private int sign = -1;  result_list.setOnGroupClickListener(new ExpandableListView.OnGroupClickListener() {            @Override            public boolean onGroupClick(ExpandableListView parent, final View v, int groupPosition, long id) {                final View view = result_list.getChildAt(0);                final int p = groupPosition;                if(sign == -1){                    result_list.expandGroup(groupPosition);                    scroll(result_list, p, view);                    sign = groupPosition;                }else if(sign == groupPosition){                    result_list.collapseGroup(sign);                    sign = -1;                }else{                    result_list.collapseGroup(sign);                    result_list.expandGroup(groupPosition);                    scroll(result_list, p, view);                    sign = groupPosition;                }                return true;            }        });  //控制滑动    public static void scroll(final ExpandableListView result_list,final int position,final View view){        new Handler().post(new Runnable() {            @Override            public void run() {                if (android.os.Build.VERSION.SDK_INT >= 11) {                    result_list.smoothScrollToPositionFromTop((position - 1),                            -view.getHeight(), 300);                }            }        });    }