Android notifyDataSetChanged не обновляет вид на существующие элементы?

Question

Новое для android и с трудом выясняя почему notifyDataSetChanged(); не обновляет элементы, которые были удалены из вида при их повторном вставке. Работайте отлично при удалении элементов, но не при восстановлении элементов назад для просмотра, которые представляют собой существующие элементы. Любая помощь приветствуется.

UsersAdapter.java

public class UsersAdapter extends RecyclerView.Adapter<UsersAdapter.UserViewHolder> { 
private ArrayList<User> mDataSet; 
private Context context; 

private SQLiteDatabase db; 

public UsersAdapter(ArrayList<User> mDataSet, Context context) { 
    this.context = context; 
    this.mDataSet = mDataSet; 

    createDatabase(); 

} 

public void createDatabase(){ 
    db=context.openOrCreateDatabase("xxx", Context.MODE_PRIVATE, null); 
    db.execSQL("CREATE TABLE IF NOT EXISTS faces(id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, name VARCHAR,url VARCHAR);"); 
} 


@Override 
public UserViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 
    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.activity_favorites2, parent, false); 
    UserViewHolder userViewHolder = new UserViewHolder(v); 
    return userViewHolder; 
} 

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


    holder.name_entry.setText(mDataSet.get(position).getName()); 
    holder.email_entry.setText(mDataSet.get(position).getEmail()); 
    holder.icon_entry.setText(""+mDataSet.get(position).getName().charAt(0)); 

    String name = mDataSet.get(position).getName(); 
    String url = mDataSet.get(position).getEmail(); 

    Glide.with(context) 
      .load(url) 
      .asBitmap() 
      .placeholder(R.drawable.ic_blank) 
      .error(R.drawable.ic_blank) 
      .into(holder.ivFavorites); 
} 

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

public class UserViewHolder extends RecyclerView.ViewHolder { 
    CardView cardView; 
    TextView name_entry, email_entry, icon_entry; 
    ImageView ivFavorites; 

    UserViewHolder(View itemView) { 
     super(itemView); 
     cardView = (CardView) itemView.findViewById(R.id.user_layout); 
     name_entry = (TextView) itemView.findViewById(R.id.name_entry); 
     email_entry = (TextView) itemView.findViewById(R.id.email_entry); 
     icon_entry = (TextView) itemView.findViewById(R.id.icon_entry); 
     ivFavorites = (ImageView) itemView.findViewById(R.id.ivFavorites); 

     Typeface fontFamily2 = Typeface.createFromAsset(context.getAssets(), "fonts/fontawesome-webfont.ttf"); 
     TextView fontFamilyText2 = (TextView) itemView.findViewById(R.id.fontAwesomeDirectLink); 
     fontFamilyText2.setTypeface(fontFamily2); 
     fontFamilyText2.setText("\uf0c1"); 
     fontFamilyText2.setTextColor(ContextCompat.getColor(context, R.color.bg_screen3)); 
     fontFamilyText2.setOnClickListener(new View.OnClickListener() { 
      public void onClick(View view) { 
       context = view.getContext(); 
       final User mDataSet2 = mDataSet.get(getAdapterPosition());; 
       String url = mDataSet2.getEmail(); 
       String name = mDataSet2.getName(); 
       ClipboardManager clipboard = (ClipboardManager) context.getSystemService(Context.CLIPBOARD_SERVICE); 
       ClipData clip = ClipData.newPlainText("xxx direct link", url); 
       clipboard.setPrimaryClip(clip); 
       Snackbar snackbar = Snackbar 
         .make(view, "Copied " + name + "!", Snackbar.LENGTH_LONG) 
         .setActionTextColor(context.getResources().getColor(R.color.bg_screen3)) 
         .setAction("ADD IMG TAGS", new View.OnClickListener() { 
          @Override 
          public void onClick(View view) { 
           context = view.getContext(); 
           final User mDataSet2 = mDataSet.get(getAdapterPosition());; 
           String url = mDataSet2.getEmail(); 
           String name = mDataSet2.getName(); 
           ClipboardManager clipboard = (ClipboardManager) context.getSystemService(Context.CLIPBOARD_SERVICE); 
           ClipData clip = ClipData.newPlainText("xxx direct link with image tags", "[img]" + url + "[/img]"); 
           clipboard.setPrimaryClip(clip); 
           Snackbar snackbar1 = Snackbar.make(view, "Added image tags!", Snackbar.LENGTH_SHORT); 
           snackbar1.show(); 
          } 
         }); 

       snackbar.show(); 
      } 
     }); 

