RecycleView 动画实现_onitemmovelistener-优快云博客

本文介绍如何在RecycleView中实现动画效果，并通过接口回调将onItemMove方法的实现置于具体的adapter中。详细步骤包括：1) 实现ItemDragHelperCallback；2) 在NewsChannelActivity.java中的应用；3) ChannelAdapter.java的改造。示例代码可在GitHub项目AndroidNews中查看。

文章http://blog.youkuaiyun.com/michael1112/article/details/53907868 描述了recycleView的原理。

本文章将动画进行了封装。用接口回调将onItemMove(int fromPosition, int toPosition) 的实现放到具体的adapter

1.实现 ItemDragHelperCallback

public class ItemDragHelperCallback extends ItemTouchHelper.Callback {
    private OnItemMoveListener mOnItemMoveListener;
    private boolean mIsLongPressEnabled;

    public void setLongPressEnabled(boolean longPressEnabled) {
        mIsLongPressEnabled = longPressEnabled;
    }

    public interface OnItemMoveListener {
        boolean onItemMove(int fromPosition, int toPosition);
    }

    public ItemDragHelperCallback(OnItemMoveListener onItemMoveListener) {
        mOnItemMoveListener = onItemMoveListener;
    }

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

    @Override
    public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
        int dragFlags = setDragFlags(recyclerView);
        int swipeFlags = 0;
        return makeMovementFlags(dragFlags, swipeFlags);
    }

    private int setDragFlags(RecyclerView recyclerView) {
        int dragFlags;
        RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
        if (layoutManager instanceof GridLayoutManager || layoutManager instanceof StaggeredGridLayoutManager) {
            dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN | ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
        } else {
            dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
        }
        return dragFlags;
    }

    @Override
    public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
        return !isDifferentItemViewType(viewHolder, target) &&
                mOnItemMoveListener.onItemMove(viewHolder.getAdapterPosition(), target.getAdapterPosition());

    }

    private boolean isDifferentItemViewType(RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
        return viewHolder.getItemViewType() != target.getItemViewType();
    }

    @Override
    public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
        super.clearView(recyclerView, viewHolder);

    }

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

    }
}

2.NewsChannelActivity.java

@Override
public void returnMineNewsChannels(List<NewsChannelTable> newsChannelsMine) {
    channelAdapterMine = new ChannelAdapter(mContext,R.layout.item_news_channel);
    newsChannelMineRv.setLayoutManager(new GridLayoutManager(this, 4, LinearLayoutManager.VERTICAL, false));
    newsChannelMineRv.setItemAnimator(new DefaultItemAnimator());
    newsChannelMineRv.setAdapter(channelAdapterMine);
    channelAdapterMine.replaceAll(newsChannelsMine);
    channelAdapterMine.setOnItemClickListener(new ChannelAdapter.OnItemClickListener() {
        @Override
        public void onItemClick(View view, int position) {
            NewsChannelTable newsChannel = channelAdapterMine.get(position);
                channelAdapterMore.add(newsChannel);
                channelAdapterMine.removeAt(position);
                mPresenter.onItemAddOrRemove((ArrayList<NewsChannelTable>) channelAdapterMine.getAll(), (ArrayList<NewsChannelTable>)channelAdapterMore.getAll());

        }
    });


    ItemDragHelperCallback itemDragHelperCallback = new ItemDragHelperCallback(channelAdapterMine);
    ItemTouchHelper itemTouchHelper = new ItemTouchHelper(itemDragHelperCallback);
    itemTouchHelper.attachToRecyclerView(newsChannelMineRv);
    channelAdapterMine.setItemDragHelperCallback(itemDragHelperCallback);
}

3..ChannelAdapter.java

public class ChannelAdapter  extends CommonRecycleViewAdapter<NewsChannelTable>implements
        ItemDragHelperCallback.OnItemMoveListener{

    private ItemDragHelperCallback mItemDragHelperCallback;
    private OnItemClickListener mOnItemClickListener;
    public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
        mOnItemClickListener = onItemClickListener;
    }

    public void setItemDragHelperCallback(ItemDragHelperCallback itemDragHelperCallback) {
        mItemDragHelperCallback = itemDragHelperCallback;
    }
    public ChannelAdapter(Context context, int layoutId) {
        super(context, layoutId);
    }

    @Override
    public void convert(ViewHolderHelper helper, NewsChannelTable newsChannelTable) {
        helper.setText(R.id.news_channel_tv,newsChannelTable.getNewsChannelName());
        if (newsChannelTable.getNewsChannelFixed()) {
            helper.setTextColor(R.id.news_channel_tv,ContextCompat.getColor(mContext,R.color.gray));
        }else{
            helper.setTextColor(R.id.news_channel_tv,ContextCompat.getColor(mContext,R.color.gray_deep));
        }
        handleLongPress(helper,newsChannelTable);
        handleOnClick(helper,newsChannelTable);
    }


    private void handleLongPress(ViewHolderHelper helper,final NewsChannelTable newsChannelTable) {
        if (mItemDragHelperCallback != null) {
            helper.itemView.setOnTouchListener(new View.OnTouchListener() {
                @Override
                public boolean onTouch(View v, MotionEvent event) {
                    mItemDragHelperCallback.setLongPressEnabled(newsChannelTable.getNewsChannelIndex()==0?false:true);
                    return false;
                }
            });
        }
    }

    private void handleOnClick(final ViewHolderHelper helper,final NewsChannelTable newsChannelTable) {
        if (mOnItemClickListener != null) {
            helper.itemView.setOnClickListener(new OnNoDoubleClickListener() {
                @Override
                protected void onNoDoubleClick(View v) {
                    if (!newsChannelTable.getNewsChannelFixed()) {
                        mOnItemClickListener.onItemClick(v, helper.getLayoutPosition());
                    }
                }
            });
        }
    }


    @Override
    public boolean onItemMove(int fromPosition, int toPosition) {
        if (isChannelFixed(fromPosition, toPosition)) {
            return false;
        }
        Collections.swap(getAll(), fromPosition, toPosition);
        notifyItemMoved(fromPosition, toPosition);
        RxBus.getInstance().post(AppConstant.CHANNEL_SWAP,new ChannelItemMoveEvent(fromPosition, toPosition));
        return true;
    }

    private boolean isChannelFixed(int fromPosition, int toPosition) {
        return (getAll().get(fromPosition).getNewsChannelFixed() ||
                getAll().get(toPosition).getNewsChannelFixed())&&(fromPosition==0||toPosition==0);
    }

    public interface OnItemClickListener {
        void onItemClick(View view, int position);
    }
}