Changing background color of selected item in recy

Question

How to change the background color of only selected view in my recycle view example?only the background color of clicked itemview needs to be changed. Only one selected item must be displayed with background color change at a time and the rest needs to be as before selecting. here is my code :

MainActivity

public class MainActivity extends AppCompatActivity {
RecyclerView rv1;
    private  final String android_versions[]={
                "Donut",
                "Eclair",
                "Froyo",
                "Gingerbread",
                "Honeycomb",
                "Ice Cream Sandwich",
                "Jelly Bean",
                "KitKat",
                "Lollipop",
                "Marshmallow"
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initViews();
    }

    private  void initViews(){
        rv1=(RecyclerView)findViewById(R.id.recyclerView1);
        rv1.setHasFixedSize(true);
        RecyclerView.LayoutManager layoutManager=new LinearLayoutManager(getApplicationContext());
        rv1.setLayoutManager(layoutManager);

        RecyclerDataAdapter rda=new RecyclerDataAdapter(rv1,getApplicationContext(),android_versions);
        rv1.setAdapter(rda);
    }
}

RecyclerDataadapter

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

private String android_versionnames[];
    private Context context1;

    private RecyclerView mRecyclerView;


    public RecyclerDataAdapter(RecyclerView recylcerView,Context context,String android_versionnames[]){
        this.android_versionnames=android_versionnames;
        this.context1=context;
mRecyclerView=recylcerView;
        setHasStableIds(true);
        System.out.println("Inside dataadapter,Android names : \n ");
        for(int i=0;i<android_versionnames.length;i++){
            System.out.println("\n"+android_versionnames[i]);
        }
    }


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

    @Override
    public void onBindViewHolder(final ViewHolder holder, int position) {
        holder.tv1.setText(android_versionnames[position]);
    }


    @Override
    public int getItemCount() {
        return android_versionnames.length;
    }


    public class ViewHolder extends RecyclerView.ViewHolder {
        private TextView tv1;
        LinearLayout row_linearlayout;
        RecyclerView rv2;

        public ViewHolder(final View itemView) {
            super(itemView);
            tv1=(TextView)itemView.findViewById(R.id.txtView1);
            row_linearlayout=(LinearLayout)itemView.findViewById(R.id.row_linrLayout);
            rv2=(RecyclerView)itemView.findViewById(R.id.recyclerView1);
            /*itemView.setBackgroundColor(0x00000000);//to transparent*/

        }
    }
}

Answer 1

Most Simpler Way From My Side is to Add a variable in adapterPage as last Clicked Position.

in onBindViewHolder paste this code which checks for last stored position matched with loading positions Constants is the class where i declare my global variables

if(Constants.LAST_SELECTED_POSITION_SINGLE_PRODUCT == position) {

    //change the view background here
    holder.colorVariantThumb.setBackgroundResource(R.drawable.selected_background);
}

//on view click you store the position value and notifyItemRangeChanged will 
// call the onBindViewHolder and will check the condition

holder.itemView.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view){
        Constants.LAST_SELECTED_POSITION_SINGLE_PRODUCT=position;
        notifyItemRangeChanged(0, mColorVariants.size());
    } 
});

Answer 2

What I did to achieve this was actually taking a static variable to store the last clicked position of the item in the RecyclerView and then notify the adapter to update the layout at the position on the last clicked position i.e. notifyItemChanged(lastClickedPosition) whenever a new position is clicked. Calling notifyDataSetChanged() on the whole layout is very costly and unfeasible so doing this for only one position is much better.

Here's the code for this:

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

private String android_versionnames[];
private Context mContext;
private static lastClickedPosition = -1; // Variable to store the last clicked item position


    public RecyclerDataAdapter(Context context,String android_versionnames[]){
        this.android_versionnames = android_versionnames;
        this.mContext = context;
        }
    }


    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(mContext).inflate(R.layout.row_layout,
                parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(final ViewHolder holder, int position) {
        holder.tv1.setText(android_versionnames[position]);    
        holder.itemView.setBackgroundColor(mContext.getResources().
        getColor(R.color.cardview_light_background));
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {                    
            v.setBackgroundColor(mContext.getResources().
            getColor(R.color.dark_background));
                if (lastClickedPosition != -1)
                    notifyItemChanged(lastClickedPosition);
                lastClickedPosition = position;
            }
        });
    }


    @Override
    public int getItemCount() {
        return android_versionnames.length;
    }


    public class ViewHolder extends RecyclerView.ViewHolder {
        private TextView tv1;

        public ViewHolder(final View itemView) {
            super(itemView);
            tv1=(TextView)itemView.findViewById(R.id.txtView1);
        }
    }
}

So we will be actually updating only the intended item and not re-running unnecessary updates to the items which have not even been changed.

