如何将music.mp3文件下载到android中的应用存储？

Question

Music files should be downloaded to the app itself, it shouldn't get stored on mobile memory (file manager or SD card).

Answer 1

FileManager Class to store mp3 file inside app folders.

public class FileManager {

    private final Context context;

    FileManager(Context context) {
        this.context = context;
    }

    public String getRootPath() {
    File file = new File(context.getFilesDir(),"");
    return file.getAbsolutePath();
}
public String getFilePath(String name) {
        File file = new File(context.getFilesDir(), name);
        return file.getAbsolutePath();
    }
  }

Download request

@RequiresApi(api = Build.VERSION_CODES.O)
    private void initDownload(String soundUri) {
        Log.d(TAG, "initDownload: " + soundUri);

        Retrofit retrofit = new Retrofit.Builder().baseUrl(BASE_URL).build();

        ApiService retrofitInterface = retrofit.create(ApiService.class);
        Call<ResponseBody> request = retrofitInterface.downloadFile(soundUri);

        request.enqueue(new Callback<ResponseBody>() {
        @Override
        public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
               if (response.body() != null) {
                    Thread thread = new Thread(() -> {
                        try {
                            saveVoice(response.body());
                        } catch (IOException e) {
                            Log.d(TAG, "onResponse: " + e);
                        }
                    });
                    thread.start();
                }
        }

        @Override
        public void onFailure(Call<ResponseBody> call, Throwable t) {

        }
    });
    }




@RequiresApi(api = Build.VERSION_CODES.O)
private void saveVoice(ResponseBody body) throws IOException {
    try {
        String mp3Key= "YOUR_KEY_TO_STORE_FILE";

        int count;
        byte data[] = new byte[1024 * 4];
        InputStream bis = new BufferedInputStream(body.byteStream(), 1024 * 8);
        File outputFile = new File(fileManager.getRootPath(), voiceKey);
        OutputStream output = new FileOutputStream(outputFile);
        long startTime = System.currentTimeMillis();
        int timeCount = 1;
        while ((count = bis.read(data)) != -1) {

            long currentTime = System.currentTimeMillis() - startTime;

            if (currentTime > 1000 * timeCount) {

                timeCount++;
            }
            output.write(data, 0, count);
        }
        output.flush();
        output.close();
        bis.close();
    } catch (Exception e) {
        Log.d(TAG, "saveVoice: " + e);
    }
}

After successfully download you can read file with the key that you wrote file to app storage. To do that:

String filePath = fileManager.getFilePath(mp3Key); // filePath returns local url of file

For example, you can do:

 mediaPlayer.setDataSource(filePath );