颤振选择对话框 - 将过滤器字段滚动到视图中

Posted 2023-02-23

【中文标题】颤振选择对话框 - 将过滤器字段滚动到视图中

【英文标题】：Flutter selection dialog - scroll filter field into view

【发布时间】：2020-01-16 20:38:18

【问题描述】：

我正在尝试构建一个颤振选择对话框。

对话框应该显示一个可滚动的列表。 对话框底部是用于过滤列表的文本字段。

这一切都很好。

问题是，当您单击过滤器文本字段时，会显示键盘，但它会覆盖文本字段。

我看过 SingleChildScrollView 但当然这不适用于列表视图。

我该如何解决这个问题？

布局是：

Dialog
 -> Heading
 -> SingleChildListView
     -> Column
        -> Expanded flex: 1
           -> ListView
        -> Text Field (for filter).

【参考方案1】：

我知道您的文本字段位于 ListView 的底部。在没有您的代码细节的情况下，我使用 flutter_typeahead 来模拟您的搜索过滤器操作

用 Container 包裹你的 Column 并设置适当的高度，在我的演示高度是 70 ，你可以用你的案例进行测试 类似的答案Flutter: ListView in a SimpleDialog 也建议用容器包装

完整代码

import 'package:flutter/material.dart';
import 'dart:math';
import 'package:flutter_typeahead/flutter_typeahead.dart';

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

class MyApp extends StatelessWidget 
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) 
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  


class MyHomePage extends StatefulWidget 
  MyHomePage(Key key, this.title) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();


class _MyHomePageState extends State<MyHomePage> 
  int _counter = 0;

  void _incrementCounter() 
    _showDialog();
    setState(() 
      // This call to setState tells the Flutter framework that something has
      // changed in this State, which causes it to rerun the build method below
      // so that the display can reflect the updated values. If we changed
      // _counter without calling setState(), then the build method would not be
      // called again, and so nothing would appear to happen.
      _counter++;
    );
  

  void _showDialog() 
    // flutter defined function
    showDialog(
      context: context,
      builder: (BuildContext context) 
        // return object of type Dialog
        return AlertDialog(
          title: new Text("Alert Dialog title"),
          content: Container(
            height: 70,
            child: TypeAheadField(
              getImmediateSuggestions: true,
              textFieldConfiguration: TextFieldConfiguration(
                autofocus: true,
                /*style: DefaultTextStyle.of(context)
                    .style
                    .copyWith(fontStyle: FontStyle.italic),*/
                decoration: InputDecoration(
                    border: OutlineInputBorder(),
                    hintText: 'What are you looking for?'),
              ),
              suggestionsCallback: (pattern) async 
                return await BackendService.getSuggestions(pattern);
              ,
              itemBuilder: (context, suggestion) 
                return ListTile(
                  leading: Icon(Icons.shopping_cart),
                  title: Text(suggestion['name']),
                  subtitle: Text('\$$suggestion['price']'),
                );
              ,
              onSuggestionSelected: (suggestion) 
               /* Navigator.of(context).push(MaterialPageRoute(
                    builder: (context) => ProductPage(product: suggestion)));*/
              ,
            ),
          ),
          actions: <Widget>[
            // usually buttons at the bottom of the dialog
            new FlatButton(
              child: new Text("Close"),
              onPressed: () 
                Navigator.of(context).pop();
              ,
            ),
          ],
        );
      ,
    );
  

  @override
  Widget build(BuildContext context) 
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          // Column is also layout widget. It takes a list of children and
          // arranges them vertically. By default, it sizes itself to fit its
          // children horizontally, and tries to be as tall as its parent.
          //
          // Invoke "debug painting" (press "p" in the console, choose the
          // "Toggle Debug Paint" action from the Flutter Inspector in android
          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
          // to see the wireframe for each widget.
          //
          // Column has various properties to control how it sizes itself and
          // how it positions its children. Here we use mainAxisAlignment to
          // center the children vertically; the main axis here is the vertical
          // axis because Columns are vertical (the cross axis would be
          // horizontal).
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );


  




class BackendService 
  static Future<List> getSuggestions(String query) async 
    await Future.delayed(Duration(seconds: 1));

    return List.generate(3, (index) 
      return 'name': query + index.toString(), 'price': Random().nextInt(100);
    );
  


class CitiesService 
  static final List<String> cities = [
    'Beirut',
    'Damascus',
    'San Fransisco',
    'Rome',
    'Los Angeles',
    'Madrid',
    'Bali',
    'Barcelona',
    'Paris',
    'Bucharest',
    'New York City',
    'Philadelphia',
    'Sydney',
  ];

  static List<String> getSuggestions(String query) 
    List<String> matches = List();
    matches.addAll(cities);

    matches.retainWhere((s) => s.toLowerCase().contains(query.toLowerCase()));
    return matches;
  

Demo ，您可以看到搜索和滚动正常工作。

【讨论】：

问题是我试图避免将列表视图设置为固定大小。我想我可以让它占屏幕高度的百分比，但这不是我理想的解决方案。