Java – what is notifyItemRangeChanged(0, this.data.size()); In this example, how does it work?

I

understand how viewHolder’s onBindViewHolder works, but I don’t know how notifyItemRangeChanged(0, this.data.size()); How it works in this example and what it does.

The data provided to this adapter is in JSON format.

The adapters are as follows:

 public class AdapterQuestion extends RecyclerView.Adapter<AdapterQuestion.ViewQuestion>{

private LayoutInflater mLayoutInflater;

this is an arrayList of questionData objects
     private ArrayList<QuestionData> data =new ArrayList<>();

Created the layoutInflator
     public AdapterQuestion(Context context){
          get from context
          mLayoutInflater=LayoutInflater.from(context);
     }

public void setBloglist(ArrayList<QuestionData> data){
         this.data =data;
         notifyItemRangeChanged(0, this.data.size());
     }

@Override
     public ViewQuestion onCreateViewHolder(ViewGroup parent, int viewType) {
         inflates the customQuestion view or converts it to java code
         View view= mLayoutInflater.inflate(R.layout.customquestion, null);

We now want to convert the View into a ViewQuestion, view Question takes
        a view so we pass the view into view question and then return it.

ViewQuestion holder=new ViewQuestion(view);
        return holder;
    }

ViewGroup parent and ViewType are not being assigned.
    @Override
    public void onBindViewHolder(ViewQuestion holder, int position) {
         here we need to bind the data to our view, there is currently no Data!
         We need to get the data from our JSON
         Parameters is a ViewHolder and a Position
         This gives us the current information object from the whole arraylist
         data.get(position) data is the arraylist and we are getting the current position or index;
         That current obj is of Type QuestionData

QuestionData currentObj= data.get(position);

we are accessing the Inflated view, or saved view with holder
         holder.answerText is the textView in holder. We are then taking that current object
         We are getting the text of the current object and setting it to the AnswerText view
         holder.answerText.setText(currentObj.getMtext());
         holder.answerId.setText(currentObj.getId());
         holder.mVotes.setText(currentObj.getVotes());
         holder.mLikeButton.setTag(currentObj);
     }

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

public class ViewQuestion extends RecyclerView.ViewHolder{
        once we create it once the reclycer view will automatically recycle it
        private TextView answerText;
        private TextView answerId;
        private TextView mVotes;
        private LikeButton mLikeButton;

public ViewQuestion (View itemView){
            super(itemView);
            here we are finding the views by their ID
            answerText=(TextView)itemView.findViewById(R.id.answerText);
            answerId=(TextView)itemView.findViewById(R.id.answerId);
            mVotes=(TextView)itemView.findViewById(R.id.VoteTextView);
            mLikeButton=    (LikeButton)itemView.findViewById(R.id.heart_buttons);

mLikeButton.setOnLikeListener(new OnLikeListener() {

@Override
                public void liked(LikeButton likeButton) {
                    Voting vote = new Voting();
                    vote.onUpVote(convertToString(), 
                            getAdapterPosition(),ViewQuestion.this);
                    System.out.print("Adapter Position"+getAdapterPosition());
                }

@Override
                public void unLiked(LikeButton likeButton) {
                     Voting onDown=new Voting();
                     onDown.onDownVote(convertToString(), 
                             getAdapterPosition(), ViewQuestion.this);

}
            });
        }

public String getVoteView(){
            String voteView=mVotes.getText().toString();
            return voteView;
        }

public String convertToString(){
            String converted=answerId.getText().toString();
            return converted;
        }

public int convertToInt(){
            String converted=answerId.getText().toString();
            int ConvertedInt=Integer.parseInt(converted);
            return ConvertedInt;
        }
    }
}

When the data

to be set in the RecyclerView changes, the Adapter needs to be notified of the data change so that it can change the data > the Recycle Bin View.

Method

notifyItemRangedChanged(fromIndex,toIndex);

Used to notify the adapter that

some data set has changed throughout the data, it tells the adapter that the adapter should refresh the data and reload it into the recyclerView, starting with the fromIndex to toIndex of the incoming method.

Use this method if you have changed multiple but not all of the data, which is also in the cluster, so you can say that the data has changed from the 5th to the 10th index.

If all data changes the call:

notifyDataSetChanged();

If only one dataItem is changed, call:

notifyItemChanged(dataPosition);