Android RecyclerView上拉加載更多功能回彈實現(xiàn)代碼

更新時間：2017年02月13日 16:01:44 作者：墜落糖梨

這篇文章主要介紹了Android RecyclerView上拉加載更多功能回彈實現(xiàn)代碼,非常不錯，具有參考借鑒價值，需要的朋友可以參考下

實現(xiàn)原理是使用RecyclerView的OnTouchListener方法監(jiān)聽滑動在adapter里面增加兩項footview 其中date.size為顯示的加載條，可以自定義，date.size+1為空白的View，我們設(shè)置其高度為0 我們通過LinearLayoutManager的 findLastVisibleItemPosition判斷顯示的最后一條數(shù)據(jù)，如果是空白view，表示加載條已經(jīng)完全展示，松開即可刷新。

回彈效果是通過在滑動時動態(tài)改變空白view的高度，達到阻尼效果，回彈時再動態(tài)將其改為0，達到回彈效果，通過loading防止加載過程中滑動導致顯示問題這里的回調(diào)采用了Runnable傳參

public class RefreshFootAdapter extends 
    RecyclerView.Adapter<RecyclerView.ViewHolder> { 
  // 上拉加載更多 
  public static final int SATUS_PULLUP_LOAD_MORE = 0; 
  // 正在加載中 
  public static final int SATUS_LOADING_MORE = 1; 
  public static final int SATUS_UP_LOADING_MORE = 2; 
  // 上拉加載更多狀態(tài)-默認為0 
  private int load_more_status = 0; 
  private LayoutInflater mInflater; 
  private List<String> 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;// 回彈時間 
  private RecyclerView parent; 
  private boolean loadmare;// 判斷當前是可加載更多 
  private boolean loading;// 判斷是否正在加載 
  private int startY, nowY;// 滑動判斷 
<span style="white-space:pre"> </span>//構(gòu)造函數(shù) 處理滑動監(jiān)聽 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<String>(); 
    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); 
            // 普通的滑動 
            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顯示類型 
   * 
   * @param parent 
   * @param viewType 
   * @return 
   */ 
  public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, 
      int viewType) { 
    // 進行判斷顯示類型，來創(chuàng)建返回不同的View 
    if (viewType == TYPE_ITEM) { 
      View view = mInflater.inflate(R.layout.item_recycler_layout, 
          parent, false); 
      // 這邊可以做一些屬性設(shè)置，甚至事件監(jiān)聽綁定 
      // 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); 
      // 這邊可以做一些屬性設(shè)置，甚至事件監(jiān)聽綁定 
      // 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); 
      // 這邊可以做一些屬性設(shè)置，甚至事件監(jiān)聽綁定 
      // view.setBackgroundColor(Color.RED); 
      FootEmptyHolder footEmptyViewHolder = new FootEmptyHolder( 
          foot_view_empty); 
      return footEmptyViewHolder; 
    } 
    return null; 
  } 
  /** 
   * 數(shù)據(jù)的綁定顯示 
   * 
   * @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("上拉加載更多..."); 
        break; 
      case SATUS_LOADING_MORE: 
        footViewHolder.foot_view_item_tv.setText("正在加載更多數(shù)據(jù)..."); 
        break; 
      case SATUS_UP_LOADING_MORE: 
        footViewHolder.foot_view_item_tv.setText("松開加載更多數(shù)據(jù)..."); 
        break; 
      } 
    } else if (holder instanceof FootEmptyHolder) { 
      FootEmptyHolder footViewHolder = (FootEmptyHolder) holder; 
      footViewHolder.empty.setLayoutParams(new ViewGroup.LayoutParams( 
          111, eview_height)); 
    } 
  } 
  /** 
   * 進行判斷是普通Item視圖還是FootView視圖 
   * 
   * @param position 
   * @return 
   */ 
  @Override 
  public int getItemViewType(int position) { 
    // 最后一個item設(shè)置為footerView 
    if (position + 1 == getItemCount()) { 
      return TYPE_FOOTER_EMPTY; 
    } else if (position + 2 == getItemCount()) { 
      return TYPE_FOOTER; 
    } else { 
      return TYPE_ITEM; 
    } 
  } 
<span style="white-space:pre"> </span>//如果是頁數(shù)的倍數(shù) itemcount+2 
  @Override 
  public int getItemCount() { 
    if (mTitles.size() % pagesize != 0) { 
      return mTitles.size(); 
    } else { 
      return mTitles.size() + 2; 
    } 
    // return mTitles.size()+1; 
  } 
  // 自定義的ViewHolder，持有每個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); 
    } 
  } 
<span style="white-space:pre"> </span>//空白項 
  public static class FootEmptyHolder extends RecyclerView.ViewHolder { 
    private View empty; 
    public FootEmptyHolder(View view) { 
      super(view); 
      empty = view.findViewById(R.id.empty); 
    } 
  } 
  // 添加數(shù)據(jù) 
  public void addItem(List<String> newDatas) { 
    // mTitles.add(position, data); 
    // notifyItemInserted(position); 
    newDatas.addAll(mTitles); 
    mTitles.removeAll(mTitles); 
    mTitles.addAll(newDatas); 
    notifyDataSetChanged(); 
  } 
<span style="white-space:pre"> </span>//更新添加數(shù)據(jù) 
  public void addMoreItem(List<String> newDatas) { 
    mTitles.addAll(newDatas); 
    notifyDataSetChanged(); 
  } 
<span style="white-space:pre"> </span>//更新空白項高度 
  private void notifyEmptyView(int height) { 
    this.eview_height = height; 
    notifyItemChanged(getItemCount() - 1); 
  } 
<span style="white-space:pre"> </span>//空白回彈 偽回彈動畫 
  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(); 
  } 
<span style="white-space:pre"> </span>//停止加載更多 重置loading狀態(tài)和顯示文本 
  public void stopLoadMore() { 
    notifyDataSetChanged(); 
    loading = false; 
    RefreshFootAdapter.this 
    .changeMoreStatus(RefreshFootAdapter.this.SATUS_PULLUP_LOAD_MORE); 
  } 
  //改變加載條狀態(tài) 
  private void changeMoreStatus(int status) { 
    if (loading) { 
      return; 
    } 
    load_more_status = status; 
    notifyDataSetChanged(); 
  } 
}

圖1為滑動過程