Flutter 自定义SegmentControl

import 'package:flutter/material.dart';
import 'package:toofoo/common/base_component/base_image.dart';
import 'package:toofoo/common/base_component/base_text.dart';
import 'package:toofoo/common/color/colorsUtil.dart';
import 'package:toofoo/common/screenAdaper/ScreenAdaper.dart';

typedef OnChange = void Function(int index);

class SegmentedControl extends StatefulWidget {
  SegmentedControl({Key key, this.onChange,
  this.titleList});

  final OnChange onChange;
  final List<String> titleList ;

  @override
  SegmentedControlState createState() => SegmentedControlState();
}

class SegmentedControlState extends State<SegmentedControl> {

  int index ;

  @override
  void initState() {
    super.initState();

    index = 0;
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      height: 44,
      child: _segmentedWidget(),
    );
  }

  Widget _segmentedWidget(){
    return Stack(
      children: [
        _segmentedTitleWidget(),
        _indicatorWidget(),
      ],
    );
  }

  Widget _segmentedTitleWidget(){
    return Container(
      child: Row(
        children: _getTitleWidget(),
      ),
    );
  }

  List<Widget> _getTitleWidget(){
    List<Widget> list = [];
    for(int i = 0; i < widget.titleList.length;i++){
      Expanded title = Expanded(
        child: TextButton(
          onPressed: (){
            setState(() {
              index = i;
              if(widget.onChange != null){
                widget.onChange(i);
              }
            });
          },
          child: Container(
            alignment: Alignment.center,
            child: BaseText.baseText(widget.titleList[i], 18, i==index?'111E36':'6A7182',fontWeight: i==index?FontWeight.bold:null),
          ),
        ),
      );
      list.add(title);
    }
    return list;
  }
  
  Widget _indicatorWidget(){
     double indicatorWidth =  ScreenAdaper.screenWidth()/widget.titleList.length;
    return Container(
      margin: EdgeInsets.only(left: index*indicatorWidth+indicatorWidth/2-5,top: 34),
      child: BaseImage.getBaseImage('common/search_segment.png'),
    );
  }




}

SegmentedControl(
          titleList: ['歌单','歌曲','筛选'],
          onChange: (int index){

          },
 ),