Android NestedScrollView刚开始加载完界面

直接上代码：
1 刚开始加载完界面，判断内容是否全部展示，.viewTreeObserver.addOnGlobalLayoutListener是为了保证控件view加载完成

nestedscrollview.viewTreeObserver.addOnGlobalLayoutListener {

            if(!canScroll()){
                mNext?.alpha = 1f
                mNext?.isEnabled = true
            }
        }



    /**
     * 判断是否可以滚动 如果不可以滚动 返回false说明界面已经全部加载显示出来了；true则表示需要滑动 才显示全
     */
    fun canScroll(): Boolean {
//        val sv: ScrollView = findViewById(android.R.id.dtv_source_info_more_sv) as ScrollView
        val child: View = nestedscrollview.getChildAt(0)
        if (child != null) {
            val childHeight = child.measuredHeight
            return nestedscrollview.getHeight() < childHeight
        }
        return false
    }

2 判断是否滑动到底部，来处理底部按钮是否可点击的状态

        nestedscrollview?.setOnScrollChangeListener { v, scrollX, scrollY, oldScrollX, oldScrollY ->
            Log.d("nestedscro scrollY->", scrollY?.toString())
            Log.d("nestedscro oldScrollY->", oldScrollY?.toString())

// 判断顶部标题栏显示还是隐藏
            if (scrollY >= 100) {
                rl_focus_on_tanka_no_title?.visibility = View.GONE
                rl_focus_on_tanka_title?.visibility = View.VISIBLE
                view_space_top?.visibility = View.VISIBLE
            } else {
                rl_focus_on_tanka_no_title?.visibility = View.VISIBLE
                rl_focus_on_tanka_title?.visibility = View.GONE
                view_space_top?.visibility = View.GONE
            }

            // 滚动到底
            if (scrollY == ((v as NestedScrollView).getChildAt(0).getMeasuredHeight() - v.getMeasuredHeight())) {

                mNext?.alpha = 1f
                mNext?.isEnabled = true
            }

        }