如何修复在尝试使用改进抛出OutOfMemoryError时抛出的OutOfMemoryError

Question

我正在使用改造来下载一些媒体文件，如视频，mp3，jpg，pdf，...在我的应用程序中。当我想下载一个55MB格式为mp4的大文件时，这是一个问题。当我想下载此文件时，我收到如下错误：

OutOfMemoryError threw while trying to throw OutOfMemoryError; no stack trace available

这是我的代码：

  private void downloadFile() {

    ArrayList<FileModel> filesInDB = G.bootFileFromFileDB();

    for (final FileModel fm : filesInDB) {

      APIService downloadService = ServiceGenerator.createServiceFile(APIService.class, "username", "password");

      //Id of apk file that you want to download
      Call<ResponseBody> call = downloadService.downloadFileWithDynamicUrlSync("file/download/" + String.valueOf(fm.getFileId()));
      call.enqueue(new Callback<ResponseBody>() {

        @Override
        public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
          if (response.isSuccess()) {

            Log.d("LOGOO", "server contacted and has file");

            boolean writtenToDisk = writeResponseBodyToDisk(response.body(), fm.getFileName(), fm.getFileExtension());

            response = null;


            Log.d("LOGOO", "file download was a success? " + writtenToDisk);


          } else {
            Log.d("LOGOO", "server contact failed");
          }
        }

        @Override
        public void onFailure(Call<ResponseBody> call, Throwable t) {
          Log.i("LOGO", "Error is : " + t.getMessage());

          Toast.makeText(ActivityInternet.this, R.string.internet_error, Toast.LENGTH_LONG).show();
          Intent intent = new Intent(ActivityInternet.this, ActivityStartup.class);
          startActivity(intent);
        }
      });
    }

这是我正在使用的'writeResponseBodyToDisk'方法：

  private boolean writeResponseBodyToDisk(ResponseBody body, String fileName, String fileExtension) {

    try {

      // Location to save downloaded file and filename
      File futureStudioIconFile = new File(G.DIR_APP + fileName + fileExtension);
      InputStream inputStream = null;
      OutputStream outputStream = null;
      try {
        byte[] fileReader = new byte[4096];
        long fileSize = body.contentLength();
        long fileSizeDownloaded = 0;
        inputStream = body.byteStream();
        outputStream = new FileOutputStream(futureStudioIconFile);
        while (true) {
          int read = inputStream.read(fileReader);
          if (read == -1) {
            break;
          }
          outputStream.write(fileReader, 0, read);
          fileSizeDownloaded += read;
          Log.d("LOGO", "file download: " + fileSizeDownloaded + " of " + fileSize);
        }
        outputStream.flush();
        return true;
      } catch (IOException e) {
        return false;
      } finally {
        if (inputStream != null) {
          inputStream.close();
        }
        if (outputStream != null) {
          outputStream.close();
        }
      }
    } catch (IOException e) {
      return false;
    }


  }

最后这是我的createServiceFile方法：

public static <S> S createServiceFile(Class<S> serviceClass, String username, String password) {
        if (username != null && password != null) {

            String credentials = username + ":" + password;
            final String basic =
              "Basic " + Base64.encodeToString(credentials.getBytes(), Base64.NO_WRAP);
            httpClient.addInterceptor(new Interceptor() {
                @Override
                public Response intercept(Chain chain) throws IOException {
                    Request original = chain.request();
                    Request.Builder requestBuilder = original.newBuilder()
                      .header("Authorization", basic)
                      .header("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,audio/mp4,image/jpeg,*/*;q=0.8")
                      .method(original.method(), original.body());
                    Request request = requestBuilder.build();
                    return chain.proceed(request);
                }
            });
        }
        OkHttpClient client = httpClient.build();
        Retrofit retrofit = builder.client(client).build();
        return retrofit.create(serviceClass);
    }

如果你能帮助我，我真的很感激:)

Answer 1

在改造中处理大文件下载时需要注意4件事：

1. 确保你在android:largeHeap="true"中使用AndroidManifest.xml作为<application>的属性。
2. 确保使用Retrofit中的@Streaming注释，以便流式传输解决方案而不是整体读取它，这会阻碍内存。
3. 使用AsyncTask中描述的this link处理响应。在你的情况下，这意味着从writeResponseBodyToDisk内部调用AsyncTask。
4. 最后要避免的是使用Level.BODY okhttp3日志拦截器。将它与流式响应一起使用仍然可以将整个响应体保留在内存中，从而抵消了改造提供的@Streaming支持的优势。