如何在颤振中创建渐变条应用栏？

Question

我只想创建一个像这样的银色应用程序栏，但我被困住了。

到目前为止，我尝试的是创建一个 sliver 应用程序栏，并在具有一些渐变的灵活空间中使用容器，但与链接相比并不是那么好。

所以请帮助我更准确地实现它。

提前致谢，

Answer 1

检查这个

import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      title: _title,
      home: MyStatefulWidget(),
    );
  }
}

class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key? key}) : super(key: key);

  @override
  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}

class _MyStatefulWidgetState extends State<MyStatefulWidget> {
  bool _pinned = true;
  bool _snap = false;
  bool _floating = false;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CustomScrollView(
        slivers: <Widget>[
          SliverAppBar(
            pinned: _pinned,
            snap: _snap,
            floating: _floating,
            expandedHeight: 160.0,
            flexibleSpace: const FlexibleSpaceBar(
              title: Text('SliverAppBar'),
              background: FlutterLogo(),
            ),
          ),
          const SliverToBoxAdapter(
            child: SizedBox(
              height: 20,
              child: Center(
                child: Text('Scroll to see SliverAppBar'),
              ),
            ),
          ),
          SliverList(
            delegate: SliverChildBuilderDelegate(
                  (BuildContext context, int index) {
                return Container(
                  color: index.isOdd ? Colors.white : Colors.black12,
                  height: 100.0,
                  child: Center(
                    child: Text('$index', textScaleFactor: 5),
                  ),
                );
              },
              childCount: 20,
            ),
          ),
        ],
      ),
      bottomNavigationBar: BottomAppBar(
        child: Padding(
          padding: const EdgeInsets.all(8),
          child: OverflowBar(
            overflowAlignment: OverflowBarAlignment.center,
            children: <Widget>[
              Row(
                mainAxisSize: MainAxisSize.min,
                children: <Widget>[
                  const Text('pinned'),
                  Switch(
                    onChanged: (bool val) {
                      setState(() {
                        _pinned = val;
                      });
                    },
                    value: _pinned,
                  ),
                ],
              ),
              Row(
                mainAxisSize: MainAxisSize.min,
                children: <Widget>[
                  const Text('snap'),
                  Switch(
                    onChanged: (bool val) {
                      setState(() {
                        _snap = val;
                        _floating = _floating || _snap;
                      });
                    },
                    value: _snap,
                  ),
                ],
              ),
              Row(
                mainAxisSize: MainAxisSize.min,
                children: <Widget>[
                  const Text('floating'),
                  Switch(
                    onChanged: (bool val) {
                      setState(() {
                        _floating = val;
                        _snap = _snap && _floating;
                      });
                    },
                    value: _floating,
                  ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }
}