android 瀑布流布局 + 自由拖拽

首先，确定使用RecyclerView
我们需要 导包 把

 compile 'com.android.support:recyclerview-v7:25.3.0'

加入dependencies
定义适配器

MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.ViewHolder>{ public TextView item_info;        public TextView item_title;        public ImageView imageView;        public ViewHolder(View view) {            super(view);            //item_title = (TextView) view.findViewById(R.id.title_1);           // item_info = (TextView) view.findViewById(R.id.info_1);            imageView = (ImageView) view.findViewById(R.id.sample_icon);        }        }

在MyRecyclerViewAdapter中定义内部类

 //自定义的ViewHolder，持有每个Item的的所有界面元素    public static class ViewHolder extends RecyclerView.ViewHolder

由于RecyclerView不再负责Item视图的布局及显示，所以RecyclerView也没有为Item开放OnItemClick等点击事件，这就需要开发者自己实现。

//define interface    public static interface OnRecyclerViewItemClickListener {        void onItemClick(View view , Object object);    }     @Override    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        View view = mInflater.inflate(R.layout.recycler_item, parent, false);        view.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                if (mOnItemClickListener != null) {                    //注意这里使用getTag方法获取数据                    mOnItemClickListener.onItemClick(v,v.getTag());                }            }        });        ViewHolder viewHolder = new ViewHolder(view);        return viewHolder;    } /**     * 数据的绑定显示     *     * @param holder     * @param position     */    @Override    public void onBindViewHolder(ViewHolder holder, int position) { //to do bind view//把数据绑到每个itemView上；        holder.itemView.setTag(mData.get(position));}        @Override    public int getItemCount() {        return mData.size();    }

在MainActivity onCreate

mTitles = new ArrayList();        final RecyclerView recview = (RecyclerView) findViewById(R.id.recview);        adapter = new MyRecyclerViewAdapter(this,mTitles);        adapter.setOnItemClickListener(new MyRecyclerViewAdapter.OnRecyclerViewItemClickListener() {            @Override            public void onItemClick(View view, Object object) {                Log.e("onItemClick",object+"");            }        });        // LinearLayoutManager layoutManager = new LinearLayoutManager(this);         // GridLayoutManager layoutManager=new GridLayoutManager(this,2);       // StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(2,       //         StaggeredGridLayoutManager.HORIZONTAL);        StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(                3,                StaggeredGridLayoutManager.VERTICAL);        //设置布局管理器        ItemTouchHelper helper = new ItemTouchHelper(new ItemTouchHelperCallback(mTitles,adapter));        helper.attachToRecyclerView(recview);        recview.setLayoutManager(layoutManager);        recview.setAdapter(adapter);

定义接口

public interface ItemTouchHelperViewHolder {    /**     * 当Item开始拖拽或者滑动的时候调用     */    void onItemSelected();    /**     * 当Item完成拖拽或者滑动的时候调用     */    void onItemClear();}

让上面的ViewHolder去实现 就可以根据情况改变

 public static class ViewHolder extends RecyclerView.ViewHolder implements ItemTouchHelperViewHolder 

定义ItemTouchHelperCallback

public class ItemTouchHelperCallback extends ItemTouchHelper.Callback {    private List mData;    private RecyclerView.Adapter adapter;    public ItemTouchHelperCallback(List mData, RecyclerView.Adapter adapter) {        this.mData = mData;        this.adapter = adapter;    }    @Override    public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {        //首先回调的方法 返回int表示是否监听该方向        int dragFlags = ItemTouchHelper.UP|ItemTouchHelper.DOWN|ItemTouchHelper.LEFT|ItemTouchHelper.RIGHT;//拖拽        int swipeFlags = 0 ;//侧滑删除        return makeMovementFlags(dragFlags,swipeFlags);    }    @Override    public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {        //滑动事件        Collections.swap(mData,viewHolder.getAdapterPosition(),target.getAdapterPosition());        adapter.notifyItemMoved(viewHolder.getAdapterPosition(),target.getAdapterPosition());        return false;    }    @Override    public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {        //侧滑事件       // mData.remove(viewHolder.getAdapterPosition());       // adapter.notifyItemRemoved(viewHolder.getAdapterPosition());    }    @Override    public boolean isLongPressDragEnabled() {        //是否可拖拽        return true;    }    /**     * 当拖拽开始的时候调用     *     * @param viewHolder     * @param actionState     */    @Override    public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {        //拖拽的时候         if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {            if (viewHolder instanceof ItemTouchHelperViewHolder) {                //让ViewHolder知道Item开始选中                ItemTouchHelperViewHolder itemViewHolder = (ItemTouchHelperViewHolder) viewHolder;                //回调ItemTouchHelperVIewHolder的方法                itemViewHolder.onItemSelected();            }        }        super.onSelectedChanged(viewHolder, actionState);    }    /**     * 当拖拽结束的时候调用     *     * @param recyclerView     * @param viewHolder     */    @Override    public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {        super.clearView(recyclerView, viewHolder);        if (viewHolder instanceof ItemTouchHelperViewHolder) {            ItemTouchHelperViewHolder itemViewHolder = (ItemTouchHelperViewHolder) viewHolder;            //Item移动完成之后的回调            itemViewHolder.onItemClear();        }    }}