获取ListView滚动精确值

项目需求要根据滚动位置，对title实现渐隐渐现效果，因此想获取ListView滚动时的精确位置。在网上找了很多都不能达到要求，千篇一律只有获取ListView滚动到某个item的高度整个的高度，例如:item高度为30，获得值只有0,30,60,90…在找寻中发现了ScrollView重写onScrollChanged可实现需求，于是在ListView中仿照重写onScrollChanged却没有作用。最后终于找到一种方法实现，特此分享给大家。

本文参考文：http://www.2cto.com/kf/201507/416142.html

布局文件就略写了，只有个ListView，直接上核心代码：

    //初始化控件
    mlistview = (ListView) findViewById(R.id.mylistview);
    String[] datas=new String[]{"11111","222222","333333","11111","222222","333333","11111","222222","333333"
                ,"11111","222222","333333","11111","222222","333333","11111","222222","333333"
                ,"11111","222222","333333","11111","222222","333333","11111","222222","333333"
                ,"11111","222222","333333","11111","222222","333333","11111","222222","333333"
                ,"11111","222222","333333","11111","222222","333333","11111","222222","333333"};
        mlistview.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, datas));

        mlistview.setOnScrollListener(new AbsListView.OnScrollListener() {
            private SparseArray<ItemRecod> recordSp = new SparseArray(0);
            private int mCurrentfirstVisibleItem = 0;

            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {

            }

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
                mCurrentfirstVisibleItem = firstVisibleItem;
                View firstView = view.getChildAt(0);
                if (null != firstView) {
                    ItemRecod itemRecord = recordSp.get(firstVisibleItem);
                    if (null == itemRecord) {
                        itemRecord = new ItemRecod();
                    }
                    //item高度
                    itemRecord.height = firstView.getHeight();
                    //滑动位置距顶部距离(负值)
                    itemRecord.top = firstView.getTop();
                    recordSp.append(firstVisibleItem, itemRecord);
                }
                Log.d("onScroll", getScrollY() + "");
            }

            //获取滚动精确值
            private int getScrollY() {
                int height = 0;
                for (int i = 0; i < mCurrentfirstVisibleItem; i++) {
                    ItemRecod itemRecod = recordSp.get(i);
                    height += itemRecod.height;
                }
                ItemRecod itemRecod = recordSp.get(mCurrentfirstVisibleItem);
                if (null == itemRecod) {
                    itemRecod = new ItemRecod();
                }
                return height - itemRecod.top;
            }

            class ItemRecod {
                int height = 0;
                int top = 0;
            }
        });

这样 getScrollY()就可以获取ListView滚动的精确位置了，希望此文也能帮到有同样需求的人。