import 'dart:ui';

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

class MineHeaderDelegate extends SliverPersistentHeaderDelegate {
  double _height;

  MineHeaderDelegate() : super() {
    _height = MediaQueryData.fromWindow(window).padding.top + 44;
  }

  @override
  Widget build(
      BuildContext context, double shrinkOffset, bool overlapsContent) {
    print('${shrinkOffset.toString()}');
    double percent = shrinkOffset / _height;
    print('${percent.toString()}');
    return MineHeader(Colors.red.withOpacity(percent));
  }

  @override
  double get maxExtent => _height;

  @override
  double get minExtent => _height;

  @override
  bool shouldRebuild(SliverPersistentHeaderDelegate oldDelegate) =>
      false; // 如果内容需要更新，设置为true
}

class MineHeader extends StatelessWidget {
  final Color color;

  MineHeader(this.color);

  @override
  Widget build(BuildContext context) {
    return Container(
        color: color,
        child: Column(
          children: <Widget>[
            Expanded(child: Container()),
            Container(
              width: double.infinity,
              height: 44,
              child: Row(
                mainAxisAlignment: MainAxisAlignment.end,
                crossAxisAlignment: CrossAxisAlignment.center,
                children: <Widget>[
                  Icon(
                    Icons.settings,
                    color: Colors.white,
                  ),
                  Icon(
                    Icons.chat,
                    color: Colors.white,
                  )
                ],
              ),
            )
          ],
        ));
  }
}