Scroll content to widget with key - by Simon Lightfoot - 13/11/2019

scroll_to_key.dart

// MIT License
//
// Copyright (c) 2021 Simon Lightfoot
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//

import 'package:flutter/material.dart';

// NOTE: context of widget inside scrollable but above the widgets with the keys
bool scrollToKey(BuildContext context, Key key) {
  Element? found;
  void visitElement(Element el) {
    if (el.widget.key == key) {
      found = el;
      return;
    }
    el.visitChildren(visitElement);
  }

  context.visitChildElements(visitElement);
  if (found == null) {
    return false;
  }
  final scrollable = Scrollable.of(context);
  final box = found?.findRenderObject() as RenderBox?;
  if(scrollable == null || box == null){
    return false;
  }
  final offset = box.localToGlobal(
    Offset.zero,
    ancestor: scrollable.context.findRenderObject(),
  );
  scrollable.position.animateTo(
    scrollable.position.pixels + offset.dy,
    duration: const Duration(milliseconds: 350),
    curve: Curves.easeOutExpo,
  );
  return true;
}