HarmonyOS 如何将media文件夹中的png图片转为base64字符串？

可以参考下getMediaContentBase64这个api进行转换，请参考：https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-resource-manager-V5#getmediacontentbase649

demo:

import { BusinessError } from '@ohos.base';
import { common } from '@kit.AbilityKit';

//自定义组件
@Component
struct Child {
  @State private text: string = '初始值'
  private controller: ChildController = new ChildController();

  aboutToAppear() {
    if(this.controller) {
      this.controller.changeText = this.changeText
    }
  }

  private changeText = (value: string) =>{
    this.text = value
  }

  build() {
    Column() {
      Text(this.text)
    }
  }
}

class ChildController {
  changeText = (value: string) => {
  }
}

export let ChildRef = new ChildController()

@Entry
@Component
struct Parent {
  // ChildRef = new ChildController()
  @State noShow: boolean = false
  private context = getContext(this) as common.UIAbilityContext;

  aboutToAppear(): void {

    try {
      this.context.resourceManager.getMediaContentBase64($r('app.media.startIcon').id, (error: BusinessError, value: string) => {
        if (error != null) {
          console.error("error is " + error);
        } else {
          let media = value;
          //base64编码的值
          console.info(media)
        }
      });
    } catch (error) {
      let code = (error as BusinessError).code;
      let message = (error as BusinessError).message;
      console.error(`callback getMediaContentBase64 failed, error code: ${code}, message: ${message}.`);
    }
  }

  build() {
    Column() {
      Text('获取Child的exposeMethods!').fontSize('18vp').fontColor(Color.Gray)
      Divider()
      Child({ controller: ChildRef })
      Child()
      Button('Parent调用childe的changeText').onClick(() => {
        ChildRef.changeText('Parent调用childer的changeText')
      })

    }
  }
}