【HarmonyOS NEXT】如何读取Raw下的JSON文件内容

【HarmonyOS NEXT】如何读取Raw下的JSON文件内容

一、问题背景：

读取工程中/resources下json文件，json文件推荐放在rawfile路径下，通过getRawFileContent接口访问。但是通过该接口拿到的是Uint8Array类型数据，那怎么拿到JSON的文本内容？

二、解决方案：

1.首先通过getRawFileContent拿到文件的字节流内容。

getContext().resourceManager.getRawFileContent("vibration.json")

2.通过util.TextDecoder设置编码，解析字节流内容转化为string文本。

import { util, buffer } from '@kit.ArkTS';

        let decoder = util.TextDecoder.create('utf-8');
        let json = decoder.decodeToString(rawFile);

三、源码示例：

JSONTestPage.ets

import { BusinessError } from '@kit.BasicServicesKit';
import { util, buffer } from '@kit.ArkTS';

@Entry
@Component
struct JSONTestPage {

  private TAG: string = "JSONTestPage";
  @State showText: string = "";

  aboutToAppear(): void {
    this.getRawJson();
  }

  /**
   * 获取JSON
   */
  private getRawJson(){
    try {
      getContext().resourceManager.getRawFileContent("vibration.json").then((value: Uint8Array) => {
        let rawFile = value;
        let decoder = util.TextDecoder.create('utf-8');
        let json = decoder.decodeToString(rawFile);
        console.info(this.TAG, "json: " + json);
        this.showText = json;
      }).catch((error: BusinessError) => {
        console.error("getRawFileContent promise error is " + error);
      });
    } catch (error) {
      let code = (error as BusinessError).code;
      let message = (error as BusinessError).message;
      console.error(`promise getRawFileContent failed, error code: ${code}, message: ${message}.`);
    }
  }

  build() {
    Scroll(){
      Row() {
        Text(this.showText)
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
      }
    }
    .height('100%')
    .width('100%')
  }
}

vibration.json

{
  "MetaData": {
    "Create": "2023-01-09",
    "Description": "a haptic case",
    "Version": 1.0,
    "ChannelNumber": 1
  },
  "Channels": [
    {
      "Parameters": {
        "Index": 0
      },
      "Pattern": [
        {
          "Event": {
            "Type": "transient",
            "StartTime": 0,
            "Parameters": {
              "Frequency": 31,
              "Intensity": 100
            }
          }
        },
        {
          "Event": {
            "Type": "continuous",
            "StartTime": 40,
            "Duration": 54,
            "Parameters": {
              "Frequency": 30,
              "Intensity": 38,
              "Curve": [
                {
                  "Time": 0,
                  "Frequency": 0,
                  "Intensity": 0
                },
                {
                  "Time": 1,
                  "Frequency": 15,
                  "Intensity": 0.5
                },
                {
                  "Time": 40,
                  "Frequency": -8,
                  "Intensity": 1.0
                },
                {
                  "Time": 54,
                  "Frequency": 0,
                  "Intensity": 0
                }
              ]
            }
          }
        }
      ]
    }
  ]
}