android - RecyclerView laggy scrolling

Question

I am loading 400x200 images in RecyclerView, but scrolling is laggy on 2k devices. I am using Picasso for loading images from resource.

As you can see in the demo images are blurry on 2k screen, but if I load higher resolution images the situation gets worse. How to fix this, I am not even loading large image, its 400x200 ?

Demo

Here is my code card_view.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:id="@+id/card_view"
    card_view:cardPreventCornerOverlap="false"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_margin="8dp"
    card_view:cardCornerRadius="2dp">

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:id="@+id/rel">

        <ImageView
            android:id="@+id/cardimage"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:scaleType="fitXY"
            android:src="@drawable/p7"/>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="title"
            android:paddingLeft="16dp"
            android:paddingRight="16dp"
            android:paddingTop="16dp"
            android:paddingBottom="24dp"
            android:textStyle="bold"
            android:textSize="24sp"
            android:id="@+id/cardtitle"
            android:layout_gravity="center_vertical"/>

    </LinearLayout>

</android.support.v7.widget.CardView>

Myadapter Code

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

private Context mContext;
List<Flower> list = new ArrayList<>();

public CardAdapter(Context mContext, List<Flower> list) {
    this.mContext = mContext;
    this.list = list;

}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)   {

    View itemView = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.card_view, parent, false);
    return new ViewHolder(itemView);
}

@Override
public void onBindViewHolder(ViewHolder holder, int position)  {

    holder.Flower=getItem(position);
    holder.cardtitle.setText(list.get(position).name);

    Picasso.with(mContext)
            .load(list.get(position).id)
            .placeholder(R.drawable.ic_launcher)
            .into(holder.cardimage);
}

@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
    super.onAttachedToRecyclerView(recyclerView);
}

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

public Flower getItem(int i) {
    return list.get(i);
}

public class ViewHolder extends RecyclerView.ViewHolder {

    ImageView cardimage;
    TextView cardtitle;
    Flower Flower;

    public ViewHolder(View itemView) {
        super(itemView);

        cardimage = (ImageView) itemView.findViewById(R.id.cardimage);
        cardtitle = (TextView) itemView.findViewById(R.id.cardtitle);
    }
}
}

UPDATE: I am loading images from resource, I am not downloading nothing

Here is my array

 private void initializeData() {
    flowers = new ArrayList<>();
    flowers.add(new Flower("Flower 1", R.drawable.p8));
    flowers.add(new Flower("Flower 2", R.drawable.p10));
    flowers.add(new Flower("Flower 3", R.drawable.p11));
    flowers.add(new Flower("Flower 4", R.drawable.p8));
    flowers.add(new Flower("Flower 5", R.drawable.photo2));
    flowers.add(new Flower("Flower 6", R.drawable.photo6));
    flowers.add(new Flower("Flower 7", R.drawable.p12));
    flowers.add(new Flower("Flower 8", R.drawable.p9));
    flowers.add(new Flower("Flower 9", R.drawable.p8));
    flowers.add(new Flower("Flower 10", R.drawable.p8));
    flowers.add(new Flower("Flower 11", R.drawable.p8));
    flowers.add(new Flower("Flower 12", R.drawable.p10));
}

UPDATE 2 : Guys I fixed most of the lag by setting adapter.setHasStableIds(true) , but app is still laggy on the first scroll while images are not loaded yet, how to fix that ?

UPDATE 3: I just tried loading images from web and everything seems smooth, probably there is some problem with loading images from resource .

Ok, thank you guys, I am gonna load my images from web.

Answer 1

if you are using two or more recycler views like (RecyclerView and NestedView) try this

recyclerView.setNestedScrollingEnabled(false);

Source : Recyclerview inside Nested Scrollview scroll but does not fast scroll like normal Recyclerview or Nested Scrollview