android开发教程之实现listview下拉刷新和上拉刷新效果

 private static final String TAG = PullToLoadListView.class.getSimpleName();

 private static final int STATE_NON = 0;
 private static final int STATE_PULL_TO_REFRESH = 1;
 private static final int STATE_RELEASE_TO_REFRESH = 2;
 private static final int STATE_REFRESHING = 3;

 private int state;

 private int firstVisibleItem;
 private int lastVisisibleItem;

 private float prevY = 0;

 private View headerView;
 private View footerView;

 // header widgets
 private ProgressBar headerProgressBar;
 private ImageView headerImageArrow;
 private TextView headerText;
 private RotateAnimation headerArrowAnim;
 private RotateAnimation headerArrowReverseAnim;
 // footer widgets
 private ProgressBar footerProgressBar;
 private TextView footerText;

 private boolean headerIsHanding = false;
 private boolean footerIsHanding = false;

 private int headerHeight;
 private int footerHeight;

 private ResetAnimation resetAnim;

 private OnLoadingListener onLoadingListener;

 private OnScrollListener onScrollListener;

 public PullToLoadListView(Context context) {
  super(context);
  init(context);
 }

 public PullToLoadListView(Context context, AttributeSet attrs) {
  super(context, attrs);
  init(context);
 }

 private void init(Context context) {
  state = STATE_NON;
  firstVisibleItem = 0;
  lastVisisibleItem = 0;

  LayoutInflater inflater = LayoutInflater.from(context);
  headerView = inflater.inflate(R.layout.view_pull_header, null);
  footerView = inflater.inflate(R.layout.view_pull_footer, null);

  headerProgressBar = (ProgressBar) headerView.findViewById(R.id.progressbar);
  headerImageArrow = (ImageView) headerView.findViewById(R.id.arrow);
  headerText = (TextView) headerView.findViewById(R.id.text);
  headerArrowAnim = new RotateAnimation(0, -180, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
  headerArrowAnim.setDuration(300);
  headerArrowAnim.setFillAfter(true);
  headerArrowReverseAnim = new RotateAnimation(-180, 0, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
  headerArrowReverseAnim.setDuration(300);
  headerArrowReverseAnim.setFillAfter(true);

  footerProgressBar = (ProgressBar) footerView.findViewById(R.id.progressbar);
  footerText = (TextView) footerView.findViewById(R.id.text);

  measureView(headerView);
  measureView(footerView);
  headerHeight = headerView.getMeasuredHeight();
  footerHeight = footerView.getMeasuredHeight();
  headerView.setPadding(0, -1 * headerView.getMeasuredHeight(), 0, 0);
  footerView.setPadding(0, -1 * footerView.getMeasuredHeight(), 0, 0);
  headerView.invalidate();
  footerView.invalidate();
  addHeaderView(headerView, null, false);
  addFooterView(footerView, null, false);

  super.setOnScrollListener(this);
 }

 private void measureView(View view) {
  ViewGroup.LayoutParams lp = view.getLayoutParams();
  if(lp == null) {
   lp = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
  }
  int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0, lp.width);
  int childHeightSpec;
  if(lp.height > 0) {
   childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.EXACTLY);
  } else {
   childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
  }
  view.measure(childWidthSpec, childHeightSpec);
 }

 private void resetHeader() {
  //  headerView.setPadding(0, -1 * headerHeight, 0, 0);
  resetAnim = new ResetAnimation(headerView, headerHeight, headerView.getPaddingTop());
  resetAnim.start();
 }

 private void resetFooter() {
  resetAnim = new ResetAnimation(footerView, footerHeight, footerView.getPaddingTop());
  resetAnim.start();
 }

 private void changeHeaderViewByState(int state) {
  if(this.state == state) {
   return ;
  }
  int prevState = this.state;
  this.state = state;

