保存volley http stream / octet byte []对pdf文件的响应

Question

我正在开发一个需要从api保存pdf文件的Android应用程序。所以我不得不将Request volley类扩展为ByteArray类：

"Apples are good for health" , "I live in America" , "I love Mangoes and Apples and Strawberries." , "Mangoes and Apples and Honey"

我的Activity我正在调用ByteArrayRequest来执行api请求：

private void getCarnePDF（final int empreendimento，final int coligada，final String quadra，final String lote）{     RequestQueue requestQueue;     ByteArrayRequest请求;

package br.com.tarcisojunior.myapp;

import android.support.annotation.NonNull;

import com.android.volley.NetworkResponse;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.toolbox.HttpHeaderParser;

/**
 * Created by tarcisojunior on 18/04/18.
 */

public class ByteArrayRequest extends Request<byte[]> {
    private final Response.Listener<byte[]> mListener;


    public ByteArrayRequest(String url, Response.Listener<byte[]> listener,
                       Response.ErrorListener errorListener) {
        this(Method.GET, url, listener, errorListener);
    }

    public ByteArrayRequest(int method, String url, Response.Listener<byte[]> listener, Response.ErrorListener errorListener) {
        super(method, url, errorListener);
        mListener = listener;

    }


    @Override
    protected Response parseNetworkResponse(NetworkResponse response) {
        return Response.success(response.data, HttpHeaderParser.parseCacheHeaders(response));
    }

    @Override
    protected void deliverResponse(byte[] response) {
        if(null != mListener){
            mListener.onResponse(response);
        }
    }

    @Override
    public String getBodyContentType() {
        return "application/octet-stream";
    }

}

}

并且在监听器中saveToFile函数应该创建pdf文件。已创建pdf文件，但引发错误“无法打开文件”。这是我的saveToFile函数：

requestQueue = Volley.newRequestQueue(this);

request = new ByteArrayRequest(Request.Method.GET, getString(R.string.baseUrl) + getString(R.string.carnePdfUrl),
        new Response.Listener<byte[]>() {
            @Override
            public void onResponse(byte[] response) {
                Log.i("getBilletCard", response.toString());
                try {
                    byte[] bytes = response;
                    saveToFile(bytes, "card.pdf");
                }catch (Exception e){
                    Toast.makeText(BilletCardActivity.this, "Erro ao converter resposta", Toast.LENGTH_LONG).show();
                }
            }
        },
        new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                error.printStackTrace();
            }
        }){

    @Override
    public Map<String, String> getHeaders() throws AuthFailureError {
        HashMap<String, String> headers = new HashMap<String, String>();
        //headers.put("Content-Type", "application/json");
        headers.put("token", token);
        headers.put("empreendimento", String.valueOf(empreendimento));
        headers.put("coligada", String.valueOf(coligada));
        headers.put("quadra", quadra);
        headers.put("lote",lote);
        return headers;
    }
};

requestQueue.add(request);

文件已成功创建，但未打开

当我从Postman尝试相同的端点时，一切正常，文件保存并打开成功

Answer 1

在将Postman标头与我的代码进行比较后，我发现请求中缺少“Cache-control = no-cache”标头。

添加此标题后，文件已正确下载。

所以改为： 。 。 。 。

 @Override
    public Map<String, String> getHeaders() throws AuthFailureError {
        HashMap<String, String> headers = new HashMap<String, String>();
        headers.put("Cache-Control", "no-cache");
        headers.put("token", token);
        headers.put("empreendimento", String.valueOf(empreendimento));
        headers.put("coligada", String.valueOf(coligada));
        headers.put("quadra", quadra);
        headers.put("lote",lote);
        return headers;
    }

。 。 。 。