嵌套fragment时必须要重写 onDetach()

/**
     * 嵌套fragment时必须要重写 onDetach()如下
     */

    @Override

    public void onDetach()

    {

        super.onDetach();

        try

        {

            Field childFragmentManager = Fragment.class.getDeclaredField("mChildFragmentManager");

            childFragmentManager.setAccessible(true);

            childFragmentManager.set(this, null);

        } catch (NoSuchFieldException e)

        {

            throw new RuntimeException(e);

        } catch (IllegalAccessException e)

        {

            throw new RuntimeException(e);

        }

    }