  switch(state) {
  case STATE_NON:
   headerProgressBar.setVisibility(View.INVISIBLE);
   headerImageArrow.setVisibility(View.VISIBLE);
   headerImageArrow.clearAnimation();
   headerText.setText("Pull Down To Refresh");
   break;
  case STATE_PULL_TO_REFRESH:
   headerProgressBar.setVisibility(View.INVISIBLE);
   headerImageArrow.setVisibility(View.VISIBLE);
   headerText.setText("Pull Down To Refresh");
   if(prevState == STATE_RELEASE_TO_REFRESH) {
    headerImageArrow.startAnimation(headerArrowReverseAnim);
   } else {
    headerImageArrow.clearAnimation();
   }
   break;
  case STATE_RELEASE_TO_REFRESH:
   headerProgressBar.setVisibility(View.INVISIBLE);
   headerImageArrow.setVisibility(View.VISIBLE);
   headerImageArrow.startAnimation(headerArrowAnim);
   headerText.setText("Release To Refresh");
   break;
  case STATE_REFRESHING:
   headerProgressBar.setVisibility(View.VISIBLE);
   headerImageArrow.setVisibility(View.INVISIBLE);
   headerImageArrow.clearAnimation();
   headerText.setText("Refreshing");
   break;
  default:
   break;
  }
 }

 private void changeFooterViewByState(int state) {
  if(this.state == state) {
   return ;
  }
  this.state = state;

  switch(state) {
  case STATE_NON:
   footerProgressBar.setVisibility(View.INVISIBLE);
   footerText.setText("Pull Up To Refresh");
   break;
  case STATE_PULL_TO_REFRESH:
   footerProgressBar.setVisibility(View.INVISIBLE);
   footerText.setText("Pull Up To Refresh");
   break;
  case STATE_RELEASE_TO_REFRESH:
   footerProgressBar.setVisibility(View.INVISIBLE);
   footerText.setText("Release To Refresh");
   break;
  case STATE_REFRESHING:
   footerProgressBar.setVisibility(View.VISIBLE);
   footerText.setText("Refreshing");
   break;
  default:
   break;
  }
 }

 @Override
 public void setOnScrollListener(OnScrollListener l) {
  this.onScrollListener = l;
 }

 public void setOnLoadingListener(OnLoadingListener onLoadingListener) {
  this.onLoadingListener = onLoadingListener;
 }

 public void loadCompleted() {
  if(headerIsHanding) {
   changeHeaderViewByState(STATE_NON);
   resetHeader();
   headerIsHanding = false;
  }
  if(footerIsHanding) {
   changeFooterViewByState(STATE_NON);
   resetFooter();
   footerIsHanding = false;
  }
 }

 private void handleMoveHeaderEvent(MotionEvent ev) {
  headerIsHanding = true;
  float tempY = ev.getRawY();
  float vector = tempY - prevY;
  vector /= 2;
  prevY = tempY;
  if(vector > 0) {
   int newPadding = (int) (headerView.getPaddingTop() + vector);
   newPadding = Math.min(newPadding, headerHeight / 2);
   headerView.setPadding(0, newPadding, 0, 0);
   if(state != STATE_REFRESHING) {
    if(newPadding > 0) {
     changeHeaderViewByState(STATE_RELEASE_TO_REFRESH);
    } else {
     changeHeaderViewByState(STATE_PULL_TO_REFRESH);
    }
   }
  } else {
   if(state == STATE_RELEASE_TO_REFRESH || state == STATE_PULL_TO_REFRESH) {
    int newPadding = (int) (headerView.getPaddingTop() + vector);
    newPadding = Math.max(newPadding, -1 * headerHeight);
    headerView.setPadding(0, newPadding, 0, 0);
    if(newPadding <= -1 * headerHeight) {
     changeHeaderViewByState(STATE_NON);
     headerIsHanding = false;
    } else if(newPadding <= 0) {
     changeHeaderViewByState(STATE_PULL_TO_REFRESH);
    } else {

    }
   }
  }
 }

 private void handleMoveFooterEvent(MotionEvent ev) {
  footerIsHanding = true;
  float tempY = ev.getRawY();
  float vector = tempY - prevY;
  vector /= 2;
  prevY = tempY;
  if(vector < 0) {
   int newPadding = (int) (footerView.getPaddingTop() - vector);
   if(newPadding > 0) {
    newPadding = 0;
   }
   footerView.setPadding(0, newPadding, 0, 0);
   if(state != STATE_REFRESHING) {
    if(newPadding < 0) {
     changeFooterViewByState(STATE_PULL_TO_REFRESH);
    } else {
     changeFooterViewByState(STATE_RELEASE_TO_REFRESH);
    }
   }
  } else {
   int newPadding = (int) (footerView.getPaddingTop() - vector);
   newPadding = Math.min(newPadding, footerHeight);
   footerView.setPadding(0, newPadding, 0, 0);
   if(newPadding <= -1 * footerHeight) {
    changeFooterViewByState(STATE_NON);
    footerIsHanding = false;
   } else if(newPadding < 0) {
    changeFooterViewByState(STATE_PULL_TO_REFRESH);
   }
  }
 }

