Flutter实战视频-移动电商-19.首页_火爆专区界面布局编写

19.首页_火爆专区界面布局编写

看一下图片的效果

一个标题栏，下面是多行两列。里面可以用column布局，外面用Warp流式布局

有得小伙伴说这里可以用网格布局，网格布局的话还是有一定的效率问题。这里就用我们的流布局，还是很顺畅的

填一下上节课的坑，设置可选参数

service_method.dart 这里用花括号括起来就是个可选的参数了。

修改成可选参数后呢，我们在调用方法的时候就报错了。

我们只要修改为key/value的形式就可以了

火爆专区的请求数据

上拉刷新有几种方式

火爆专区主要的代码，这是之前的，现在要删掉了

//火爆专区 定义为动态的类
class HotGoods extends StatefulWidget {
  @override
  _HotGoodsState createState() => _HotGoodsState();
}

class _HotGoodsState extends State<HotGoods> {
  void initState() {
    super.initState();
    request('homePageBelowConten',formData:).then((val){
      print(val);
    });
  }
  @override
  Widget build(BuildContext context) {
    return Container(
      child:Text('')
    );
  }
}

我们在最上面定义两个变量。使用的是State For Widget的形式

定义一个内部的方法去获取远程数据，内部方法用下划线开头 _getHotGoods()

创建火爆专区的标题

//火爆专区的标题
  Widget hotTitle = Container(
    margin: EdgeInsets.only(top:10.0),//上边距
    alignment: Alignment.center,//居中对齐
    color: Colors.transparent,
    child: Text('火爆专区'),
  );

流式布局

流式布局的问题，如果数据是空 那么返回流式布局就会报错

所以我们需要判断数据的list的长度

把list包装成Widget

把商品的List<Map>的形式，转换成了 List<Widget>的形式

最终再返回我们的wrap布局

else的情况，当列表数据为空那么我们就返回一个空的Text widget

把标题和流式布局组合起来

调用加载数据的方法

测试效果展示

往下拖还有一些数据

标题加上内边距

边距稍微好看了点

最终代码

import 'package:flutter/material.dart';
import '../service/service_method.dart';
import 'package:flutter_swiper/flutter_swiper.dart';
import 'dart:convert';
import 'package:flutter_screenutil/flutter_screenutil.dart';
import 'package:url_launcher/url_launcher.dart';

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> with AutomaticKeepAliveClientMixin{

  int page=;
  List<Map> hotGoodsList=[];
  @override
  bool get wantKeepAlive => true;

  @override
  void initState() {
    super.initState();
    _getHotGoods();
    print('');
  }

  String homePageContent='正在获取数据';
  @override
  Widget build(BuildContext context) {
     var formData={'lon':'115.02932','lat':'35.76189'};//传一个经纬度过去，防止恶意下单
    return Scaffold(
      appBar: AppBar(title: Text('百姓生活+')),
      body: FutureBuilder(
        future: request('homePageContent',formData:formData),
        builder: (context, snapshot) {
          if(snapshot.hasData){
            var data=json.decode(snapshot.data.toString());
            List<Map> swiper=(data['data']['slides'] as List).cast();
            List<Map> navigatorList=(data['data']['category'] as List).cast();
            String adPicture=data['data']['advertesPicture']['PICTURE_ADDRESS'];
            String leaderImage=data['data']['shopInfo']['leaderImage'];
            String leaderPhone=data['data']['shopInfo']['leaderPhone'];
            List<Map> recommendList=(data['data']['recommend'] as List).cast();
            String floor1Title=data['data']['floor1Pic']['PICTURE_ADDRESS'];
            String floor2Title=data['data']['floor2Pic']['PICTURE_ADDRESS'];
            String floor3Title=data['data']['floor3Pic']['PICTURE_ADDRESS'];
            List<Map> floor1=(data['data']['floor1'] as List).cast();
            List<Map> floor2=(data['data']['floor2'] as List).cast();
            List<Map> floor3=(data['data']['floor3'] as List).cast();

