首先这是一个全体布局往上的需求

 rootLayout.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                Log.v("test", "布局变化");
                Rect rect = new Rect();
                rootLayout.getWindowVisibleDisplayFrame(rect);
                Log.v("test", rect.bottom+"  "+rect.top+"  "+rect.left+"      "+rect.right);

                int screenHeight = getWindow().getDecorView().getHeight();
                int naviBarHeight= SoftKeyboardFixerForFullscreen.getNavigationBarHeight(ReplyActivity.this);
                int softHeight = screenHeight - rect.bottom-naviBarHeight;
                Log.v("test", softHeight+"  "+screenHeight);
                Log.v("test","导航栏高度"+naviBarHeight);
                if (softHeight > 0) {
                    rootLayout.scrollTo(0,softHeight);
                } else {
                    rootLayout.scrollTo(0,0);
                }

            }
        });

   /**
     * 获取Bar高度
     *
     * @param context context
     * @param barName 名称
     * @return Bar高度
     */
    private static int getBarHeight(Context context, String barName) {
        // 获得状态栏高度
        int resourceId = context.getResources().getIdentifier(barName, "dimen", "android");
        return context.getResources().getDimensionPixelSize(resourceId);
    }
  /**
     * 是否有NavigationBar
     *
     * @param activity 上下文
     * @return 是否有NavigationBar
     */
    private static boolean hasNavBar(Activity activity) {
        WindowManager windowManager = activity.getWindowManager();
        Display d = windowManager.getDefaultDisplay();

        DisplayMetrics realDisplayMetrics = new DisplayMetrics();
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            d.getRealMetrics(realDisplayMetrics);
        }

        int realHeight = realDisplayMetrics.heightPixels;
        int realWidth = realDisplayMetrics.widthPixels;

        DisplayMetrics displayMetrics = new DisplayMetrics();
        d.getMetrics(displayMetrics);

        int displayHeight = displayMetrics.heightPixels;
        int displayWidth = displayMetrics.widthPixels;

        return (realWidth - displayWidth) > 0 || (realHeight - displayHeight) > 0;
    }
/**
     * 获取导航栏高度
     *
     * @param activity activity
     * @return 导航栏高度
     */
    public static int getNavigationBarHeight(Activity activity) {
        if (hasNavBar(activity)) {
            // 获得导航栏高度
            return getBarHeight(activity, NAV_BAR_HEIGHT_RES_NAME);
        } else {
            return 0;
        }
    }

下面两个方法来源
https://blog.csdn.net/qq_35605213/article/details/81005187