Flutter 在颤振中使用Img的自定义滑块

当我更改滑块上的值时，我尝试返回并显示图像，但出现了一些错误 这是代码滑块

图像是我想在屏幕上显示的模板

import 'package:flutter/material.dart';
import 'package:haphy_by_aquasense/Pain/ui/widgets/text_and_img.dart';

class PainScale extends StatefulWidget {
  @override
  State createState() => _Painscale();
}

class _Painscale extends State<PainScale>{
  double pain_value = 0.0;
  String pain_text = "No me duele";

  @override
  Widget build(BuildContext context) {

    final text_pain = Container(
      height: 100,
      width: 400,

      margin: EdgeInsets.only(
        top: 150,
        right: 50,
      ),
      child: Text(
        pain_text,
      ),

    );

    final pain_scale_slider = Container(
      child: Slider(
        min: 0,
        max: 10,
        value: pain_value,
        onChanged: (value) {
          setState(() {
            pain_value = value;
            if(pain_value >= 0.0 && pain_value <= 2.0){
                TextAndImgPain("Me duele", "assets/img/escala1-2.png");
            }
            if(pain_value >= 2.0 && pain_value <= 4.0){
              TextAndImgPain("Me duele", "assets/img/escala3-4.png");
            }
          });
        },
      ),
    );

    return Stack(
      alignment: Alignment.center,
      children: [
        TextAndImgPain("Me duele", "assets/img/escala3-4.png"),
        pain_scale_slider
      ],
    );
  }
}

在这个img中是屏幕，但是我想在滑块的值改变时改变img

---

如果您想显示图像是否疼痛值正在改变，那么为什么不使用

    onChanged: (value) {
      setState(() {
        pain_value = value;
        if(pain_value >= 0.0 && pain_value <= 2.0){
            TextAndImgPain("Me duele", "assets/img/escala1-2.png");
        } else if(pain_value > 2.0 && pain_value <= 4.0){
          TextAndImgPain("Me duele", "assets/img/escala3-4.png");
        } else {'default value here'}
      });
    },

onChanged:（值）{
设置状态（）{
痛苦值=价值；
如果（pain_值>=0.0&&pain_值2.0&&pain_值=0.0&&pain_值=2.0&&pain_值，问题是它甚至不会更改图像或文本
    onChanged: (value) {
      setState(() {
        pain_value = value;
        if(pain_value >= 0.0 && pain_value <= 2.0){
            TextAndImgPain("Me duele", "assets/img/escala1-2.png");
        } else if(pain_value > 2.0 && pain_value <= 4.0){
          TextAndImgPain("Me duele", "assets/img/escala3-4.png");
        } else {'default value here'}
      });
    },

onChanged: (value) {
      setState(() {
        pain_value = value;
        if(pain_value >= 0.0 && pain_value <= 2.0){
            TextAndImgPain("Me duele", "assets/img/escala1-2.png");
        }
        if(pain_value >= 2.0 && pain_value <= 4.0){
          TextAndImgPain("Me duele", "assets/img/escala3-4.png");
        }
      });
    },