工具类，计算listview高度，gridview高度

public class Utility {

    public static  void setListViewHeightBasedOnChildren(ListView listView) {
               // 获取ListView对应的Adapter
                ListAdapter listAdapter = listView.getAdapter();
              if (listAdapter == null) {
                      return;
                 }
             int totalHeight = 0;
             // listAdapter.getCount()返回数据项的数目
             for (int i = 0; i < listAdapter.getCount(); i++) {
                    View listItem = listAdapter.getView(i, null, listView);
                  // 计算子项View 的宽高
                   listItem.measure(0, 0);
                     // 统计所有子项的总高度
                     totalHeight += listItem.getMeasuredHeight();
                   }
              ViewGroup.LayoutParams params = listView.getLayoutParams();
             params.height = totalHeight + (listView.getDividerHeight() * (listAdapter.getCount() - 1));
             // listView.getDividerHeight()获取子项间分隔符占用的高度
                // params.height最后得到整个ListView完整显示需要的高度
               listView.setLayoutParams(params);
           }

    public static int getheight(ListView listView) {
        ListAdapter listAdapter = listView.getAdapter();
        int totalHeight = 0;
        for (int i = 0; i < listAdapter.getCount(); i++) {
            View listItem = listAdapter.getView(i, null, listView);
            listItem.measure(0, 0);
            totalHeight += listItem.getMeasuredHeight();
        }
        return totalHeight;
    }
    public static void setGridViewHeightBasedOnChildren(GridView gridView) {
        // 获取GridView对应的Adapter
        ListAdapter listAdapter = gridView.getAdapter();
        if (listAdapter == null) {
            return;
        }
        int rows;
        int columns=0;
        int horizontalBorderHeight=0;
        Class<?> clazz=gridView.getClass();
        try {
            //利用反射，取得每行显示的个数
            Field column=clazz.getDeclaredField("mRequestedNumColumns");
            column.setAccessible(true);
            columns=(Integer)column.get(gridView);
            //利用反射，取得横向分割线高度
            Field horizontalSpacing=clazz.getDeclaredField("mRequestedHorizontalSpacing");
            horizontalSpacing.setAccessible(true);
            horizontalBorderHeight=(Integer)horizontalSpacing.get(gridView);
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        }
        //判断数据总数除以每行个数是否整除。不能整除代表有多余，需要加一行
        if(listAdapter.getCount()%columns>0){
            rows=listAdapter.getCount()/columns+1;
        }else {
            rows=listAdapter.getCount()/columns;
        }
        int totalHeight = 0;
        for (int i = 0; i < rows; i++) { //只计算每项高度*行数
            View listItem = listAdapter.getView(i, null, gridView);
            listItem.measure(0, 0); // 计算子项View 的宽高
            totalHeight += listItem.getMeasuredHeight(); // 统计所有子项的总高度
        }
        ViewGroup.LayoutParams params = gridView.getLayoutParams();
        params.height = totalHeight+horizontalBorderHeight*(rows-1);//最后加上分割线总高度
        gridView.setLayoutParams(params);
    }
}