Answer 3

Finally, I got the answer.

public void onBindViewHolder(final ViewHolder holder, final int position) {
        holder.tv1.setText(android_versionnames[position]);

        holder.row_linearlayout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                row_index=position;
                notifyDataSetChanged();
            }
        });
        if(row_index==position){
            holder.row_linearlayout.setBackgroundColor(Color.parseColor("#567845"));
            holder.tv1.setTextColor(Color.parseColor("#ffffff"));
        }
        else
        {
            holder.row_linearlayout.setBackgroundColor(Color.parseColor("#ffffff"));
            holder.tv1.setTextColor(Color.parseColor("#000000"));
        }

    }

here 'row_index' is set as '-1' initially

public class ViewHolder extends RecyclerView.ViewHolder {
        private TextView tv1;
        LinearLayout row_linearlayout;
        RecyclerView rv2;

        public ViewHolder(final View itemView) {
            super(itemView);
            tv1=(TextView)itemView.findViewById(R.id.txtView1);
            row_linearlayout=(LinearLayout)itemView.findViewById(R.id.row_linrLayout);
            rv2=(RecyclerView)itemView.findViewById(R.id.recyclerView1);
        }
    }

Answer 4

My solution:

public static class SimpleItemRecyclerViewAdapter
        extends RecyclerView.Adapter<SimpleItemRecyclerViewAdapter.ViewHolder> {

    private final MainActivity mParentActivity;
    private final List<DummyContent.DummyItem> mValues;
    private final boolean mTwoPane;
    private static int lastClickedPosition=-1;
    **private static View viewOld=null;**
    private final View.OnClickListener mOnClickListener = new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            DummyContent.DummyItem item = (DummyContent.DummyItem) view.getTag();
            if (mTwoPane) {
                Bundle arguments = new Bundle();
                arguments.putString(ItemDetailFragment.ARG_ITEM_ID, item.id);
                ItemDetailFragment fragment = new ItemDetailFragment();
                fragment.setArguments(arguments);
                mParentActivity.getSupportFragmentManager().beginTransaction()
                        .replace(R.id.item_detail_container, fragment)
                        .commit();
            } else {
                Context context = view.getContext();
                Intent intent = new Intent(context, ItemDetailActivity.class);
                intent.putExtra(ItemDetailFragment.ARG_ITEM_ID, item.id);

                context.startActivity(intent);
            }

            **view.setBackgroundColor(mParentActivity.getResources().getColor(R.color.SelectedColor));
            if(viewOld!=null)
                viewOld.setBackgroundColor(mParentActivity.getResources().getColor(R.color.DefaultColor));
            viewOld=view;**
        }
    };

viewOld is null at the beginning, then points to the last selected view. With onClick you change the background of the selected view and redefine the background of the penultimate view selected. Simple and functional.

Answer 5

Create Drawable file in Drawable foloder

<item android:drawable="@color/SelectedColor" android:state_pressed="true"></item>
<item android:drawable="@color/SelectedColor" android:state_selected="true"></item>
<item android:drawable="@color/DefultColor"></item>

And in xml file

android:background="@drawable/Drawable file"

In RecyclerView onBindViewHolder

holder.button.setSelected(holder.button.isSelected()?true:false);

Like toggle button

Answer 6

I managed to do this from my Activity where i'm setting my Rv and not from the adapter

If someone need to do something similar here's the code

In this case the color changes on a logClick

           @Override
        public void onLongClick(View view, int position) {
            Toast.makeText(UltimasConsultasActivity.this, "Item agregado a la lista de mails",
                    Toast.LENGTH_SHORT).show();

            sendMultipleMails.setVisibility(View.VISIBLE);
            valueEmail.setVisibility(View.VISIBLE);
            itemsSeleccionados.setVisibility(View.VISIBLE);

            listaEmails.add(superListItems.get(position));
            listaItems ="";
            NameOfyourRecyclerInActivity.findViewHolderForAdapterPosition(position).NameOfYourViewInTheViewholder.setBackgroundColor((Color.parseColor("#336F0D")));

            for(int itemsSelect = 0; itemsSelect <= listaEmails.size() -1; itemsSelect++){

             listaItems  +=  "*"+listaEmails.get(itemsSelect).getDescripcion() + "\n";
            }

            itemsSeleccionados.setText("Items Seleccionados : "+  "\n" + listaItems);


        }


    }));