调整平面按钮的大小并在颤动中提供水平滚动选项

Posted 2023-02-23

【中文标题】调整平面按钮的大小并在颤动中提供水平滚动选项

【英文标题】：Resize Flat Button and give Horizontal Scrolling option in flutter

【发布时间】：2018-05-15 08:51:15

【问题描述】：

如果您可以在顶部看到，我创建了 4 列，其中包含一个平面按钮，其中包含一个图像和一个文本。我想为 Flat 按钮提供准确的宽度和高度，这可能吗？另外，我想进行水平滚动，以便可以在同一行中添加更多列。此外，单击图像，相应的列表应显示在下方。这是我到目前为止的代码。

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

    void main() => runApp(new MaterialApp(
        title: 'Booze Up',
      theme: new ThemeData(
  primarySwatch: Colors.red,
),
home: new MyHomePage('Booze Up'),
routes: <String,WidgetBuilder>
  "/MyHomePage2": (BuildContext context) => new MyHome()

));

       class MyHomePage extends StatelessWidget 

    int counter =0;
    String title;
    MyHomePage(this.title);

     @override
     Widget build(BuildContext context) 


        Text text = new Text("dev");
       Text text2 = new Text("Sneha");
       Text text3 = new Text("Prashant");

var pad = const EdgeInsets.all(10.0);

Padding pad1 = new Padding(child: text, padding:pad);
 Padding pad2 = new Padding(child: text2, padding:pad);
  Padding pad3 = new Padding(child: text3, padding:pad);

     ListView listView = new ListView(children: <Widget>[new 
     Image.asset('images/party.jpg'),pad1,pad2,pad3]);

  Drawer drawer = new Drawer(child:listView); 

// 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 new Scaffold(
  drawer: drawer,
  appBar: new 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: new Text(title),
  ),
  body:
  new Center(

    // Center is a layout widget. It takes a single child and positions it
    // in the middle of the parent.
    child: new Column(
             mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
        new Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
              new Icon(Icons.camera),
              new Padding(padding: new EdgeInsets.fromLTRB(0.0,0.0, 5.0,0.0)),
            new RaisedButton(
            color: Colors.black,
          child: 
          new Text(  'Party Home',
          style: new TextStyle(fontSize: 20.0,fontStyle: 
               FontStyle.italic,color: Colors.white),
                   ),
          onPressed: () 
                  Navigator.of(context).pushNamed("/MyHomePage2");
          ,                
       )]),
       new Row(
         mainAxisAlignment: MainAxisAlignment.center,
         children: <Widget>[
         new Icon(Icons.favorite),
        new Padding(padding: new EdgeInsets.fromLTRB(0.0,0.0, 5.0,0.0)),
        new Text(
          'Pub Hopping',
         style: new TextStyle(fontSize: 20.0,fontStyle: FontStyle.italic),

        ),
         ]),
        new Image.asset('images/party.jpg'),   
          ],
        )
        , 
    ),

  floatingActionButton: new FloatingActionButton(
    onPressed: null,
    child: new Icon(Icons.add),
  ), // This trailing comma makes auto-formatting nicer for build methods.
);
   


  

        class MyHome extends StatefulWidget
        
         @override
        State<StatefulWidget> createState() => new MyHomePage2();
         

        class MyHomePage2 extends State<MyHome> 
        List items = new List() ;


        @override
        Widget build(BuildContext context) 

var abc = MediaQuery.of(context).size;

print(abc.width);

var width = abc.width/4;

         Text text = new Text("Dev");
        Text text2 = new Text("Sneha");
        Text text3 = new Text("Prashant");
      Text text4 = new Text("Vikesh");

var pad = const EdgeInsets.all(10.0);

Padding pad1 = new Padding(child: text, padding:pad);
 Padding pad2 = new Padding(child: text2, padding:pad);
  Padding pad3 = new Padding(child: text3, padding:pad);
  Padding pad4 = new Padding(child: text4, padding:pad);

      ListView listView = new ListView(children: <Widget>[new 
      Image.asset('images/party.jpg'),pad1,pad2,pad3,pad4]);


     ListView listView2 = new ListView(children: <Widget>[new Text("Jacob 
        Creek"),new Text("Sula red"),new Text("Yellow tale"),new 
        Text("Chenin Blanc")]);

        Drawer drawer = new Drawer(child: listView);

