160405A(화)

Drag and Swipe with RecyclerView

ItemTouchHelper

매우 강력한 유틸리티

drag & drop 

swipe-to-dismiss

ItemTouchHelper.Callback

interface

move 와 swipe 이벤트를 listen

이렇게 Callback 클래스를 만들어서 사용한다.

public class ActiconSettingTouchHelper extends ItemTouchHelper.SimpleCallback {
   private ActiconSettingRecyclerViewAdapter mAdapter;

   public ActiconSettingTouchHelper(ActiconSettingRecyclerViewAdapter adapter) {
      super(ItemTouchHelper.UP | ItemTouchHelper.DOWN, ItemTouchHelper.DOWN | ItemTouchHelper.UP);
      this.mAdapter = adapter;
   }

   @Override
   public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
      mAdapter.swap(viewHolder.getAdapterPosition(), target.getAdapterPosition());

      return true;
   }

   @Override
   public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {

   }

   @Override
   public boolean isLongPressDragEnabled() {
      return false;
   }

   @Override
   public boolean isItemViewSwipeEnabled() {
      return false;
   }

롱클릭이 아니라 특정 뷰에 대해서 drag되게 하려면 interface를 Adapter에 선언하여 Activity나 Fragment에 전달한다.

public void swap(int firstPosition, int secondPosition) {
   Collections.swap(mActiconGroupList, firstPosition, secondPosition);
   notifyItemMoved(firstPosition, secondPosition);
}

public interface onDragStartListener {
   void onDragStarted(RecyclerView.ViewHolder viewHolder);
}

@Override
public void onBindViewHolder(final ActiconSettingRecyclerViewHolder holder, int position) {
   ActiconGroupData data = mActiconGroupList.get(position);
   downloadImage(data, holder.mActiconThumb);

   holder.mActiconName.setText(mActiconGroupList.get(position).productNm);

   holder.mActiconDragLayout.setOnTouchListener(new View.OnTouchListener() {

      @Override
      public boolean onTouch(View v, MotionEvent event) {
         if (MotionEventCompat.getActionMasked(event) == MotionEvent.ACTION_DOWN) {
            mDragStartListener.onDragStarted(holder);
         }

         return false;
      }
   });
}

Activity에서는 다음과 같이 선언하여 attach한다.

private void setItemTouchHelper() {
   callback = new ActiconSettingTouchHelper(mSettingAdapter);
   helper = new ItemTouchHelper(callback);
   helper.attachToRecyclerView(mRecyclerView);
}

@Override
public void onDragStarted(RecyclerView.ViewHolder viewHolder) {
   helper.startDrag(viewHolder);
}