如何在recyclerview内的特定位置添加分隔符？

Question

I have a list of taskLists. To show the list I have used recyclerview. I have 1st 3 items as today , tomorrow and later in my list. I want to add one separator after 1st 3 items in recycler view. How can I do this?

Adapter :

    public class ListAdapter extends RecyclerView.Adapter<ListAdapter.ItemViewHolder>{

    ArrayList<ListData> item;
    public static final int TYPE1=1;
    Context conext;


  public   ListAdapter(Context context, ArrayList<ListData> item) {
        this.conext=context;
        this.item=item;

    }
    public interface OnItemClickListener {
        void onItemClick(ListData listData);
    }
    @Override
    public int getItemCount() {
        return item.size();

    }
    public void remove(int position) {
        item.remove(position);
        notifyItemRemoved(position);
    }

   // @Override
   // public int getItemViewType(int position) {
       // return item.get(position).getExpenseType();// Assume that this return 1 0r 2
  //  }

    @Override
    public void onBindViewHolder(ItemViewHolder itemViewHolder,final int i) {

        itemViewHolder.listName.setText(item.get(i).getTitle());

    }

    @Override
    public ItemViewHolder onCreateViewHolder(ViewGroup viewGroup,int viewType) {

        View itemView = LayoutInflater.
                from(viewGroup.getContext()).
                inflate(R.layout.list_layout, viewGroup, false);
        return new ItemViewHolder(itemView,viewType);

    }


    public static class ItemViewHolder extends RecyclerView.ViewHolder {

        TextView listName;


        ItemViewHolder(View itemView, int viewType) {
            super(itemView);

            listName  = (TextView)itemView.findViewById(R.id.listData);

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

}

Can anyone help with this how can I put separator after 3 items in list? Thank you..

Answer 1

You should define 2 types of RecyclerView rows:

...YourRecyclerAdapter extends RecyclerView.Adapter<BaseViewHolder>

public static final int COMMON = 1;
public static final int SEPARATOR = 2;

Override getItemViewType method of your Adapter :

@Override
public int getItemViewType(int position) {
    if (position%10 == 0) //each 10 row is separator (change it!)
        return SEPARATOR;
    else return COMMON;
}

Change onCreateViewHolder method of your Adapter :

@Override
public BaseViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    if (viewType == COMMON)
        return new ItemViewHolder(LayoutInflater.from(activity).inflate(R.layout.list_layout, parent, false));
    else
        return new SeparatorHolder(LayoutInflater.from(activity).inflate(R.layout.separator_item, parent, false));
}

@Override
public void onBindViewHolder(BaseViewHolder holder, int position) {
     if (getItemViewType(position) == COMMON) {
          //do stuff
     } else {
     }
}

---

ItemViewHolder extends BaseViewHolder
SeparatorHolder extends BaseViewHolder
BaseViewHolder extends RecyclerView.ViewHolder

Answer 2

You can create two ViewHolder class and Switch them in onCreateViewHolder . One containing your custom line, and others as your custom list items.

   class ViewHolderLine extends RecyclerView.ViewHolder { //contains line
    }

    class ViewHolderItems extends RecyclerView.ViewHolder { //contains data
    }

  @Override
   public int getItemViewType(int position) {
        return item.get(position).getExpenseType();// Assume that this return 1 0r 2
   }

  @Override
    public ItemViewHolder onCreateViewHolder(ViewGroup viewGroup,int viewType) {

       switch (viewType) {
         case 1: return new ViewHolderLine();
         case 2:
             View itemView = LayoutInflater.
            from(viewGroup.getContext()).
            inflate(R.layout.list_layout, viewGroup, false);
            return new ItemViewHolder(itemView,viewType);
         }


  }

You can see the details description here for more info.

Answer 3

One solution is define 2 types of RecyclerView rows (one for normal row and one for separator) Another solution is you should a Separator View in the bottom of your custom RecycleView row xml

<View
    android:id="@+id/separatorView"
    android:layout_width="match_parent"
    android:layout_height="3dp"
    android:visible="gone"
    android:background="@android:color/darker_gray"/>

Then in bindViewHolder of your RecyclerView.Adapter , hide the separator in normal row and visible it in separator row

 @Override
    public void bindViewHolder(ViewHolder holder, int position) {
        if(position == separatorPosition){
           holder.separatorView.visible = View.VISIBLE;
        }else{
           holder.separatorView.visible = View.GONE;
        }
    }

Hope this help

Answer 4

if you know that you are only going to add separator in the 1st three items, then you can put a condition based on the position of the item, inside onBindViewHolder .

ps: Please do not forget to add an else block after an if block

Answer 5

I have a recyclerview with section header and variable number of items in each section. The section should have a line separator across entire screen. and items must have a padded line between them. So, my solution(in kotlin) was having two viewholders, one for header and one for item. in getItemViewType, return the type based on the item.

override fun getItemViewType(position: Int): Int {
    if(dataList[position] is HeaderItem)
        return Companion.TYPE_HEADER
    return Companion.TYPE_ITEM
   }

and create the corresponding viewholder in createviewholder, bind accordingly.

Used

parent.getChildViewHolder(parent.getChildAt(i))

to decide the padding(or color or width) for the item separator.

class ItemDivider(context: Context) : RecyclerView.ItemDecoration() {
    private var mDivider: Drawable
    private val mContext = context
companion object {
    private val ATTRS = intArrayOf(android.R.attr.listDivider)
}

init {
    val styledAttributes = context.obtainStyledAttributes(ATTRS)
    mDivider = styledAttributes.getDrawable(0)
    mDivider.setTint(ContextCompat.getColor(mContext, <color>))
    styledAttributes.recycle()
}

override fun onDraw(c: Canvas, parent: RecyclerView, state: RecyclerView.State?) {
    val right = parent.width - parent.paddingRight

    for (i in 0 until parent.childCount - 1) {
        val child = parent.getChildAt(i)
        val params = child.layoutParams as RecyclerView.LayoutParams
        val left = if (parent.getChildViewHolder(child) is HeaderViewHolder) {
            0
        } else {
            child.left + params.leftMargin + mContext.resources.getDimension(<padding_in_dp>).toInt()
        }
        val top = child.bottom + params.bottomMargin
        val bottom = top + mDivider.intrinsicHeight + <divider_height>

        mDivider.setBounds(left, top, right, bottom)
        mDivider.draw(c)
    }
}
}

remember to replace the color, padding, divider height with valid values.

Hope it helps!