超顺滑！优化android ListView拖拽移位

                                                                                                   

由于项目需求，要实现类似于ios上的listview的排序。之前在网络上搜索，发现了下面这篇文章，先感谢一下：

http://blog.csdn.net/jj120522/article/details/8240407#comments。

后来看到魅拍上面也有类似的功能，但是性能要快好几倍，同时动画也非常的流畅，于是试着自己优化下。现在性能上基本OK，还有些细节的地方需要优化下，代码也需要整

理下。等整理完了，把代码放上来供大家参考下。

源码地址：https://github.com/wanggang1984117/DragListView                                                                     

触摸事件处理：

/** * 触摸事件处理 */@Overridepublic boolean onTouchEvent(MotionEvent ev) {// item的view不为空，且获取的dragPosition有效if (dragImageView != null && dragPosition != INVALID_POSITION&& !isLock) {int action = ev.getAction();switch (action) {case MotionEvent.ACTION_UP:int upY = (int) ev.getY();stopDrag();onDrop(upY);break;case MotionEvent.ACTION_MOVE:int moveY = (int) ev.getY();onDrag(moveY);testAnimation(moveY);break;case MotionEvent.ACTION_DOWN:break;default:break;}return true;// 取消ListView滑动.}return super.onTouchEvent(ev);}

主要的动画部分：

private void testAnimation(int y){final DragListAdapter adapter = (DragListAdapter) getAdapter();int tempPosition = pointToPosition(0, y);if (tempPosition == INVALID_POSITION || tempPosition == lastPosition) {return;}mFirstVisiblePosition = getFirstVisiblePosition();dragPosition = tempPosition;onChangeCopy(lastPosition, dragPosition);int MoveNum = tempPosition - lastPosition;int count = Math.abs(MoveNum);for(int i=1; i<=count; i++){int xAbsOffset, yAbsOffset;//向下dragif(MoveNum > 0){if(lastFlag == -1){lastFlag = 0;isSameDragDirection = true;}if(lastFlag == 1){turnUpPosition = tempPosition;lastFlag = 0;isSameDragDirection = !isSameDragDirection;}if(isSameDragDirection){holdPosition = lastPosition + 1;}else{if(startPosition < tempPosition){holdPosition = lastPosition + 1;isSameDragDirection = !isSameDragDirection;}else{holdPosition = lastPosition;}}xAbsOffset = 0;yAbsOffset = - mItemVerticalSpacing;lastPosition++;}//向上dragelse{if(lastFlag == -1){lastFlag = 1;isSameDragDirection = true;}if(lastFlag == 0){turnDownPosition = tempPosition;lastFlag = 1;isSameDragDirection = !isSameDragDirection;}if(isSameDragDirection){holdPosition = lastPosition -1;}else{if(startPosition > tempPosition){holdPosition = lastPosition -1;isSameDragDirection = !isSameDragDirection;}else{holdPosition = lastPosition;}}xAbsOffset = 0;yAbsOffset = mItemVerticalSpacing;lastPosition--;}adapter.setHeight(mItemVerticalSpacing);adapter.setIsSameDragDirection(isSameDragDirection);adapter.setLastFlag(lastFlag);    ViewGroup moveView = (ViewGroup)getChildAt(holdPosition - getFirstVisiblePosition());        Animation animation;    if(isSameDragDirection){    animation = getFromSelfAnimation(xAbsOffset, yAbsOffset);    }else{    animation = getToSelfAnimation(xAbsOffset, -yAbsOffset);    }    moveView.startAnimation(animation);}}

动画部分的变量说明下次补充。