Java Android AsyncHttpClient将byte [] responseBody转换为InputStream

Question

I want to create a methos which return a InputStream I did this :

 public static InputStream sendGetDataRequest(Context context,
                                                 String version, String power, String lon, String lat, String radius)  throws MalformedURLException, ConnectTimeoutException, IOException

    {
        AsyncHttpClient client = new AsyncHttpClient();
        String url = Util.getServerUrl(context) + "/GetData";
//        ContentValues values=new ContentValues();
        RequestParams values = new RequestParams();

        values.put("token", String.valueOf(E_Gps.TOKEN));
        values.put("xml", login_xml);
        StringEntity entity = null;
        try {
            entity = new StringEntity(values.toString());
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        entity.setContentType(new BasicHeader("Content-Type","application/xml"));
        final InputStream[] is = new InputStream[1];
        final InputStream inputStream;
        client.post(context,url,values , new AsyncHttpResponseHandler(Looper.getMainLooper()) {

            @Override
            public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {
                Log.e("success_noti", new String(responseBody) + "");
                is[0] = new ByteArrayInputStream(responseBody);
                Log.e("Status " , statusCode + " ");
                Log.e("is" , convertStreamToString(is[0]));
            }

            @Override
            public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable error) {
                Log.e("success_noti", new String(responseBody) + "");
                Log.e("Status " , statusCode + " ");


}
    });
return is[0];
}

And I have probleme when I return is[0] is a null but when I log in onSuccess :

Log.e("is" , convertStreamToString(is[0]));

is not null why I have null object is[0] ?

Answer 1

Because client.post is an asynchronous call while return is[0] is a synchronous. This means that is[0] is null as long as the async call is not done yet. One way to solve is by making sendGetDataRequest return void and instead accepts a callback eg

public static void sendGetDataRequest(final YourCallback callback, ...)

Create a new Interface named YourCallback

public interface YourCallback{
  void onSuccess(String string);
  void failure();
}

And use that Callback inside the async method

 client.post(context,url,values , new AsyncHttpResponseHandler(Looper.getMainLooper()) {

            @Override
            public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {
                callback.onSuccess(convertStreamToString(is[0]));
            }

            @Override
            public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable error) {
              callback.onFailure(); 
            }
}

Finally you call your static method like this

sendGetDataRequest(new YourCallback(){/* Override the methods */}, ...);

By the way you could also use AsyncTask from the android package which does everything above. It's personal preference.