immediately. Maybe the deletion itself is not done correctly, or notifyDataSetChanged (); not put there? (corrected the code in the question, as amended) - Sergey Alexandrov
    • one
      @SergeyAlexandrov is most likely because the data is read from the dataCursor, and the data is deleted via notesDB. notifyDataSetChanged is called, but the data in the cursor has not changed. Most likely you need to call a level above swapCursor - hardsky
    • one
      Yes, most likely this was the problem. But I probably found a more correct method of deleting data than mine. Implementation via Callback. ru.stackoverflow.com/a/624618/245230 Now everything works as it should) - Sergey Alexandrov