            return SingleChildScrollView(
              child: Column(
                children: <Widget>[
                  SwiperDiy(swiperDateList: swiper),
                  TopNavigator(navigatorList:navigatorList ,),
                  AdBanner(adPicture:adPicture),
                  LeaderPhone(leaderImage: leaderImage,leaderPhone: leaderPhone,),
                  Recommend(recommendList:recommendList),
                  FloorTitle(picture_address: floor1Title,),//楼层1的标题图片
                  FloorContent(floorGoodsList: floor1),
                   FloorTitle(picture_address: floor2Title,),//楼层1的标题图片
                  FloorContent(floorGoodsList: floor2),
                   FloorTitle(picture_address: floor3Title,),//楼层1的标题图片
                  FloorContent(floorGoodsList: floor3),
                  _hotGoods()
                ],
              ),
            );
          }else{
            return Center(child: Text('加载中....'));
          }
        },
      ),
    );
  }

  void _getHotGoods(){
    var formData={'page',page};
    request('homePageBelowConten',formData:formData).then((val){
      var data=json.decode(val.toString());
      List<Map> newGoodsList=(data['data'] as List).cast();
      //把新的列表加到老的列表里面
      setState(() {
        hotGoodsList.addAll(newGoodsList);
        page++;
      });
    });
  }
  //火爆专区的标题
  Widget hotTitle = Container(
    margin: EdgeInsets.only(top:10.0),//上边距
    alignment: Alignment.center,//居中对齐
    color: Colors.transparent,
    padding: EdgeInsets.all(5.0),
    child: Text('火爆专区'),
  );

  Widget _wrapList(){
    if(hotGoodsList.length!=){
      List<Widget> listWidget=hotGoodsList.map((val){
        return InkWell(
          onTap: (){},
          child: Container(
            width: ScreenUtil().setWidth(),
            color: Colors.white,
            padding: EdgeInsets.all(5.0),//内边距
            margin: EdgeInsets.only(bottom: 3.0),
            child: Column(
              children: <Widget>[
                Image.network(val['image'],width: ScreenUtil().setWidth(),),//设置宽度防止超出边界
                Text(
                  val['name'],
                  maxLines: ,//只有一行
                  overflow: TextOverflow.ellipsis,//超出显示省略号的形式
                  style: TextStyle(color: Colors.pink,fontSize: ScreenUtil().setSp()),
                ),
                Row(
                  children: <Widget>[
                    Text('￥${val['mallPrice']}'),//商城价格
                    Text(
                      '￥${val['price']}',
                      style: TextStyle(color: Colors.black26,decoration: TextDecoration.lineThrough),//加上删除线的价格
                    )
                  ],
                )
              ],
            ),
          ),
        );
      }).toList();
      return Wrap(
        spacing: ,//每一行显示两列
        children: listWidget,
      );
    }else{
      return Text('');
    }
  }

  //组合火爆专区的标题和列表
  Widget _hotGoods(){
    return Container(
      child: Column(
        children: <Widget>[
          hotTitle,
          _wrapList()
        ],
      ),
    );
  }

}
//首页轮播插件
class SwiperDiy extends StatelessWidget {
  final List swiperDateList;
  //构造函数
  SwiperDiy({this.swiperDateList});

  @override
  Widget build(BuildContext context) {

    // print('设备的像素密度：${ScreenUtil.pixelRatio}');
    // print('设备的高：${ScreenUtil.screenWidth}');
    // print('设备的宽：${ScreenUtil.screenHeight}');

    return Container(
      height: ScreenUtil().setHeight(),//
      width:ScreenUtil().setWidth(),
      child: Swiper(
        itemBuilder: (BuildContext context,int index){
          return Image.network("${swiperDateList[index]['image']}",fit: BoxFit.fill,);
        },
        itemCount: swiperDateList.length,
        pagination: SwiperPagination(),
        autoplay: true,
      ),
    );
  }
}

class TopNavigator extends StatelessWidget {
  final List navigatorList;

  TopNavigator({Key key, this.navigatorList}) : super(key: key);

  Widget _gridViewItemUI(BuildContext context,item){
    return InkWell(
      onTap: (){print('点击了导航');},
      child: Column(
        children: <Widget>[
          Image.network(item['image'],width: ScreenUtil().setWidth()),
          Text(item['mallCategoryName'])
        ],
      ),
    );
  }
  @override
  Widget build(BuildContext context) {
    if(this.navigatorList.length>){
      this.navigatorList.removeRange(,this.navigatorList.length);//从第十个截取，后面都截取掉
    }
    return Container(
      height: ScreenUtil().setHeight(),//只是自己大概预估的一个高度，后续可以再调整
      padding: EdgeInsets.all(3.0),//为了不让它切着屏幕的边缘，我们给它一个padding
      child: GridView.count(
        crossAxisCount: ,//每行显示5个元素
        padding: EdgeInsets.all(5.0),//每一项都设置一个padding，这样他就不挨着了。
        children: navigatorList.map((item){
          return _gridViewItemUI(context,item);
        }).toList(),
      ),
    );
  }
}

class AdBanner extends StatelessWidget {
  final String adPicture;

