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AndroidRecyclerView上拉加载更多功能回弹实现代码

实现原理是使用RecyclerView的OnTouchListener方法监听滑动 在adapter里面增加两项footview 其中date.size为显示的加载条，可以自定义，date.size+1为空白的View，我们设置其高度为0 我们通过LinearLayoutManager的 findLastVisibleItemPosition判断显示的最后一条数据，如果是空白view，表示加载条已经完全展示，松开即可刷新。

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回弹效果是通过在滑动时动态改变空白view的高度，达到阻尼效果 ，回弹时再动态将其改为0，达到回弹效果，通过loading防止加载过程中滑动导致显示问题 这里的回调采用了Runnable传参

public class RefreshFootAdapter extends 
    RecyclerView.Adapter { 
  // 上拉加载更多 
  public static final int SATUS_PULLUP_LOAD_MORE = 0; 
  // 正在加载中 
  public static final int SATUS_LOADING_MORE = 1; 
  public static final int SATUS_UP_LOADING_MORE = 2; 
  // 上拉加载更多状态-默认为0 
  private int load_more_status = 0; 
  private LayoutInflater mInflater; 
  private List mTitles = null; 
  private static final int TYPE_ITEM = 0; // 普通Item View 
  private static final int TYPE_FOOTER = 1; // 底部FootView 
  private static final int TYPE_FOOTER_EMPTY = 2; // 底部空白View 
  private static int pagesize; 
  private int eview_height = 1; 
  private long TimeFlag;// 回弹时间 
  private RecyclerView parent; 
  private boolean loadmare;// 判断当前是可加载更多 
  private boolean loading;// 判断是否正在加载 
  private int startY, nowY;// 滑动判断 
 //构造函数 处理滑动监听 更新等功能 
  public RefreshFootAdapter(Context context, RecyclerView parent, 
      final LinearLayoutManager linearLayoutManager, int pagesize, 
      final Runnable onloadmore) { 
    this.parent = parent; 
    this.mInflater = LayoutInflater.from(context); 
    this.mTitles = new ArrayList(); 
    for (int i = 0; i < 20; i++) { 
      int index = i + 1; 
      mTitles.add("item" + index); 
    } 
    this.pagesize = pagesize; 
    parent.setOnTouchListener(new OnTouchListener() { 
      @Override 
      public boolean onTouch(View v, MotionEvent ev) { 
        // TODO Auto-generated method stub 
        switch (ev.getAction()) { 
        case MotionEvent.ACTION_MOVE: 
          nowY = (int) ev.getY(); 
          if (RefreshFootAdapter.this.getItemCount() == linearLayoutManager 
              .findLastVisibleItemPosition() + 1) { 
            if (startY == 0) {// 按下 
              startY = nowY; 
            } 
            int changeY = nowY - startY; 
            RefreshFootAdapter.this 
                .notifyEmptyView((int) (-changeY / 1.3f)); 
            if (loading) { 
              return false; 
            } 
            RefreshFootAdapter.this 
                .changeMoreStatus(RefreshFootAdapter.this.SATUS_UP_LOADING_MORE); 
            loadmare = true; 
          } else { 
            loadmare = false; 
            if (loading) { 
              return false; 
            } 
            RefreshFootAdapter.this 
                .changeMoreStatus(RefreshFootAdapter.this.SATUS_PULLUP_LOAD_MORE); 
            // 普通的滑动 
            startY = 0; 
          } 
          break; 
        case MotionEvent.ACTION_UP: 
          RefreshFootAdapter.this.resetEmptyView(); 
          if (loadmare) { 
            if (loading) { 
              return false; 
            } else { 
              RefreshFootAdapter.this 
                  .changeMoreStatus(RefreshFootAdapter.this.SATUS_LOADING_MORE); 
              if (onloadmore != null && !loading) { 
                loading = true; 
                onloadmore.run(); 
              } 
            } 
          } 
          startY = 0; 
          break; 
        default: 
          break; 
        } 
        return false; 
      } 
    }); 
  } 
  /** 
   * item显示类型 
   * 
   * @param parent 
   * @param viewType 
   * @return 
   */ 
  public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, 
      int viewType) { 
    // 进行判断显示类型，来创建返回不同的View 
    if (viewType == TYPE_ITEM) { 
      View view = mInflater.inflate(R.layout.item_recycler_layout, 
          parent, false); 
      // 这边可以做一些属性设置，甚至事件监听绑定 
      // view.setBackgroundColor(Color.RED); 
      ItemViewHolder itemViewHolder = new ItemViewHolder(view); 
      return itemViewHolder; 
    } else if (viewType == TYPE_FOOTER) { 
      View foot_view = mInflater.inflate( 
          R.layout.recycler_load_more_layout, parent, false); 
      // 这边可以做一些属性设置，甚至事件监听绑定 
      // view.setBackgroundColor(Color.RED); 
      FootViewHolder footViewHolder = new FootViewHolder(foot_view); 
      return footViewHolder; 
    } else if (viewType == TYPE_FOOTER_EMPTY) { 
      View foot_view_empty = mInflater.inflate( 
          R.layout.recycler_load_more_layout_empty, parent, false); 
      // 这边可以做一些属性设置，甚至事件监听绑定 
      // view.setBackgroundColor(Color.RED); 
      FootEmptyHolder footEmptyViewHolder = new FootEmptyHolder( 
          foot_view_empty); 
      return footEmptyViewHolder; 
    } 
    return null; 
  } 
  /** 
