Android初级教程_用ExpandableListView实现类似QQ好友列表

我们知道QQ好友列表分类使用ExpandableListView实现的,但是它在此基础上做改进,如打开分组,滑动时组标题会悬浮在最上端.

方便用户关闭分组.效果类似于下图:

实现代码如下所示:

@Override
    public void onScroll(AbsListView view, int firstVisibleItem,
            int visibleItemCount, int totalItemCount) {
        //防止三星,魅族等手机第一个条目可以一直往下拉,父条目和悬浮同时出现的问题
        if(firstVisibleItem==0){
            view_flotage.setVisibility(View.GONE);
        }
        // 控制滑动时TextView的显示与隐藏
        int npos = view.pointToPosition(0, 0);
        if (npos != AdapterView.INVALID_POSITION) {
            long pos = expandableList.getExpandableListPosition(npos);
            int childPos = ExpandableListView.getPackedPositionChild(pos);
            final int groupPos = ExpandableListView.getPackedPositionGroup(pos);
            if (childPos == AdapterView.INVALID_POSITION) {
                View groupView = expandableList.getChildAt(npos
                        - expandableList.getFirstVisiblePosition());
                indicatorGroupHeight = groupView.getHeight();
            }

            if (indicatorGroupHeight == 0) {
                return;
            }
            // if (isExpanded) {
            if (count_expand > 0) {
                the_group_expand_position = groupPos;
                group_content.setText(groupData.get(the_group_expand_position)
                        .get("group_text"));
                if (the_group_expand_position != groupPos||!expandableList.isGroupExpanded(groupPos)) {
                    view_flotage.setVisibility(View.GONE);
                } else {
                    view_flotage.setVisibility(View.VISIBLE);
                }
            }
            if (count_expand == 0) {
                view_flotage.setVisibility(View.GONE);
            }
        }

        if (the_group_expand_position == -1) {
            return;
        }
        /**
         * calculate point (0,indicatorGroupHeight)
         */
        int showHeight = getHeight();
        MarginLayoutParams layoutParams = (MarginLayoutParams) view_flotage
                .getLayoutParams();
        // 得到悬浮的条滑出屏幕多少
        layoutParams.topMargin = -(indicatorGroupHeight - showHeight);
        view_flotage.setLayoutParams(layoutParams);
    }

有的手机品牌不一样可能会出现如下情况:

所以需要加上如下代码:

//防止三星,魅族等手机第一个条目可以一直往下拉,父条目和悬浮同时出现的问题
        if(firstVisibleItem==0){
            view_flotage.setVisibility(View.GONE);
        }

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最近有些网友需要代码,现在附上下载地址.http://download.csdn.net/detail/johnny901114/4513242