FooterItemDecoration.java

import android.graphics.Canvas;
import android.graphics.Rect;
import android.view.View;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

public class FooterItemDecoration extends RecyclerView.ItemDecoration {
    private View footerView;

    public FooterItemDecoration(View footerView) {
        this.footerView = footerView;
    }

    @Override public void onDraw(@NonNull Canvas c, @NonNull RecyclerView parent,
            @NonNull RecyclerView.State state) {
        super.onDraw(c, parent, state);
        footerView.layout(parent.getLeft(), 0, parent.getRight(), footerView.getMeasuredHeight());
        for (int i = 0; i < parent.getChildCount(); i++) {
            View view = parent.getChildAt(i);
            if (parent.getChildAdapterPosition(view)
                    == parent.getLayoutManager().getItemCount() - 1) {
                c.save();
                c.translate(0f, view.getBottom());
                footerView.draw(c);
                c.restore();
                break;
            }
        }
    }

    @Override public void getItemOffsets(@NonNull Rect outRect, @NonNull View view,
            @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
        if (parent.getChildAdapterPosition(view) == parent.getLayoutManager().getItemCount() - 1) {
            footerView.measure(View.MeasureSpec.makeMeasureSpec(parent.getMeasuredWidth(),
                    View.MeasureSpec.AT_MOST),
                    View.MeasureSpec.makeMeasureSpec(parent.getMeasuredHeight(),
                            View.MeasureSpec.AT_MOST));
            outRect.set(0, 0, 0, footerView.getMeasuredHeight());
        } else {
            super.getItemOffsets(outRect, view, parent, state);
        }
    }
}

HeaderItemDecoration.java

import android.graphics.Canvas;
import android.graphics.Rect;
import android.view.View;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

public class HeaderItemDecoration extends RecyclerView.ItemDecoration {
    private View headerView;

    public HeaderItemDecoration(View headerView) {
        this.headerView = headerView;
    }

    @Override public void onDraw(@NonNull Canvas c, @NonNull RecyclerView parent,
            @NonNull RecyclerView.State state) {
        super.onDraw(c, parent, state);
        headerView.layout(parent.getLeft(), 0, parent.getRight(), headerView.getMeasuredHeight());
        for (int i = 0; i < parent.getChildCount(); i++) {
            View view = parent.getChildAt(i);
            if (parent.getChildAdapterPosition(view) == 0) {
                c.save();
                int height = headerView.getMeasuredHeight();
                int top = view.getTop() - height;
                c.translate(0f, top);
                headerView.draw(c);
                c.restore();
                break;
            }
        }
    }

    @Override public void getItemOffsets(@NonNull Rect outRect, @NonNull View view,
            @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
        if (parent.getChildAdapterPosition(view) == 0) {
            headerView.measure(View.MeasureSpec.makeMeasureSpec(parent.getMeasuredWidth(),
                    View.MeasureSpec.AT_MOST),
                    View.MeasureSpec.makeMeasureSpec(parent.getMeasuredHeight(),
                            View.MeasureSpec.AT_MOST));
            outRect.set(0, headerView.getMeasuredHeight(), 0, 0);
        } else {
            super.getItemOffsets(outRect, view, parent, state);
        }
    }
}