   * 数据的绑定显示 
   * 
   * @param holder 
   * @param position 
   */ 
  public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) { 
    if (holder instanceof ItemViewHolder) { 
      ((ItemViewHolder) holder).item_tv.setText(mTitles.get(position)); 
      holder.itemView.setTag(position); 
    } else if (holder instanceof FootViewHolder) { 
      FootViewHolder footViewHolder = (FootViewHolder) holder; 
      switch (load_more_status) { 
      case SATUS_PULLUP_LOAD_MORE: 
        footViewHolder.foot_view_item_tv.setText("上拉加载更多..."); 
        break; 
      case SATUS_LOADING_MORE: 
        footViewHolder.foot_view_item_tv.setText("正在加载更多数据..."); 
        break; 
      case SATUS_UP_LOADING_MORE: 
        footViewHolder.foot_view_item_tv.setText("松开加载更多数据..."); 
        break; 
      } 
    } else if (holder instanceof FootEmptyHolder) { 
      FootEmptyHolder footViewHolder = (FootEmptyHolder) holder; 
      footViewHolder.empty.setLayoutParams(new ViewGroup.LayoutParams( 
          111, eview_height)); 
    } 
  } 
  /** 
   * 进行判断是普通Item视图还是FootView视图 
   * 
   * @param position 
   * @return 
   */ 
  @Override 
  public int getItemViewType(int position) { 
    // 最后一个item设置为footerView 
    if (position + 1 == getItemCount()) { 
      return TYPE_FOOTER_EMPTY; 
    } else if (position + 2 == getItemCount()) { 
      return TYPE_FOOTER; 
    } else { 
      return TYPE_ITEM; 
    } 
  } 
 //如果是页数的倍数 itemcount+2 
  @Override 
  public int getItemCount() { 
    if (mTitles.size() % pagesize != 0) { 
      return mTitles.size(); 
    } else { 
      return mTitles.size() + 2; 
    } 
    // return mTitles.size()+1; 
  } 
  // 自定义的ViewHolder，持有每个Item的的所有界面元素 
  public static class ItemViewHolder extends RecyclerView.ViewHolder { 
    public TextView item_tv; 
    public ItemViewHolder(View view) { 
      super(view); 
      item_tv = (TextView) view.findViewById(R.id.item_tv); 
    } 
  } 
  /** 
   * 底部FootView布局 
   */ 
  public static class FootViewHolder extends RecyclerView.ViewHolder { 
    private TextView foot_view_item_tv; 
    public FootViewHolder(View view) { 
      super(view); 
      foot_view_item_tv = (TextView) view 
          .findViewById(R.id.foot_view_item_tv); 
    } 
  } 
 //空白项 
  public static class FootEmptyHolder extends RecyclerView.ViewHolder { 
    private View empty; 
    public FootEmptyHolder(View view) { 
      super(view); 
      empty = view.findViewById(R.id.empty); 
    } 
  } 
  // 添加数据 
  public void addItem(List newDatas) { 
    // mTitles.add(position, data); 
    // notifyItemInserted(position); 
    newDatas.addAll(mTitles); 
    mTitles.removeAll(mTitles); 
    mTitles.addAll(newDatas); 
    notifyDataSetChanged(); 
  } 
 //更新添加数据 
  public void addMoreItem(List newDatas) { 
    mTitles.addAll(newDatas); 
    notifyDataSetChanged(); 
  } 
 //更新空白项高度 
  private void notifyEmptyView(int height) { 
    this.eview_height = height; 
    notifyItemChanged(getItemCount() - 1); 
  } 
 //空白回弹 伪回弹动画 
  private void resetEmptyView() { 
    final int dx = eview_height; 
    new Thread(new Runnable() { 
      @Override 
      public void run() { 
        // TODO Auto-generated method stub 
        final int time = 500; 
        final long startTime = new Date().getTime(); 
        TimeFlag = startTime; 
        long nowTime = new Date().getTime(); 
        while (startTime + time > nowTime && TimeFlag == startTime) { 
          nowTime = new Date().getTime(); 
          final int dt = (int) (nowTime - startTime); 
          parent.post(new Runnable() { 
            @Override 
            public void run() { 
              // TODO Auto-generated method stub 
              eview_height = eview_height * (time - dt) / time; 
              notifyDataSetChanged(); 
            } 
          }); 
          try { 
            Thread.sleep(10); 
          } catch (InterruptedException e) { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
          } 
        } 
        parent.post(new Runnable() { 
          @Override 
          public void run() { 
            // TODO Auto-generated method stub 
            eview_height = 0; 
            notifyDataSetChanged(); 
          } 
        }); 
      } 
    }).start(); 
  } 
 //停止加载更多 重置loading状态和显示文本 
  public void stopLoadMore() { 
    notifyDataSetChanged(); 
    loading = false; 
    RefreshFootAdapter.this 
    .changeMoreStatus(RefreshFootAdapter.this.SATUS_PULLUP_LOAD_MORE); 
  } 
  //改变加载条状态 
  private void changeMoreStatus(int status) { 
    if (loading) { 
      return; 
    } 
    load_more_status = status; 
    notifyDataSetChanged(); 
  } 
}

图1为滑动过程

Android RecyclerView上拉加载更多功能回弹实现代码

图2为松开加载

Android RecyclerView上拉加载更多功能回弹实现代码

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