Flutter移动电商实战 --（46）详细页_自定义TabBar Widget

主要实现详情和评论的tab

provide定义变量

自己做一个tab然后用provide去控制

定义两个变量来判断是左侧选中了还是右侧选中了。并定义一个方法来接受参数，修改是左侧还是右侧选中的状态值

新建组件页面

details_page/details_tabbar.dart

然后定义方法_myTabbarLeft

左侧tab的点击事件，调用provide内的change方法传入是left

把_myTabbarLeft方法复制一个改成_myTabbarRight然后把参数什么的也修改为右侧的

build内合并方法

显示声明两个变量 从provide中获取isLeft和isRight

详情添加引用这个组件

先引入组件：

import './details_page/details_tabbar.dart';

然后直接调用就可以了

修改成ListView组件，防止溢出

效果展示

最终代码：

provide/details_info.dart

import 'package:flutter/material.dart';
import '../model/details.dart';
import '../service/service_method.dart';
import 'dart:convert';

class DetailsInfoProvide with ChangeNotifier{
  //商品详情的变量
  DetailsModel goodsInfo=null;

  bool isLeft=true;
  bool isRight=false;
  //tabbar的切换方法
  changeLeftAndRight(String changeState){
    if(changeState=='left'){
      isLeft=true;
      isRight=false;
    }else{
      isLeft=false;
      isRight=true;
    }
    notifyListeners();//通知
  }

  //从后台获取商品数据
  getGoodsInfo(String id){
    var formData={'goodId':id};
    request('getGoodDetailById',formData:formData).then((val){
      var responseData=json.decode(val.toString());
      print(responseData);//打印出返回的json数据
      goodsInfo=DetailsModel.fromJson(responseData);

      notifyListeners();//通知
    });
  }
}

details_page/details_tabbar.dart

import 'package:flutter/material.dart';
import 'package:provide/provide.dart';
import '../../provide/details_info.dart';
import 'package:flutter_screenutil/flutter_screenutil.dart';

class DetailsTabbar extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Provide<DetailsInfoProvide>(
      builder: (context,child,val){
        var isLeft=Provide.value<DetailsInfoProvide>(context).isLeft;
        var isRight=Provide.value<DetailsInfoProvide>(context).isRight;

        return Container(
          margin: EdgeInsets.only(top:15.0),
          child: Row(
            children: <Widget>[
              _myTabbarLeft(context,isLeft),
              _myTabbarRight(context,isRight)
            ],
          ),
        );
      },
    );
  }

  Widget _myTabbarLeft(BuildContext context,bool isLeft){
    return InkWell(
      onTap: (){
        Provide.value<DetailsInfoProvide>(context).changeLeftAndRight('left');
      },
      child: Container(
        padding: EdgeInsets.all(10.0),
        alignment: Alignment.center,
         ScreenUtil().setWidth(375),
        decoration: BoxDecoration(
          color: Colors.white,
          border: Border(
            bottom: BorderSide(
               1.0,
              color: isLeft?Colors.pink:Colors.black12
            )
          )
        ),
        child: Text(
          '详情',
          style: TextStyle(
            color: isLeft?Colors.pink:Colors.black
          ),
        ),
      ),
    );
  }
  //右侧tabbar的方法
  Widget _myTabbarRight(BuildContext context,bool isRight){
    return InkWell(
      onTap: (){
        Provide.value<DetailsInfoProvide>(context).changeLeftAndRight('right');
      },
      child: Container(
        padding: EdgeInsets.all(10.0),
        alignment: Alignment.center,
         ScreenUtil().setWidth(375),
        decoration: BoxDecoration(
          color: Colors.white,
          border: Border(
            bottom: BorderSide(
               1.0,
              color: isRight?Colors.pink:Colors.black12
            )
          )
        ),
        child: Text(
          '评论',
          style: TextStyle(
            color: isRight?Colors.pink:Colors.black
          ),
        ),
      ),
    );
  }

}

details_page.dart

import 'package:flutter/material.dart';
import 'package:provide/provide.dart';
import '../provide/details_info.dart';
import './details_page/details_top_area.dart';
import './details_page/details_expain.dart';
import './details_page/details_tabbar.dart';

class DetailsPage extends StatelessWidget {
  final String goodsId;

  DetailsPage(this.goodsId);//flutter 1.2的最新的写法 构造函数

  @override
  Widget build(BuildContext context) {
 
    return Scaffold(
      appBar: AppBar(
        leading: IconButton(
          icon: Icon(Icons.arrow_back),
          onPressed: (){
            Navigator.pop(context);//返回上一个页面
          },
        ),
        title: Text('商品详细页'),
      ),
      body: FutureBuilder(
        future: _getBackInfo(context),
        builder: (context,snapshot){
          //判断是否有数据
          if(snapshot.hasData){
            //如果有数据返回一个Container
            return Container(
              child: ListView(
                children: <Widget>[
                  DetailsTopArea(),
                  DetailsExplain(),
                  DetailsTabbar()
                ],
              ),
            );
          }else{
            return Text('加载中......');//没有数据的情况
          }
        },
      ),
    );
  }

  Future _getBackInfo(BuildContext context) async{
    await Provide.value<DetailsInfoProvide>(context).getGoodsInfo(goodsId);
    //print('加载完成...........');
    return '完成加载';
  }

}

.