return new Scaffold(
  drawer: drawer,

  appBar: new AppBar(
    title: new Text('Booze Up'),
  ),
  body:
     new Column(
      children: <Widget>[
        new Row(
           children: <Widget>[
                 new Column(
          children: <Widget>[
                  new FlatButton(child: new 
         Image.asset('images/party.jpg',width:width,height: 
          width),onPressed: buildlist('button1'),),
          new Text('Juice', style: new TextStyle(fontSize: 20.0,fontStyle: 
          FontStyle.italic)),        
          ]),
                new Column(
          children: <Widget>[
        new FlatButton(child: new 
       Image.asset('images/party.jpg',width:width,height: width),onPressed: 
        buildlist('button2')),
          new Text('Cocktail', style: new TextStyle(fontSize: 
         20.0,fontStyle: FontStyle.italic)) ,                     
          ]),
                  new Column(
          children: <Widget>[
      new FlatButton(child: new Image.asset('images/party.jpg',width:width,height: width),onPressed: buildlist('button3')),
          new Text('Moocktail', style: new TextStyle(fontSize: 20.0,fontStyle: FontStyle.italic)),
          ]),
                  new Column(
          children: <Widget>[
     new FlatButton(child: new Image.asset('images/party.jpg',width:width,height: width),onPressed: buildlist('button4')),
          new Text('Juice', style: new TextStyle(fontSize: 20.0,fontStyle: FontStyle.italic)),
          ])
           ]),
        new Expanded(
          child: new ListView(
            padding: new EdgeInsets.fromLTRB(10.0, 10.0, 0.0,10.0),
            children: items,
          ),
        )]
     ),
  floatingActionButton: new FloatingActionButton(
    onPressed: null,
    child: new Icon(Icons.add),
  ), // This trailing comma makes auto-formatting nicer for build methods.
);
            

buildlist(String s ) 

    print("entered buildlist"+ s);

  List refresh = new List();
  if(s=='button1')
  
  refresh = [
   new Refreshments("Watermelon",250),
    new Refreshments("Orange",275),
    new Refreshments("Pine",300),
    new Refreshments("Papaya",225),
     new Refreshments("Apple",250),
];
  
  else if(s=='button2')

     refresh = [
      new Refreshments("Pina Colada",250),
      new Refreshments("Bloody Mary",275),
      new Refreshments("Long Island Ice tea",300),
      new Refreshments("Screwdriver",225),
      new Refreshments("Fusion Cocktail",250),
];
    
    else if(s=='button3')
    
    refresh  = [
       new Refreshments("Virgin Pina Colada",250),
      new Refreshments("Virgin Mary",275),
       new Refreshments("Strawberry Flush",300),
      new Refreshments("Mango Diver",225),
      new Refreshments("Peach Delight",250),
];
    
    else
 refresh = [
       new Refreshments("Absolute",250),
       new Refreshments("Smirnoff",275),
        new Refreshments("White Mischief",300),
        new Refreshments("Romanov",225),
        new Refreshments("Blender's Pride",250),
];
    


 for(var item in refresh)
 
   items.add(new ItemsList(item));
 

  


                 

       class  Refreshments 
 
        String name;
          int price;

           Refreshments(this.name,this.price);
 


            class ItemsList extends StatelessWidget
      
            final Refreshments refreshments;

           ItemsList (this.refreshments);

      @override
        Widget build(BuildContext context) 
     return new ListTile(
      onTap: null,
      title: new Text(refreshments.name),
  );

         
        

【参考方案1】：

要获得精确的width 和height，请使用Container 作为FlatButton 的父级，它为您提供这些属性。 *Darky 指出使用SizedBox 是更好的解决方案。

使用ListView 并指定scrollDirection: Axis.horizontal 以启用水平滚动。

使用ListView.builder 使您能够循环浏览子小部件列表，这样您现在只需读取列表中小部件的索引即可与正在交互的小部件。

示例

import "package:flutter/material.dart";

class LetsParty extends StatefulWidget 
  @override
  _LetsPartyState createState() => new _LetsPartyState();


class _LetsPartyState extends State<LetsParty> 
  Image _partyImage = new Image.network(
      "http://www.freshcardsgifts.co.uk/images/_lib/animal-party-greetings-card-3003237-0-1344698261000.jpg");
  final GlobalKey<ScaffoldState> scaffoldKey = new GlobalKey<ScaffoldState>();

  @override
  Widget build(BuildContext context) 
    return new Scaffold(
      key: scaffoldKey,
      appBar: new AppBar(title: new Text("Let's Party"),),
      body: new ListView.builder(
          scrollDirection: Axis.horizontal,
          itemCount: 10, //add the length of your list here
          itemBuilder: (BuildContext context, int index) 
            return new Column(
              children: <Widget>[

                ///Flexible let's your widget flex in  the given space, dealing with the overflow you have
                //  new Flexible(child: new FlatButton(onPressed: ()=>print("You pressed Image No.$index"), child: _partyImage)),
                new Container(child: new FlatButton(onPressed: () =>
                    scaffoldKey.currentState.showSnackBar(new SnackBar(
                        content: new Text("You pressed Image No.$index"))),
                    child: _partyImage),
                  width: 100.0, height: 100.0,),
                //Exact width and height, consider adding Flexible as a parent to the Container
                new Text("Text$index")
              ],
            );
          ),
    );
  

【讨论】：

使用SizedBox 而不是Container 来调整孩子的大小。这样更清晰，有更多选择。

这是你给的一个非常好的demo。它删除了我的很多冗余代码。但是，buildlist 中的 setState 方法甚至在页面构建之前就被调用了，这是为什么呢？在这个问题中，我忘记了 setState()，后来我将它合并到我的程序中。请你帮忙。

@DivyangShah 很抱歉，我在您的代码中没有看到任何 setState

这就是我后来在发布此问题后包含的内容。主要问题是 buildlist() 甚至在页面加载之前就被调用了。我已将代码包含在 setState 内的 buildlist 中。Like buildlist() setState( () ...code);

这与你在这里问什么无关，也许用相关代码打开另一个问题。