在android上使用volley下载任何文件（pdf或zip）是否可行？

Question

如何使用android volley下载pdf文件或zip文件。使用字符串、JSON、图像或视频很容易。其他文件呢？

Answer 1

首先，您必须创建自己的定制请求类，如

class InputStreamVolleyRequest extends Request<byte[]> {
private final Response.Listener<byte[]> mListener;
private Map<String, String> mParams;

//create a static map for directly accessing headers
public Map<String, String> responseHeaders ;

public InputStreamVolleyRequest(int method, String mUrl ,Response.Listener<byte[]> listener,
                                Response.ErrorListener errorListener, HashMap<String, String> params) {
  // TODO Auto-generated constructor stub

    super(method, mUrl, errorListener);
     // this request would never use cache.
     setShouldCache(false);
     mListener = listener;
     mParams=params;
}

@Override
protected Map<String, String> getParams()
     throws com.android.volley.AuthFailureError {
  return mParams;
};


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

@Override
protected Response<byte[]> parseNetworkResponse(NetworkResponse response) {

    //Initialise local responseHeaders map with response headers received
    responseHeaders = response.headers;

    //Pass the response data here
    return Response.success( response.data, HttpHeaderParser.parseCacheHeaders(response));
}
}

现在只需通过我们的定制类发送请求即可。方法获取和要从中加载文件的url。

String mUrl= <YOUR_URL>;
InputStreamVolleyRequest request = new     InputStreamVolleyRequest(Request.Method.GET, mUrl,
    new Response.Listener<byte[]>() { 
         @Override 
         public void onResponse(byte[] response) { 
       // TODO handle the response 
        try { 
        if (response!=null) {

          FileOutputStream outputStream;
          String name=<FILE_NAME_WITH_EXTENSION e.g reference.txt>;
            outputStream = openFileOutput(name, Context.MODE_PRIVATE);
            outputStream.write(response);
            outputStream.close();
            Toast.makeText(this, "Download complete.", Toast.LENGTH_LONG).show();
        }
    } catch (Exception e) {
        // TODO Auto-generated catch block
        Log.d("KEY_ERROR", "UNABLE TO DOWNLOAD FILE");
        e.printStackTrace();
    }
  }
} ,new Response.ErrorListener() {

@Override
public void onErrorResponse(VolleyError error) {
// TODO handle the error
error.printStackTrace();
  }
}, null);
      RequestQueue mRequestQueue = Volley.newRequestQueue(getApplicationContext(), new HurlStack());
      mRequestQueue.add(request);