RecyclerView: keep changing data during scroll

Question

I have a RecyclerView. Each row has a switch button, I click on the switch to change its state. when I scroll down and I come back, the recyclerview ignores the change I made in switch. all the recyclerview will reset.

I want to keep any change in the recyclerview during scroll.

here is my Adapter

public class LightAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>{


    private List<Light> mList;
    private LightItemClickListener mListener;
    private MainActivity mMainActivity;

    public LightAdapter(List<Light> mList, LightItemClickListener mListener, MainActivity mMainActivity) {
        this.mList = mList;
        this.mListener = mListener;
        this.mMainActivity = mMainActivity;

    }

    @Override
    public LightViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout_item, parent, false);
        return new LightViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
        Light light = mList.get(position);
        ((LightViewHolder)holder).getmSwitch().setChecked(light.isLightIsActivated());
        ((LightViewHolder)holder).getmSeekBar().setProgress(light.getLightingValue());
        if(light.isLightIsActivated())
        {
            ((LightViewHolder)holder).getmSwitchOnTextView().setVisibility(View.VISIBLE);
            ((LightViewHolder)holder).getmSwitchOffTextView().setVisibility(View.GONE);
        } else
        {
            ((LightViewHolder)holder).getmSwitchOnTextView().setVisibility(View.GONE);
            ((LightViewHolder)holder).getmSwitchOffTextView().setVisibility(View.VISIBLE);
        }

        ((LightViewHolder)holder).getmLightNameTextView().setText(light.getLightName());
        ((LightViewHolder)holder).populateItemView(light, mListener,mMainActivity);



    }


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

    public void add(List<Light> list) {
        mList.clear();
        mList.addAll(list);
        notifyDataSetChanged();
    }
}

and my ViewHolder

public class LightViewHolder extends RecyclerView.ViewHolder {

    private Context mContext;

    private SeekBar mSeekBar;

    private Switch mSwitch;
    private TextView mSwitchOffTextView;
    private TextView mSwitchOnTextView;

    private TextView mLightNameTextView;

    public LightViewHolder(View itemView) {
        super(itemView);
        mSeekBar = itemView.findViewById(R.id.seekBar1);
        mSwitch = itemView.findViewById(R.id.switch1);
        mSwitchOffTextView = itemView.findViewById(R.id.switch_off_textview);
        mSwitchOnTextView = itemView.findViewById(R.id.switch_on_textview);
        mLightNameTextView = itemView.findViewById(R.id.light_name_text_view);

    }

    public void populateItemView(final Light lightData, final LightItemClickListener onLightClickListener, MainActivity mMainActivity) {
        mContext =mMainActivity.getApplicationContext();

        switchClick(lightData,onLightClickListener);
        seekBarChangeValue(lightData,onLightClickListener);
    }
    public SeekBar getmSeekBar() {
        return mSeekBar;
    }
    public TextView getmSwitchOnTextView() {
        return mSwitchOnTextView;
    }

    public TextView getmSwitchOffTextView() {
        return mSwitchOffTextView;
    }

    public TextView getmLightNameTextView() {
        return mLightNameTextView;
    }
    public Switch getmSwitch() {
        return mSwitch;
    }

    public void switchClick(final Light light, final LightItemClickListener onLightClickListener) {
        mSwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if(mSwitch.isChecked())
                {

                    mSwitchOffTextView.setVisibility(View.GONE);
                    mSwitchOnTextView.setVisibility(View.VISIBLE);


                } else {
                    mSwitchOnTextView.setVisibility(View.GONE);
                    mSwitchOffTextView.setVisibility(View.VISIBLE);

                }

                onLightClickListener.onSwitchClickListener(light);
            }
        });

    }

    private void seekBarChangeValue(final Light light, final LightItemClickListener onLightClickListener) {


        mSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                Log.d("test","changed");
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
                Log.d("test","start");
            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {


                onLightClickListener.onSeekBarStopListener(light);
            }
        });

    }
}

Thanks in advance.

Answer 1

Nothing works as expected untill you make a List which rememebers the changed item.

I might post a example later. But think in that way were you can have data list that stores the click item to yes or no. Then Recyclerview will get the items from list and remember the position.

Answer 2

This is because on your checkedChange listener and seekbar listener, you are not mutating the state of Light object. For that, when your views are recycled, they are getting old data and thus you are having this weird behaviour You should write

light.setLightIsActivated(mSwitch.isChecked())

inside your checkedChange listener.

Answer 3

add this to recycleview adapter and you should be ok

 @Override
public int getItemViewType(int position) {
    return position;
}