为什么我的代码在我的 react-native-ffmpeg 承诺之后没有运行？答案

【问题标题】：Why my code doesn't run after my react-native-ffmpeg promise?为什么我的代码在我的 react-native-ffmpeg 承诺之后没有运行？
【发布时间】：2021-04-13 00:52:24
【问题描述】：

视频和音频下载后，我使用react-native-ffmpeg 得到最终的视频文件。有用。当我得到最终的视频文件时，我想删除 1.mp4 和 2.mp4。问题是 await getFinalVideo(path, path1, path2, titleVideo) 之后的代码没有运行。 1.mp4 和 2.mp4 仍然存在于文件系统中。如何解决？我的错在哪里？

import React from "react";
import { PermissionsAndroid } from "react-native";
import RNFS from "react-native-fs";
import { LogLevel, RNFFmpeg } from "react-native-ffmpeg";

// url1  video , url2 audio
export const fetchDashFile = async (url1, url2, title) => {
  let options1 = {
    method: "GET",
    headers: {},
  };
  let options2 = {
    method: "GET",
    headers: {},
  };

  let path = RNFS.DownloadDirectoryPath + "/";
  let path1 = path + "1" + ".mp4";
  let path2 = path + "2" + ".mp4";

  const beginVideo = (res) => {
    console.log("start download video file");
  };
  const beginAudio = (res) => {
    console.log("start download audio file");
  };

  const progressVideo = (res) => {
    let percentage = ((100 * res.bytesWritten) / res.contentLength) | 0;
    console.log(percentage);
  };

  const progressAudio = (res) => {};

  let DownloadFileOptions1 = {
    fromUrl: url1,
    toFile: path1,
    headers: options1.headers,
    background: true,
    connectionTimeout: 50,
    progressInterval: 1,
    progressDivider: 10,
    begin: beginVideo,
    progress: progressVideo,
  };
  let DownloadFileOptions2 = {
    fromUrl: url2,
    toFile: path2,
    headers: options2.headers,
    background: true,
    connectionTimeout: 50,
    progressInterval: 1,
    progressDivider: 10,
    begin: beginAudio,
    progress: progressAudio,
  };

  try {
    await Promise.all([
      RNFS.downloadFile(DownloadFileOptions1).promise,
      RNFS.downloadFile(DownloadFileOptions2).promise,
    ]);

    let titleVideo = Date.now().toString();
    await getFinalVideo(path, path1, path2, titleVideo);

    if (RNFS.exists(path1)) {
      console.log("delete 1");
      await RNFS.unlink(path1);
    }
    if (RNFS.exists(path2)) {
      console.log("delete 2");
      await RNFS.unlink(path2);
    }
  } catch (e) {
    alert("error,please try again");
  }
};

function getFinalVideo(path, path1, path2, name) {
  let command =
    "-i " + path1 + " -i " + path2 + " -c copy " + path + name + ".mp4";
  return new Promise((resovle, reject) => {
    RNFFmpeg.executeAsync(command, (completedExecution) => {
      if (completedExecution.returnCode === 0) {
        console.log("FFmpeg process completed successfully");
      } else {
        console.log(
          `FFmpeg process failed with rc=${completedExecution.returnCode}.`
        );
      }
    })
      .then((executionId) => {
        console.log(executionId);

        Promise.resolve("success");
      })
      .catch((e) => {
        console.log("wrong happened when doing ffmpeg" + e);
        Promise.reject(e);
      });
  });
}

【问题讨论】：

标签： react-native async-await react-native-fs

【解决方案1】：

我太傻了。在删除文件之前，需要等待ffmpeg工作完成！我对 Promise 有一些误解。所以这里是正确的代码。

...
  let titleVideo = Date.now().toString()
    await getFinalVideo(path, path1, path2, titleVideo)
...


async function getFinalVideo(path, path1, path2, name) {
  let command = '-i ' + path1 + ' -i ' + path2 + ' -c copy ' + path + name + '.mp4'
  await RNFFmpeg.executeAsync(command, completedExecution => {
    if (completedExecution.returnCode === 0) {
      console.log("FFmpeg process completed successfully");

    } else {
      console.log(`FFmpeg process failed with rc=${completedExecution.returnCode}.`)

    }
  })
    .then(executionId => {
      console.log(executionId)
     // RNFFmpeg.cancelExecution(executionId)



    })
    .catch(e => {
      console.log('wrong happened when doing ffmpeg' + e)
    })

【讨论】：