@Override
  public boolean onItemLongClick(AdapterView<?> adapterView, View view, int i, long l)
  {
    // 至少有两个item的时候，才有排序
    if (getChildCount() >= 2)
    {
      mView = view;
      // 在调用getDrawingCache必须先调用
      view.setDrawingCacheEnabled(true);
      // 获取截图并设置
      Bitmap bitmap = view.getDrawingCache();
      mDragItemView.setImageBitmap(bitmap);
      // 设置拖拽的imageview的params
      mDragItemLayoutParams.gravity = Gravity.TOP | Gravity.LEFT;
      mDragItemLayoutParams.width = bitmap.getWidth();
      mDragItemLayoutParams.height = bitmap.getHeight();
      mDragItemLayoutParams.x = (mDownX - mDragItemLayoutParams.width / 2);
      mDragItemLayoutParams.y = (mDownY - mDragItemLayoutParams.height / 2);
      // 设置拖拽imageview的中心位于长按点击点
      mDragItemLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE //不接受按键事件
          | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE // 不接收触摸事件
          | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON  // 保持常亮
          | WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN; // place the window within the entire screen, ignoring decorations around the border (such as the status bar)
      mDragItemLayoutParams.format = PixelFormat.TRANSLUCENT;
      mDragItemLayoutParams.windowAnimations = 0;
      // 往WindowManager中添加拖拽的View
      mWindowManager.addView(mDragItemView, mDragItemLayoutParams);
      ((GridViewSortAdapter) getAdapter()).init();
      ((GridViewSortAdapter) getAdapter()).hideView(i);
      Log.d(TAG, "long click = " + i);
      mDragStarted = true;
    }
    return true;
  }
@Override
public boolean onTouchEvent(MotionEvent ev)
{
  switch (ev.getAction() & ev.getActionMasked())
  {
    case MotionEvent.ACTION_DOWN:
      mDownX = (int) ev.getRawX();
      mDownY = (int) ev.getRawY();
      break;
    case MotionEvent.ACTION_MOVE:
      if (mDragStarted)
      {
        // 保持中心
        mDragItemLayoutParams.x = (int) (ev.getRawX() - mDragItemView.getWidth() / 2);
        mDragItemLayoutParams.y = (int) (ev.getRawY() - mDragItemView.getHeight() / 2);
        // 更新params
        mWindowManager.updateViewLayout(mDragItemView, mDragItemLayoutParams);
        // ......
      }
      break;
    case MotionEvent.ACTION_UP:
      // ......
      break;
  }
  return super.onTouchEvent(ev);
}

@Override
public boolean onItemLongClick(AdapterView<?> adapterView, View view, int i, long l)
{
  // ......
  ((GridViewSortAdapter) getAdapter()).hideView(i);
  // ......
}
GridViewSortAdapter
public void hideView(int item)
{
  // ......
  mStartHideItemPosition = item;
  notifyDataSetChanged();
}
private int mStartHideItemPosition = AdapterView.INVALID_POSITION;
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
  ViewHolder holder = null;
  if (convertView == null)
  {
    convertView = LayoutInflater.from(mContext).inflate(R.layout.view_item_grid_view_sort, null);
    holder = new ViewHolder();
    holder.title = (TextView) convertView.findViewById(R.id.view_item_grid_view_sort_title);
    convertView.setTag(holder);
  }
  else
  {
    holder = (ViewHolder) convertView.getTag();
  }
  holder.title.setText(mTypeTitle.get(position));
  if (mStartHideItemPosition == position)
  {
    convertView.setVisibility(View.INVISIBLE);
  }
  else
  {
    convertView.setVisibility(View.VISIBLE);
  }
  return convertView;
}

@Override
 public boolean onTouchEvent(MotionEvent ev)
 {
  case MotionEvent.ACTION_MOVE:
  if (mDragStarted)
  {
    // ......
    int position = pointToPosition((int) ev.getX(), (int) ev.getY());
    // ......
  }
  break;
}

View view = mGridView.getChildAt(0);
mTranslateX = view.getWidth() + mHorizontalSpace;
mTranslateY = view.getHeight() + mVerticalSpace;

if (position != AdapterView.INVALID_POSITION && !((GridViewSortAdapter) getAdapter()).isInAnimation())
{  
   Log.d(TAG, "position = " + position);  
   ((GridViewSortAdapter) getAdapter()).swap(position);
}
GridSortAdapter
public void swap(int position)
{
  mAnimatorSetList.clear();
  int r_p = mPositionList.indexOf(position);
  Log.d(TAG, "r_p = " + r_p);
  if (mCurrentHideItemPosition < r_p)
  {
    for (int i = mCurrentHideItemPosition + 1; i <= r_p; i++)
    {
      View v = mGridView.getChildAt(mPositionList.get(i));
      if (i % mColsNum == 0 && i > 0)
      {
        startMoveAnimation(v, v.getTranslationX() + mTranslateX * (mColsNum - 1), v.getTranslationY() -
            mTranslateY);
      }
      else
      {
        startMoveAnimation(v, v.getTranslationX() - mTranslateX, 0);
      }
    }
  }
  else if (mCurrentHideItemPosition > r_p)
  {
    for (int i = r_p; i < mCurrentHideItemPosition; i++)
    {
      View v = mGridView.getChildAt(mPositionList.get(i));
      if ((i + 1) % mColsNum == 0)
      {
        startMoveAnimation(v, v.getTranslationX() - mTranslateX * (mColsNum - 1), v.getTranslationY() + mTranslateY);
      }
      else
      {
        startMoveAnimation(v, v.getTranslationX() + mTranslateX, 0);
      }
    }
  }
  resetPositionList();
  int value = mPositionList.get(mStartHideItemPosition);
  if (mStartHideItemPosition < r_p)
  {
    mPositionList.add(r_p + 1, value);
    mPositionList.remove(mStartHideItemPosition);
  }
  else if (mStartHideItemPosition > r_p)
  {
    mPositionList.add(r_p, value);
    mPositionList.remove(mStartHideItemPosition + 1);
  }
  mCurrentHideItemPosition = r_p;
}
public boolean isInAnimation()
{
  return mInAnimation;
}
private void resetPositionList()
{
  mPositionList.clear();
  for (int i = 0; i < mGridView.getChildCount(); i++)
  {
    mPositionList.add(i);
  }
}
private void startMoveAnimation(View myView, float x, float y)
{
  AnimatorSet set = new AnimatorSet();
  set.playTogether(
      ObjectAnimator.ofFloat(myView, "translationX", myView.getTranslationX(), x),
      ObjectAnimator.ofFloat(myView, "translationY", myView.getTranslationY(), y)
  );
  set.addListener(new Animator.AnimatorListener()
  {
    @Override
    public void onAnimationStart(Animator animator)
    {
      mInAnimation = true;
    }
    @Override
    public void onAnimationEnd(Animator animator)
    {
      mInAnimation = false;
    }
    @Override
    public void onAnimationCancel(Animator animator)
    {
    }
    @Override
    public void onAnimationRepeat(Animator animator)
    {
    }
  });
  mAnimatorSetList.add(set);
  set.setDuration(150).start();
}

mPositionList.indexOf(pointToPosition(x,y))