Eu tenho uma chamada HTTP de clientes trabalhando usando as classes apache padrão, mas estou tentando criar uma classe Volley personalizada para lidar com isso. Aqui está o código para a chamada padrão:

HttpURLConnection conn = (HttpURLConnection) new URL(strUrl).openConnection();
conn.setDoOutput(true);
conn.setDoInput(true);
conn.setConnectTimeout(30000);
conn.setUseCaches(true);
conn.setRequestMethod("POST");
conn.setRequestProperty("Authorization", "Token " + m_apiKey);
conn.setRequestProperty("Accept", "text/plain , application/json");
conn.setRequestProperty("Connection", "Keep-Alive");
conn.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + strBoundary);
conn.connect();


// **** Start content wrapper:
DataOutputStream request = new DataOutputStream(conn.getOutputStream());

request.writeBytes("\r\n--" + strBoundary + "\r\n");
request.writeBytes("Content-Disposition: form-data; name=\"" + attachmentName + "\";filename=\"" + imageFileName + "\"" + "\r\n");
request.writeBytes("Content-Type: image/jpeg " + "\r\n");
request.writeBytes("\r\n");
request.write(baos.toByteArray());

// **** End content wrapper:
request.writeBytes("\r\n--"+ strBoundary + "--\r\n");

// Flush output buffer:
request.flush();request.close();

Não sei como fazer o resto, mas é isso que tenho para o Volley que não está funcionando. Eu já fiz Multipart antes, mas não com limite e neste formato estranho.

classe pública ImageMultiRequest estende StringRequest {final String BOUNDARY = "something"; String final crlf = "\ r \ n"; String final twoHyphens = "-";

private final MultipartEntityBuilder entityBuilder = MultipartEntityBuilder.create();

private Response.Listener<String> mListener = null;
private Response.ErrorListener mEListener;
//
private final File mFilePart;
private Map<String, String> parameters;
private Map<String, String> header;
MultipartEntity entity = new MultipartEntity();
protected String apiKey;
ByteArrayOutputStream bos;

public ImageMultiRequest(String apiKey, String url, Listener<String> rListener, ErrorListener eListener, File file) {
    super(Method.POST, url, rListener, eListener);
    setShouldCache(false);
    this.apiKey = apiKey;
    this.bos = bos;
    mListener = rListener;
    mEListener = eListener;
    mFilePart = file;
    entityBuilder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
    entityBuilder.setBoundary(BOUNDARY);
    buildMultipartEntity();
}

@Override
public String getBodyContentType() {
    return "multipart/form-data; boundary=" + BOUNDARY + "; charset=utf-8";
}

/**
 * Overrides the base class to add the Accept: application/json header
 */
@Override
public Map<String, String> getHeaders() throws AuthFailureError {

    Map<String, String> headers = super.getHeaders();

    if (headers == null || headers.equals(Collections.emptyMap())) {
        headers = new HashMap<String, String>();
    }
    headers.put("Content-Type", "multipart/form-data;boundary=" + BOUNDARY+ "; charset=utf-8");
    headers.put("Connection", "Keep-Alive");
    headers.put("Accept", "text/plain , application/json");
    headers.put("Authorization", "Token " + apiKey);
    return headers;
}

@Override
public byte[] getBody() throws AuthFailureError {
    buildMultipartEntity();

    ByteArrayOutputStream bos = new ByteArrayOutputStream();

    try {
        entityBuilder.build().writeTo(bos);
    } catch (IOException e) {
        VolleyLog.e("IOException writing to ByteArrayOutputStream");
    }
    return bos.toByteArray();
}

private void buildMultipartEntity() {
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    entityBuilder.addPart("Content-Type: image/jpeg " + crlf + crlf, new ByteArrayBody(bos.toByteArray(), "car"));

  }
}

===================================================

SOLUÇÃO Com base na resposta abaixo

Aqui está o que eu criei que funcionou para isso e possivelmente outros problemas com o arquivo de várias partes incorporado ao Corpo do Conteúdo

package com.cars.android.common.volley;

import com.android.volley.AuthFailureError;
import com.android.volley.Response;
import com.android.volley.Response.ErrorListener;
import com.android.volley.Response.Listener;
import com.android.volley.VolleyLog;
import com.android.volley.toolbox.StringRequest;

import org.apache.http.HttpEntity;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.HttpMultipartMode;
import org.apache.http.entity.mime.MultipartEntity;
import org.apache.http.entity.mime.MultipartEntityBuilder;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

public class ImageMultiRequest extends StringRequest {
    final String BOUNDARY = "myboundary";

    private final MultipartEntityBuilder entityBuilder = MultipartEntityBuilder.create();
    HttpEntity entity = new MultipartEntity();

    private Response.Listener<String> mListener = null;
    private Response.ErrorListener mEListener;
    //
    private final File mFilePart;
    protected String apiKey;

    public ImageMultiRequest(String apiKey, String url, Listener<String> rListener, ErrorListener eListener, File file) {
        super(Method.POST, url, rListener, eListener);
        setShouldCache(false);
        this.apiKey = apiKey;
        mListener = rListener;
        mEListener = eListener;
        mFilePart = file;
        entityBuilder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
        entityBuilder.setBoundary(BOUNDARY);

        ContentType contentType = ContentType.create("image/png");
        entityBuilder.addBinaryBody("file", file, contentType, "car");
        entity = entityBuilder.build();
    }

    @Override
    public String getBodyContentType() {
        return entity.getContentType().getValue();
    }

    /**
     * Overrides the base class to add the Accept: application/json header
     */
    @Override
    public Map<String, String> getHeaders() throws AuthFailureError {

        Map<String, String> headers = super.getHeaders();

        if (headers == null || headers.equals(Collections.emptyMap())) {
            headers = new HashMap<String, String>();
        }
        headers.put("Content-Type", "multipart/form-data;boundary=" + BOUNDARY+ "; charset=utf-8");
        headers.put("Connection", "Keep-Alive");
        headers.put("Accept", "text/plain , application/json");
        headers.put("Authorization", "Token " + apiKey);
        return headers;
    }

    @Override
    public byte[] getBody() throws AuthFailureError {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();

        try {
            entity.writeTo(bos);
        } catch (IOException e) {
            VolleyLog.e("IOException writing to ByteArrayOutputStream");
        }
        return bos.toByteArray();
    }

}