flutter之从零搭建小米商城APP（三）首页的搭建

1.公共组件HeaderNav

下面是HeaderNav.dart

import 'package:flutter/material.dart';

class HeaderNav extends StatefulWidget {
  final Container left;
  final Container right;
  final Container content; //接受三个从父组件的传递过来的值，分别是left ，content，right，代表左，中，右
  HeaderNav({Key key, this.left, this.content, this.right}) : super(key: key);
  @override
  createState() => new HeaderComponent();
}

class HeaderComponent extends State<HeaderNav> {
  @override
  Widget build(BuildContext context) {
    return Container(
      decoration: new BoxDecoration(color: Color(0xfff2f2f2)),
      height: 40,
      padding: EdgeInsets.fromLTRB(0, 5, 0, 5),
      child: Row(
        children: <Widget>[
          Expanded(
            child: widget.left,
            flex: 1,
          ),
          Expanded(child: widget.content, flex: 6),
          Expanded(
            child: widget.right,
            flex: 1,
          )
        ],
      ),
    );
  }
}

2.home.dart

import 'package:flutter/material.dart';
import 'package:mi_shop/components/HeaderNav.dart';
import 'package:mi_shop/http/index.dart';
import 'package:mi_shop/http/api.dart';
import 'package:mi_shop/components/Nav.dart';

class Home extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return new Page();
  }
}

class Page extends State<Home> {
  @override
  Widget build(BuildContext context) {
    return layout(context);
  }

  Widget layout(BuildContext context) {
    return new MaterialApp(
      home: new Scaffold(
          // appBar: new AppBar(
          //   title: new Text('Welcome to Home'),
          // ),
          body: new Container(
        child: new Column(
          children: <Widget>[
            new HeaderNav(
                left: Container(
                  child: Image(
                    image: new AssetImage('images/logo.png'),
                    height: 15,
                  ),
                ),
                content: Container(
                  decoration: new BoxDecoration(
                      border:
                          new Border.all(width: 1, color: Color(0xffe5e5e5)),
                      borderRadius: BorderRadius.all(Radius.circular(2.0))),
                  child: Scaffold(
                    body: Row(
                      children: <Widget>[
                        Container(
                          child: Icon(Icons.search,
                              color: Color(0x4D000000), size: 20),
                          margin: EdgeInsets.fromLTRB(5, 0, 3, 0),
                        ),
                        Expanded(
                          child: new TextField(
                            decoration: new InputDecoration(
                              hintText: '搜索商品名称',
                              hintStyle: new TextStyle(
                                  fontSize: 13.0, color: Color(0x4D000000)),
                              fillColor: Colors.white, // 背景颜色
                              filled: true, // 支持背景颜色
                              contentPadding:
                                  const EdgeInsets.symmetric(vertical: 4),
                              border: OutlineInputBorder(
                                  borderSide: BorderSide.none,
                                  // borderSide: BorderSide(color: Color(0xffe5e5e5)),
                                  borderRadius: BorderRadius.circular(3)),
                            ),
                          ),
                        ),
                      ],
                    ),
                  ),
                ),
                right: Container(
                  child: Image(
                    image: new AssetImage('images/user.png'),
                    height: 18,
                  ),
                )),
          ],
        ),
      )),
    );
  }
}

3.成果

下方框中即为实现效果，left对应mi的图标，content对应中间输入框，right对应人的logo

4.注意的点

1）首先引入本地图片，在根目录下创建文件夹images，然后再根目录下的pubspec.yaml下引入，截图都写出，然后按上面代码写的直接引入就行，两步缺一不可


2）其次本想使用TextField 的prefixIcon来实现再输入框前缀图标，但发现这个prefixIcon的padding设置只能为正数，所以设置就没用，然后图标与搜字隔了很远，因为他这个有默认值，改变不了，真的鸡肋，但是我真的骂了一小时，找了很多文档，才找到同道说改不了，垃圾！就只有用一个容器包含一个图标，一个输入框，才解决，心累，先写这么多，后续完善。