Android下拉刷新框架实现代码实例

public interface IPullToRefresh<T extends View> { 
  public void setPullRefreshEnabled(boolean pullRefreshEnabled); 
  public void setPullLoadEnabled(boolean pullLoadEnabled); 
  public void setScrollLoadEnabled(boolean scrollLoadEnabled); 
  public boolean isPullRefreshEnabled(); 
  public boolean isPullLoadEnabled(); 
  public boolean isScrollLoadEnabled(); 
  public void setOnRefreshListener(OnRefreshListener<T> refreshListener); 
  public void onPullDownRefreshComplete(); 
  public void onPullUpRefreshComplete(); 
  public T getRefreshableView(); 
  public LoadingLayout getHeaderLoadingLayout(); 
  public LoadingLayout getFooterLoadingLayout(); 
  public void setLastUpdatedLabel(CharSequence label); 
} 

/** 
 * 判断刷新的View是否滑动到顶部 
 * 
 * @return true表示已经滑动到顶部，否则false 
 */ 
protected abstract boolean isReadyForPullDown(); 
 
/** 
 * 判断刷新的View是否滑动到底 
 * 
 * @return true表示已经滑动到底部，否则false 
 */ 
protected abstract boolean isReadyForPullUp(); 

/** 
 * 创建可以刷新的View 
 * 
 * @param context context 
 * @param attrs 属性 
 * @return View 
 */ 
protected abstract T createRefreshableView(Context context, AttributeSet attrs); 

@Override 
  public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
     
    mPullListView = new PullToRefreshListView(this); 
    setContentView(mPullListView); 
     
    // 上拉加载不可用 
    mPullListView.setPullLoadEnabled(false); 
    // 滚动到底自动加载可用 
    mPullListView.setScrollLoadEnabled(true); 
     
    mCurIndex = mLoadDataCount; 
    mListItems = new LinkedList<String>(); 
    mListItems.addAll(Arrays.asList(mStrings).subList(0, mCurIndex)); 
    mAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mListItems); 
     
    // 得到实际的ListView 
    mListView = mPullListView.getRefreshableView(); 
    // 绑定数据 
    mListView.setAdapter(mAdapter);     
    // 设置下拉刷新的listener 
    mPullListView.setOnRefreshListener(new OnRefreshListener<ListView>() { 
      @Override 
      public void onPullDownToRefresh(PullToRefreshBase<ListView> refreshView) { 
        mIsStart = true; 
        new GetDataTask().execute(); 
      } 
 
      @Override 
      public void onPullUpToRefresh(PullToRefreshBase<ListView> refreshView) { 
        mIsStart = false; 
        new GetDataTask().execute(); 
      } 
    }); 
    setLastUpdateTime(); 
     
    // 自动刷新 
    mPullListView.doPullRefreshing(true, 500); 
  } 

PullToRefreshListView#setScrollLoadEnabled方法，修正后的代码如下：
@Override 
public void setScrollLoadEnabled(boolean scrollLoadEnabled) { 
  if (isScrollLoadEnabled() == scrollLoadEnabled) { 
    return; 
  } 
   
  super.setScrollLoadEnabled(scrollLoadEnabled); 
   
  if (scrollLoadEnabled) { 
    // 设置Footer 
    if (null == mLoadMoreFooterLayout) { 
      mLoadMoreFooterLayout = new FooterLoadingLayout(getContext()); 
      mListView.addFooterView(mLoadMoreFooterLayout, null, false); 
    } 
     
    mLoadMoreFooterLayout.show(true); 
  } else { 
    if (null != mLoadMoreFooterLayout) { 
      mLoadMoreFooterLayout.show(false); 
    } 
  } 
} 

/** 
 * 显示或隐藏这个布局 
 * 
 * @param show flag 
 */ 
public void show(boolean show) { 
  // If is showing, do nothing. 
  if (show == (View.VISIBLE == getVisibility())) { 
    return; 
  } 
   
  ViewGroup.LayoutParams params = mContainer.getLayoutParams(); 
  if (null != params) { 
    if (show) { 
      params.height = ViewGroup.LayoutParams.WRAP_CONTENT; 
    } else { 
      params.height = 0; 
    } 
     
    requestLayout(); 
    setVisibility(show ? View.VISIBLE : View.INVISIBLE); 
  } 
} 

  @Override 
public void onPull(float scale) { 
  if (null == mRotationHelper) { 
    mRotationHelper = new ImageViewRotationHelper(mArrowImageView); 
  } 
   
  float angle = scale * 180f; // SUPPRESS CHECKSTYLE 
  mRotationHelper.setRotation(angle); 
} 

/** 
   * The image view rotation helper 
   * 
   * @author lihong06 
   * @since 2014-5-2 
   */ 
  static class ImageViewRotationHelper { 
    /** The imageview */ 
    private final ImageView mImageView; 
    /** The matrix */ 
    private Matrix mMatrix; 
    /** Pivot X */ 
    private float mRotationPivotX; 
    /** Pivot Y */ 
    private float mRotationPivotY; 
     
    /** 
     * The constructor method. 
     * 
     * @param imageView the image view 
     */ 
    public ImageViewRotationHelper(ImageView imageView) { 
      mImageView = imageView; 
    } 
     
    /** 
     * Sets the degrees that the view is rotated around the pivot point. Increasing values 
     * result in clockwise rotation. 
     * 
     * @param rotation The degrees of rotation. 
     * 
     * @see #getRotation() 
     * @see #getPivotX() 
     * @see #getPivotY() 
     * @see #setRotationX(float) 
     * @see #setRotationY(float) 
     * 
     * @attr ref android.R.styleable#View_rotation 
     */ 
    public void setRotation(float rotation) { 
      if (APIUtils.hasHoneycomb()) { 
        mImageView.setRotation(rotation); 
      } else { 
        if (null == mMatrix) { 
          mMatrix = new Matrix(); 
           
          // 计算旋转的中心点 
          Drawable imageDrawable = mImageView.getDrawable(); 
          if (null != imageDrawable) { 
            mRotationPivotX = Math.round(imageDrawable.getIntrinsicWidth() / 2f); 
            mRotationPivotY = Math.round(imageDrawable.getIntrinsicHeight() / 2f); 
          } 
        } 
         
        mMatrix.setRotate(rotation, mRotationPivotX, mRotationPivotY); 
        mImageView.setImageMatrix(mMatrix); 
      } 
    } 
  }