     Typeface fontFamily3 = Typeface.createFromAsset(context.getAssets(), "fonts/fontawesome-webfont.ttf"); 
     TextView fontFamilyText3 = (TextView) itemView.findViewById(R.id.fontAwesomeImageTagLink); 
     fontFamilyText3.setTypeface(fontFamily3); 
     fontFamilyText3.setText("\uf00d"); 
     fontFamilyText3.setTextColor(ContextCompat.getColor(context, R.color.dot_dark_screen1)); 
     fontFamilyText3.setOnClickListener(new View.OnClickListener() { 
      public void onClick(View view) { 
       context = view.getContext(); 
       final User mDataSet3 = mDataSet.get(getAdapterPosition());; 
       String url = mDataSet3.getEmail(); 
       String name = mDataSet3.getName(); 
       String query = "DELETE FROM faces WHERE url = ('"+url+"');"; 
       db.execSQL(query); 
       mDataSet.remove(getAdapterPosition()); 
       notifyDataSetChanged(); 
       Snackbar snackbar = Snackbar 
         .make(view, name + " Removed!", Snackbar.LENGTH_LONG) 
         .setActionTextColor(context.getResources().getColor(R.color.dot_dark_screen1)) 
         .setAction("UNDO", new View.OnClickListener() { 
          @Override 
          public void onClick(View view) { 
           context = view.getContext(); 
           final User mDataSet3 = mDataSet.get(getAdapterPosition());; 
           String url = mDataSet3.getEmail(); 
           String name = mDataSet3.getName(); 
           String query = "INSERT INTO faces (name,url) VALUES('"+name+"', '"+url+"');"; 
           db.execSQL(query); 
           Snackbar snackbar3 = Snackbar.make(view, name + " Favorited!", Snackbar.LENGTH_SHORT); 
           snackbar3.show(); 
          } 
         }); 
       snackbar.show(); 
      } 
     }); 


     Typeface fontFamily4 = Typeface.createFromAsset(context.getAssets(), "fonts/fontawesome-webfont.ttf"); 
     TextView fontFamilyText4 = (TextView) itemView.findViewById(R.id.fontAwesomeShare); 
     fontFamilyText4.setTypeface(fontFamily4); 
     fontFamilyText4.setText("\uf1e0"); 
     fontFamilyText4.setTextColor(ContextCompat.getColor(context, R.color.bg_screen3)); 
     fontFamilyText4.setOnClickListener(new View.OnClickListener() { 
      public void onClick(View view) { 
       context = view.getContext(); 
       final User mDataSet2 = mDataSet.get(getAdapterPosition());; 
       String url = mDataSet2.getEmail(); 
       String name = mDataSet2.getName(); 
       Drawable mDrawable = ivFavorites.getDrawable(); 
       Bitmap mBitmap = ((BitmapDrawable) mDrawable).getBitmap(); 
       Bitmap imageWithBG = Bitmap.createBitmap(600, 600, mBitmap.getConfig()); // Create another image the same size 
       imageWithBG.eraseColor(Color.WHITE); // set its background to white, or whatever color you want 
       Canvas canvas = new Canvas(imageWithBG); // create a canvas to draw on the new image 
       canvas.drawBitmap(mBitmap, 175, 100, null); // draw old image on the background 
       String path = MediaStore.Images.Media.insertImage(context.getContentResolver(), 
         imageWithBG, "xxx", null); 
       Uri uri = Uri.parse(path); 
       final Intent shareIntent = new Intent(Intent.ACTION_SEND); // THIS IS SLOW 
       shareIntent.putExtra(Intent.EXTRA_STREAM, uri); 
       shareIntent.setType("image/*"); 
       context.startActivity(shareIntent); 
      } 
     }); 

    } 
} 

@Override 
public void onAttachedToRecyclerView(RecyclerView recyclerView) { 
    super.onAttachedToRecyclerView(recyclerView); 
} 
} 

Answer 1

Заменить Ваш Snackbar код

Snackbar snackbar = Snackbar 
         .make(view, name + " Removed!", Snackbar.LENGTH_LONG) 
         .setActionTextColor(context.getResources().getColor(R.color.dot_dark_screen1)) 
         .setAction("UNDO", new View.OnClickListener() { 
          @Override 
          public void onClick(View view) { 
           context = view.getContext(); 
           final User mDataSet3 = mDataSet.get(getAdapterPosition());; 
           String url = mDataSet3.getEmail(); 
           String name = mDataSet3.getName(); 
           String query = "INSERT INTO faces (name,url) VALUES('"+name+"', '"+url+"');"; 
           db.execSQL(query); 
           mDataSet.add(mDataSet3); 
           notifyDataSetChanged(); 
           Snackbar snackbar3 = Snackbar.make(view, name + " Favorited!", Snackbar.LENGTH_SHORT); 
           snackbar3.show(); 
          } 
         }); 
       snackbar.show();