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如何设置颤振时嵌套滚动视图中SliVerAppBar的最小高度

flutter dart user-interface

Dominik Roszkowski · 技术社区 · 7 年前

我想在一个普通的scaffold应用程序的nestedcollview中使用sliverappbar。当用户向下滚动时,我还希望有一些应用程序栏的最小高度。

我不知道如何使用PreferredSize小部件或任何其他在线解决方案,例如 this .

下面是我当前的简化解决方案:

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(primarySwatch: Colors.blue, fontFamily: 'Oswald'),
      home: SliverHome(),
    );
  }
}

class SliverHome extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: testHome(),
    );
  }

  Widget testHome() {
    return Scaffold(
      body: NestedScrollView(
        headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
          return <Widget>[
            SliverAppBar( // this is where I would like to set some minimum constraint
              expandedHeight: 300,
              floating: false,
              pinned: true,
              flexibleSpace: Container(
                padding: EdgeInsets.all(10),
                height: 340,
                width: double.infinity,
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.end,
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: <Widget>[
                    Container(
                      height: 40,
                    ),
                    Container(
                      height: 60,
                    ),
                    Expanded(child: Container()),
                    Text('TEST'),
                  ],
                ),
                decoration: BoxDecoration(
                    image: DecorationImage(
                        image: NetworkImage('https://picsum.photos/400/400'),
                        fit: BoxFit.cover)),
              ),
            )
          ];
        },
        body: Container(),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () => {},
        tooltip: '+',
        child: Icon(Icons.accessibility_new),
      ),
    );
  }
}

我想停止在接近60 dp的地方缩小应用程序栏

screenshot

2 回复 | 直到 7 年前

anmol.majhail 7 年前

这实际上是请求的功能- https://github.com/flutter/flutter/issues/21298

周围的工作就是利用 Bottom

SliverAppBar(
              // this is where I would like to set some minimum constraint
              expandedHeight: 300,
              floating: false,
              pinned: true,
              bottom: PreferredSize(                       // Add this code
                preferredSize: Size.fromHeight(60.0),      // Add this code
                child: Text(''),                           // Add this code
              ),                                           // Add this code
              flexibleSpace: Container(
                padding: EdgeInsets.all(10),
                height: 340,
                width: double.infinity,
                child: Column(
                  mainAxisAlignment: MainAxisAlignment.end,
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: <Widget>[
                    Container(
                      height: 40,
                    ),
                    Container(
                      height: 60,
                    ),
                    Expanded(child: Container()),
                    Text('TEST'),
                  ],
                ),
                decoration: BoxDecoration(
                    image: DecorationImage(
                        image: NetworkImage('https://picsum.photos/400/400'),
                        fit: BoxFit.cover)),
              ),
            )

Mir Mahfuz 7 年前

在从容器中减少大小后,代码也可以正常工作。

 SliverAppBar( // this is where I would like to set some minimum constraint
          expandedHeight: 300,
          floating: false,
          pinned: true,
          flexibleSpace: Container(
            padding: EdgeInsets.all(10),
            height: 340,
            width: double.infinity,
            child: Column(
              mainAxisAlignment: MainAxisAlignment.end,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: <Widget>[
                Container(
                  height: 10,  //decreas the size
                ),
                Container(
                  height: 10, //decrease the size
                ),
                Expanded(child: Container()),
                Text('TEST'),
              ],
            ),
            decoration: BoxDecoration(
                image: DecorationImage(
                    image: NetworkImage('https://picsum.photos/400/400'),
                    fit: BoxFit.cover)),
          ),
        )