 @Override
 public boolean onTouchEvent(MotionEvent ev) {
  switch(ev.getAction()) {
  case MotionEvent.ACTION_DOWN:
   prevY = ev.getRawY();
   break;
  case MotionEvent.ACTION_UP:
   if(state == STATE_RELEASE_TO_REFRESH) {
    if(headerIsHanding) {
     changeHeaderViewByState(STATE_REFRESHING);
     if(onLoadingListener != null) {
      onLoadingListener.onLoadNew();
     }
    }
    if(footerIsHanding) {
     changeFooterViewByState(STATE_REFRESHING);
     if(onLoadingListener != null) {
      onLoadingListener.onLoadMore();
     }
    }
   } else if(state == STATE_PULL_TO_REFRESH) {
    if(headerIsHanding) {
     changeHeaderViewByState(STATE_NON);
     resetHeader();
     headerIsHanding = false;
    }
    if(footerIsHanding) {
     changeFooterViewByState(STATE_NON);
     resetFooter();
     footerIsHanding = false;
    }
   } else if(state == STATE_NON) {
    headerIsHanding = false;
    footerIsHanding = false;
   } else {
    // state == STATE_REFRESHING
    // ignore
   }
   break;
  case MotionEvent.ACTION_MOVE:
   if(resetAnim == null || !resetAnim.run) {

    if(state != STATE_REFRESHING) {
     Adapter adapter = getAdapter();
     if(adapter == null) {
      handleMoveHeaderEvent(ev);
     } else {
      final int count = adapter.getCount();
      if(count <= 0) {
       handleMoveHeaderEvent(ev);
      } else {
       float tempY = ev.getRawY();
       float vector = tempY - prevY;
       if(firstVisibleItem == 0 && lastVisisibleItem == count - 1) {
        if(headerIsHanding) {
         handleMoveHeaderEvent(ev);
        } else if(footerIsHanding) {
         handleMoveFooterEvent(ev);
        } else {
         if(vector > 0) {
          handleMoveHeaderEvent(ev);
         } else if(vector < 0) {
          handleMoveFooterEvent(ev);
         } else {
          // ignore vector == 0
         }
        }
       } else if(firstVisibleItem == 0 && vector > 0) {
        handleMoveHeaderEvent(ev);
       } else if(lastVisisibleItem == count - 1 && vector < 0) {
        handleMoveFooterEvent(ev);
       } else {
        // ignore
       }
      }
     }
    }
   }
   break;
  default:
   break;
  }
  return super.onTouchEvent(ev);
 }

 @Override
 public void onScrollStateChanged(AbsListView view, int scrollState) {
  if(onScrollListener != null) {
   onScrollListener.onScrollStateChanged(view, scrollState);
  }
 }

 @Override
 public void onScroll(AbsListView view, int firstVisibleItem,
   int visibleItemCount, int totalItemCount) {
  this.firstVisibleItem = firstVisibleItem;
  this.lastVisisibleItem = firstVisibleItem + visibleItemCount - 1;
  if(onScrollListener != null) {
   onScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount);
  }
 }

 static class ResetAnimation extends Thread {

  static final int DURATION = 600;

  static final int INTERVAL = 5;

  View view;
  int orignalHeight;
  int paddingTop;

  boolean run = false;

  ResetAnimation(View view, int orignalHeight, int paddingTop) {
   this.view = view;
   this.orignalHeight = orignalHeight;
   this.paddingTop = paddingTop;
  }

  public void run() {
   run = true;
   int total = orignalHeight * 2 + paddingTop;
   int timeTotal = DURATION / INTERVAL;
   int piece = total / timeTotal;
   int time = 0;
   final View view = this.view;
   final int paddingTop = this.paddingTop;
   do {
    final int nextPaddingTop = paddingTop - time * piece;
    view.post(new Runnable() {
     public void run() {
      view.setPadding(0, nextPaddingTop, 0, 0);
      view.postInvalidate();
     }
    });
    try {
     sleep(INTERVAL);
    } catch (InterruptedException e) {
     e.printStackTrace();
    }
    time ++;
   } while(time < timeTotal);
   run = false;
  }
 }

 public interface OnLoadingListener {

  public void onLoadNew();

  public void onLoadMore();
 }

}