将base64字符串保存为图片的方法

import { buffer } from '@kit.ArkTS';
import { fileIo } from '@kit.CoreFileKit';
import { common } from '@kit.AbilityKit';
import { fileUri } from "@kit.CoreFileKit";
import { hilog } from '@kit.PerformanceAnalysisKit';

let context = getContext(this) as common.UIAbilityContext;
let filesDir = context.filesDir;

// data为需要转换的base64字符串，返回沙箱路径uri
export async function writeFile(data: string): Promise<string> {
  let uri = ''
  try {
    let filePath = filesDir + "/1.png";
    uri = fileUri.getUriFromPath(filePath);
    let file = fileIo.openSync(filePath, fileIo.OpenMode.READ_WRITE | fileIo.OpenMode.CREATE);
    console.info("file fd: " + file.fd);
    const reg = new RegExp("data:image/\\w+;base64,")
    const base64 = data.replace(reg, "");
    console.log("base64flag", base64)
    const dataBuffer = buffer.from(base64, 'base64')
    let writeLen = fileIo.writeSync(file.fd, dataBuffer.buffer);
    hilog.info(0xA0c0d0,'uri',uri)
    fileIo.closeSync(file);
  }
  catch (Error) {
    hilog.error(0xA0c0d0,'Error',Error.code)
  }
  return uri;
}