How To Highlight Selected Item In RecyclerView

I have used RecyclerView for showing thumbnails in my Image Editing app.Each item of its comprises of a ImageView(thumbnail) and a textView.In my application I want to highlight on

Solution 1:

Just add this below line in bindView

holder.itemView.setBackgroundColor(Color.parseColor("#000000"));

will work for you.

if you want to highlight selected item just do like below

set it global

int selectedPosition=-1;

inside onBindViewHolder-

public void onBindViewHolder(FiltersAdapter.ViewHolder holder, int position) {
if(selectedPosition==position)
  holder.itemView.setBackgroundColor(Color.parseColor("#000000"));
else
  holder.itemView.setBackgroundColor(Color.parseColor("#ffffff"));

holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                selectedPosition=position;
                notifyDataSetChanged();

            }
        });
}

Solution 2:

Use background selector and set that in android:background property in the layout xml for the recyclerview item

background_selector.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="false" android:state_selected="true">
        <shape>
            <solid android:color="@color/lightPrimaryColor" />
        </shape>
    </item>

    <item android:state_selected="false">
        <shape>
            <solid android:color="@android:color/transparent" />
        </shape>
    </item>
</selector>

recyclerview_item.xml (background_selector is set in android:background property)

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/background_selector"
    android:orientation="vertical"
    android:paddingBottom="8dp"
    android:paddingLeft="16dp"
    android:paddingRight="16dp"
    android:paddingTop="8dp">

And then the place where you get the click event you can set it as selected with the View function

view.setSelected(true)

You would have to implement the logic for when you want to unselect/select the item by storing the position of selected items

Solution 3:

May be just use:

android:background="?attr/selectableItemBackground"

for root element at item xml?

Solution 4:

Create a Model CalenderModel name

class CalenderModel {
var date: String
var isselected: Boolean
constructor(date: String, isselected: Boolean) {
    this.date = date
    this.isselected = isselected
}
 }

Create a Adapter CalenderAdapter name

class CalenderAdapter(
internal var activity: Activity,
internal var calenderModelList: ArrayList<CalenderModel>
) : RecyclerView.Adapter<CalenderAdapter.MyViewHolder>() {
var selected_defoult = 0
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
    val itemView: View
    itemView =
        LayoutInflater.from(parent.context).inflate(R.layout.item_calenderdate, 
parent, false)
    return MyViewHolder(itemView)
}

override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
    val list = calenderModelList.get(position)
    holder.date_tv.text = Common.formateDate_calender_date(list.date)
    holder.day_tv.text = Common.formateDate_calender_day(list.date)
    if (position <= 3) {
        if (list.isselected) {
            holder.mLinearLayout.setBackgroundDrawable(
                ContextCompat.getDrawable(
                    activity,
                    R.drawable.selected_calender_background_green
                )
            )
        } else {
            holder.mLinearLayout.setBackgroundDrawable(
                ContextCompat.getDrawable(
                    activity,
                    R.drawable.selected_calender_background_gray
                )
            )
        }
    } else {
        holder.mLinearLayout.setBackgroundDrawable(
            ContextCompat.getDrawable(
                activity,
                R.drawable.selected_calender_background_gray_light
            )
        )
    }

    holder.itemView.setOnClickListener {
        if (position <= 3) {
            calenderModelList.get(selected_defoult).isselected = false
            calenderModelList.get(position).isselected = true
            selected_defoult = position
            notifyDataSetChanged()
        }
    }

   }

 override fun getItemCount(): Int {
    return calenderModelList.size
 }

override fun getItemId(position: Int): Long {
    return position.toLong()
}

override fun getItemViewType(position: Int): Int {
    return position
}


inner class MyViewHolder
internal constructor(itemView: View) : RecyclerView.ViewHolder(itemView) {

    val day_tv: TextView
    val date_tv: TextView
    val mLinearLayout: LinearLayout

    init {
        mLinearLayout = itemView.findViewById(R.id.mLinearLayout)
        day_tv = itemView.findViewById(R.id.day_tv)
        date_tv = itemView.findViewById(R.id.date_tv)

    }
 }


 }

Solution 5:

update your enum to class first for flag

public class Type {
    public int type; // 0-Original,1-Grayscale,2-Sepia.... same as enum
    public int selected;
}

now in adapter

@Override
public void onBindViewHolder(FiltersAdapter.ViewHolder holder, int position) {
    int typeOfItem = mDataSet.get(position).type
    switch (mDataSet.get(position)) {
        case 0:
            holder.image.setImageResource(R.drawable.no_filter);
            break;
        case 1:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new GrayscaleTransformation())
                    .into(holder.image);
            break;
        case 2:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new SepiaFilterTransformation(mContext))
                    .into(holder.image);
            break;
        case 3:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new ContrastFilterTransformation(mContext, 2.0f))
                    .into(holder.image);
            break;
        case 4:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new InvertFilterTransformation(mContext))
                    .into(holder.image);
            break;
        case 5:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new PixelationFilterTransformation(mContext, 20))
                    .into(holder.image);
            break;
        case 6:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new SketchFilterTransformation(mContext))
                    .into(holder.image);
            break;
        case 7:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new SwirlFilterTransformation(mContext, 0.5f, 1.0f, new PointF(0.5f, 0.5f)))
                    .into(holder.image);
            break;
        case 8:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new BrightnessFilterTransformation(mContext, 0.5f))
                    .into(holder.image);
            break;
        case 9:
            Picasso.with(mContext)
                    .load(R.drawable.no_filter)
                    .transform(new VignetteFilterTransformation(mContext, new PointF(0.5f, 0.5f),
                            new float[]{0.0f, 0.0f, 0.0f}, 0f, 0.75f))
                    .into(holder.image);
            break;
        default:
            holder.image.setImageResource(R.drawable.no_filter);
            break;
    }
    holder.title.setText(mDataSet.get(position).name());
    if(mDataSet.get(position).selected == 0){
        holder.title.setTypeface(null, Typeface.BOLD);
    } else {
        holder.title.setTypeface(null,Typeface.NORMAL);
    }
}

not on every click or select update your list then call notifydatasetChanged() of adapter