根据该问题，您的JSON数组有4个对象，但是只有3个对象具有称为 resultlist &的嵌套数组.还没有1个对象.

According to the problem, your JSON array has 4 objects but only 3 of them have nested array called resultlist & 1 object hasn't.

{
    "img": "https://www.act.com/image/catalog/cmsblock/Powerbank10.jpg",
    "product_id": 187,
    "sort_order": 1,
    "status": true,
    "type": "middleimage",
}

这会导致错误 undefined不是对象(评估"item.resultlist.map")，因为您需要一个数组才能在JS中使用 map .但是该对象没有结果列表.

That's cause error undefined is not an object (evaluating 'item.resultlist.map') because you need an array in order to used map in JS. But that object hasn't resultlist.

这是您需要从后端处理的事情.如果没有，则可以通过添加 resultlist:[] 来过滤该对象或更改该对象的结构，如下所示.

That is something you need to handle from the backend. If not you can filtered that object or change structure of that object by adding resultlist:[] as below.

import * as React from "react";
import { Text, View, StyleSheet } from "react-native";

export default class App extends React.Component {
  state = {
    data: [
      {
        resultlist: [
          {
            img:
              "https://www.act.com/image/cache/catalog/new%20thumbnails/Mifa%20A1BlacjkThumbnail-600x600.jpg",
            name: "Mifa F1",
            product_id: 87,
            type: "product"
          },
          {
            category_id: 20,
            img: "https://www.achhacart.com/image/catalog/cmsblock/hgb5.png",
            name: "Earphone",
            type: "category"
          },
          {
            img: "https://www.achhacart.com/image/catalog/cmsblock/air.gif",
            name: "Air Purifier",
            product_id: 87,
            type: "product"
          },
          {
            img:
              "https://www.achhacart.com/image/catalog/cmsblock/Powerbank10.jpg",
            name: "Powerbank",
            product_id: 87,
            type: "product"
          }
        ],
        sort_order: 0,
        status: true,
        type: "product"
      },
      {
        img: "https://www.act.com/image/catalog/cmsblock/Powerbank10.jpg",
        product_id: 187,
        sort_order: 1,
        status: true,
        type: "middleimage"
      },
      {
        resultlist: [
          {
            img:
              "https://www.act.com/image/cache/catalog/new%20thumbnails/Mifa%20A1BlacjkThumbnail-600x600.jpg",
            name: "Mifa A1 Black",
            product_id: 87,
            type: "product"
          },
          {
            category_id: 20,
            img: "https://www.act.com/image/catalog/cmsblock/hgb5.png",
            name: "Earphones",
            type: "category"
          },
          {
            img: "https://www.act.com/image/catalog/cmsblock/air.gif",
            name: "Air Purifiers",
            product_id: 87,
            type: "product"
          },
          {
            img: "https://www.act.com/image/catalog/cmsblock/Powerbank10.jpg",
            name: "Powerbanks",
            product_id: 87,
            type: "product"
          }
        ],
        sort_order: 2,
        status: true,
        type: "product"
      },
      {
        resultlist: [
          {
            image:
              "https://www.act.com/simage/catalog/1AA/WeChatImage_20191228151402.jpg",
            link: "",
            title: "slider1"
          },
          {
            image:
              "https://www.act.com/staging-achhamall.com/image/catalog/1accc/WeChatImage_20191231125513.jpg",
            link: "",
            title: "slider2"
          }
        ],
        sort_order: 3,
        status: true,
        type: "slider"
      }
    ]
  };

  render() {
    let newArray = this.state.data.filter(obj => obj.resultlist);
    return (
      <View style={styles.container}>
        {newArray.map((item, i) => (
          <View>
            <Text key={i} style={{color: 'red'}}>{item.type}</Text>
            {item.resultlist.map((sub, index) => (
              <Text key={index}>{sub.name}</Text>
            ))}
          </View>
        ))}
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: "#ecf0f1",
    padding: 8
  }
});

希望这对您有所帮助.随时有疑问

Hope this helps you. Feel free for doubts