Call notifyItemRangechanged when text in searchbar is written Recyclerview android

Question

I would like to add an animation on my RecyclerView every time the user types something in the SearchBar. I already have implemented a Filter method to filter the items, but fail to call notifyItemrangechanged in OnQuerytextChanged, so the appears. I have already tried something like this:

@Override
                public boolean onQueryTextChange(String newText) {


                    istyping = true;

                    ArrayList<String> templist = new ArrayList<>();

                    mSearchQuery = newText;

 //this line -->   adapter.notifyItemRangeChanged(0, namelistwithnumber.size());    <---



                    for (String temp : namelistwithnumber) {
                        if (temp.toLowerCase().contains(newText.toLowerCase())) {
                            templist.add(temp);
                        }
                    }

                    if (newText.isEmpty()){
                        mainlist.setAdapter(null);
                        adapter = new MyRecyclerViewAdapter(MainActivity.this, namelist);
                        mainlist.setAdapter(adapter);
                        adapter.notifyDataSetChanged();
                        istyping = false;
                    }

                    if (templist.size() == 0) {
                        mainlist.setAdapter(null);
                        noresults.setVisibility(View.VISIBLE);
                    } else {
                        if (!newText.isEmpty()){
                          adapter = new MyRecyclerViewAdapter(MainActivity.this, templist);
                            mainlist.setAdapter(adapter);
                            noresults.setVisibility(View.INVISIBLE);
                            adapter.setClickListener(MainActivity.this);

                        }
                        noresults.setVisibility(View.INVISIBLE);
                    }

                    return true;
                }

This is what I want to achieve:

Any help is appreciated!!

Answer 1

Sina's answer seems good, it has good practices(except redundant dataBinding), but since you did not accept it, i assume you don't want to rewrite your code with those additional concepts. So here is simple solution:

• Set setHasStableIds(true) to adapter
• Override getItemId(int position) inside adapter
• Add DefaultItemAnimator() to RecyclerView

---

Step by step guide:

1. Add default itemAnimator to your RecyclerView

mainlist.setItemAnimator(new DefaultItemAnimator());

2. Add function to adapter for updating list

You should not reinitialize your MyRecyclerViewAdapter every time you change List of items. Remove list from constructor! Instead declare member varialbe List<NameListwithNumber> nameListWithNumber = new ArrayList<>(); inside your dapter class and add a function to your adapter:

public void setItems(List<NameListwithNumber> newItems){
nameListWithNumber.clear();
nameListWithNumber.addAll(newItems);
notifydatasetChanged();
}

3. Initialize adapter and set setHasStableIds(true)

In your Activity declare your adapter as a global variable

private MyRecyclerViewAdapter  myAdapter;

(i'm not sure why would you need activity instance inside adapter tho)

and initialize it inside onCreate() method

 myAdapter = new MyRecyclerViewAdapter(MainActivity.this);
 myAdapter.setHasStableIds(true);
 mainList.setAdapter(myAdapter);

4. Override getItemId(int position) inside adapter

inside your adapter add this function:

@Override
public long getItemId(int position) {
   return nameListWithNumber.get(position).id;
}

if your model does not have unique id just use return nameListWithNumber.get(position).hashCode();

---

Finally Inside your public boolean onQueryTextChange(String newText) you need to change

  if (newText.isEmpty()) {
       adapter.setItems(nameList)
       istyping = false;
    }
  else {
    adapter.setItems(tempList)
    noresults.setVisibility(templist.size() == 0 ? View.VISIBLE : View.INVISIBLE)
}

---

Heres is the result of the exact same approach with just filtering done differently.