利用RecyclerView实现图片新增、删除

删除** 新增

• 思路：

  1. 由于新增跟删除只是一个添加按钮跟CheckBox的区别，所以我们可以将两种情况分别用Adapter表示。
  2. 先定义删除的Adapter ， 重写getItemViewType方法，返回该Adapter的标识。
  3. 定义新增的Adapter，继承删除的Adapter，其布局只有一个ImageView（添加按钮）。
  4. 然后通过是否编辑模式，决定设置那种Adapter。

下面给出部分代码


  public class BaseHolder extends RecyclerView.ViewHolder {
  public View rootView;

      public BaseHolder(View itemView) {
          super(itemView);
          rootView = itemView;
      }
  }


  class PicAdapter extends RecyclerView.Adapter<BaseHolder> {
  private final int TYPE_ITEM = 0x00; //定义标识，标识是普通Item
  @Override
  public BaseHolder onCreateViewHolder(ViewGroup parent, int viewType) {
      View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.pic_album_item_view, parent, false);
      return new PicHolder(view);
  }

  @Override
  public void onBindViewHolder(final BaseHolder holder, int position) {
      holder.rootView.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View v) {
              //这里实现的是点击Item的处理逻辑
              Functions.toast(getApplicationContext(), holder.getLayoutPosition() + "");
          }
      });
      String image = images.get(position).getPicurl();
      PicHolder picHolder = (PicHolder) holder;
      picHolder.ivPicture.setImageResource(Functions.getResourceIdByString(image));
      if (isEditMode) {
          picHolder.cbSelectImg.setVisibility(View.VISIBLE);
      } else {
          picHolder.cbSelectImg.setVisibility(View.GONE);
      }
  }

  @Override
  public int getItemCount() {
      return images.size(); //返回集合size
  }

      @Override
      public int getItemViewType(int position) {
          return TYPE_ITEM; //返回普通Item的类型
      }

      class PicHolder extends BaseHolder {
          private ImageView ivPicture;
          private View view;
          private CheckBox cbSelectImg;

          public PicHolder(View itemView) {
              super(itemView);
              view = itemView;
              ivPicture = (ImageView) view.findViewById(R.id.ivPicture);
              cbSelectImg = (CheckBox) view.findViewById(R.id.cbSelectImg);
          }
      }
    }


  class AddPicAdapter extends PicAdapter {
  public final static int TYPE_ADD = 0x11; //定义添加Item的标识

  @Override
  public BaseHolder onCreateViewHolder(final ViewGroup parent, int viewType) {
      BaseHolder holder;
      //通过viewType判断加载那种布局
      if (viewType == TYPE_ADD) {
          View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.pic_album_add_item_view, parent, false);
          view.setOnClickListener(new View.OnClickListener() {

              //点击添加按钮的处理逻辑
              @Override
              public void onClick(View v) {
                  MovieMsgInfo info = new MovieMsgInfo();
                  Random random = new Random();
                  int result = random.nextInt(11) + 1;
                  info.setPicurl(PREIFX_DRAWABLE + result);
                  images.add(info);
                  mAdapter.notifyDataSetChanged();
              }
          });
          holder = new AddPicHolder(view);
          return holder;
      } else {
          return super.onCreateViewHolder(parent, viewType);
      }
  }

    @Override
    public void onBindViewHolder(BaseHolder holder, int position) {
        //通过判断是否点击最后一个Item
        if (position == getItemCount() - 1) {
            holder.rootView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    //点击最后添加按钮的处理逻辑
                }
            });

        } else {
            super.onBindViewHolder(holder, position);
        }
    }

    @Override
    public int getItemViewType(int position) {
        //根据position判断加载类型
        if (position == getItemCount() - 1) {
            return TYPE_ADD;
        }
        return super.getItemViewType(position);
    }


    @Override
    public int getItemCount() {
        //重中之重，返回Item数量为父类总数+1（+1是添加按钮）
        return super.getItemCount() + 1;
    }

    public class AddPicHolder extends BaseHolder {

        private ImageView ivPicture;

        public AddPicHolder(View itemView) {
            super(itemView);
            ivPicture = (ImageView) itemView.findViewById(R.id.ivPicture);
        }
    }

    }

HashSet控制集合选中以及取消

• 选中：点击的时候，将id加入到集合中
• 取消选择：判断是否包含该元素，是则删除，没有则添加。

onlick(){

  if(set.contain(user.getID())){
      set.remove(user.getID());
  }else{
      set.add(user.getId());
  }

}