  AdBanner({Key key, this.adPicture}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Image.network(adPicture),
    );
  }
}

//店长电话模块
class LeaderPhone extends StatelessWidget {
  final String leaderImage;//店长图片
  final String leaderPhone;//店长电话 

  LeaderPhone({Key key, this.leaderImage,this.leaderPhone}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      child: InkWell(
        onTap: _launchURL,
        child: Image.network(leaderImage),
      ),
    );
  }

  void _launchURL() async {
    String url = 'tel:'+leaderPhone;
    //String url = 'http://jspang.com';
    if(await canLaunch(url)){
      await launch(url);
    }else{
      throw 'url不能进行访问，异常';
    }
  }
}

//商品推荐
class Recommend extends StatelessWidget {
  final List recommendList;

  Recommend({Key key, this.recommendList}) : super(key: key);

  //商品标题
  Widget _titleWidget(){
    return Container(
      alignment: Alignment.centerLeft,//局长靠左对齐
      padding: EdgeInsets.fromLTRB(10.0, 2.0, , 5.0),//左上右下
      decoration: BoxDecoration(
        color: Colors.white,
        border: Border(
          bottom: BorderSide(width: 0.5,color: Colors.black12) //设置底部的bottom的边框，Black12是浅灰色
        ),
      ),
      child: Text(
        '商品推荐',
        style:TextStyle(color: Colors.pink)
      ),
    );
  }
  //商品单独项方法
  Widget _item(index){
    return InkWell(
      onTap: (){},//点击事件先留空
      child: Container(
        height: ScreenUtil().setHeight(),//兼容性的高度 用了ScreenUtil
        width: ScreenUtil().setWidth(),//750除以3所以是250
        padding: EdgeInsets.all(8.0),
        decoration: BoxDecoration(
          color: Colors.white,
          border: Border(
            left: BorderSide(width: ,color: Colors.black12)//右侧的 边线的样式 宽度和 颜色
          )
        ),
        child: Column(
          children: <Widget>[
            Image.network(recommendList[index]['image']),
            Text('￥${recommendList[index]['mallPrice']}'),
            Text(
              '￥${recommendList[index]['price']}',
              style: TextStyle(
                decoration: TextDecoration.lineThrough,//删除线的样式
                color: Colors.grey//浅灰色
              ),
            ),
          ],
        ),
      ),
    );
  }
  //横向列表方法
  Widget _recommendList(){
    return Container(
      height: ScreenUtil().setHeight(),
      child: ListView.builder(
        scrollDirection: Axis.horizontal,//横向的
        itemCount: recommendList.length,
        itemBuilder: (context,index){
          return _item(index);
        },
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      height: ScreenUtil().setHeight(),//列表已经设置为330了因为还有上面标题，所以要比330高，这里先设置为380
      margin: EdgeInsets.only(top: 10.0),
      child: Column(
       children: <Widget>[
          _titleWidget(),
          _recommendList()
       ],
      ),
    );
  }
}

//楼层标题
class FloorTitle extends StatelessWidget {
  final String picture_address;

  FloorTitle({Key key, this.picture_address}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: EdgeInsets.all(8.0),
      child: Image.network(picture_address),
    );
  }
}

//楼层商品列表
class FloorContent extends StatelessWidget {
  final List floorGoodsList;

  FloorContent({Key key, this.floorGoodsList}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Column(
        children: <Widget>[
          _firstRow(),
          _otherGoods()
        ],
      ),
    );
  }

 Widget _firstRow(){
   return Row(
     children: <Widget>[
       _goodsItem(floorGoodsList[]),
       Column(
         children: <Widget>[
          _goodsItem(floorGoodsList[]),
           _goodsItem(floorGoodsList[])
         ],
       )
     ],
   );
 }
 Widget _otherGoods(){
   return Row(
     children: <Widget>[
        _goodsItem(floorGoodsList[]),
        _goodsItem(floorGoodsList[])
     ],
   );
 }
  Widget _goodsItem(Map goods){
    return Container(
      width: ScreenUtil().setWidth(),
      child: InkWell(
        onTap: (){print('点击了楼层商品');},
        child: Image.network(goods['image']),
      ),
    );
  }
}

home_page.dart