Question

Good Evening,

I have been trying to implement a simple Android(tm) application that utilizes Google Places(tm) API to determine local points of interest (such as restaurants and hotels), however I have been having quite a lot of trouble determining how to actually get started.

Resources I have already employed are as follows:

–The Google Places(tm) documentation

–An Android(tm) development blog hosted by Brain Buikema

-The Android(tm) developer documentation on asynchronous tasks

-Various other stackoverflow postings from individuals in similar circumstances

I was simply hoping for some guidance so that anyone in my situation could simply find this post and maybe then be forwarded to some extremely insightful resources.

Further, I feel that using Google searches to find resources is somewhat inefficient, are there other databases out there that programmers frequently utilize of which I am not aware? Any recommended literature?

TL;DR…

-I’m looking for some definitive guides for using the Places API, working with JSON objects and networking on the Android(tm) platform.

-I was hoping to be redirected to some useful sources others have found in the past.

-I have included my Main.java file below simply to provide context – I am not looking for answers 🙂

---

Code for the Main.java class that implements the Places API functionality:

        Button food = (Button) findViewById(R.id.button14);

        food.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) 
        {
            type = "restaurant";

            //Constructs the urlString
            if(useCurr)
                urlString = stringConstructor(myKey, lat, lon, radius, sensor, type);
            else
            {
                //Here, you must update the lat and lon values according to the location input by the user
                urlString = stringConstructor(myKey, lat, lon, radius, sensor, type);
            }



            //DO HTTPS REQUEST HERE
            urlString = "https://maps.googleapis.com/maps/api/place/search/json?location=-33.8670522,151.1957362&radius=500&types=food&name=harbour&sensor=false&key=AIzaSyAp24M3GU9V3kWrrezye8CyUrhtpToUhrs";

            Results res = new Results();

            JSONArray json = res.doInBackground(urlString);

            System.out.println(json);

        }
    });

Code for the Result class that handles the Asynchronous task:

private class Results extends AsyncTask<String, Integer, JSONArray>
{
    protected JSONArray doInBackground(String...params)
    {
        JSONArray output = null;

        try
        {
            try
            {
                url = new URL(params[0]);   
            }
            catch(MalformedURLException e)
            {
                System.out.println("URL formed incorrectly! (" + e + ")");
            }

            output = (JSONArray) url.getContent();
        }
        catch(Exception e)
        {
            System.out.println("Exception: " + e);
        }

        return output;
    }
}    

Currently receiveing an android.os.NetworkOnMainThreatException whenever I click on the “Food” button (described above) in the emulator.

Any advice is greatly welcomed, I am trying to build a really solid foundation on the Android platform.

Answer 1

You are not using AsyncTask in right way. android doc clearly says do’t call AsyncTask methods manually.you are calling doInBackground by creating object of AsyncTask change your code this way:

 btnclicl.setOnClickListener(new View.OnClickListener() {  
                @Override  
                public void onClick(View v) {  
                    Results  dTask = new Results();  
                    dTask.execute(urlString);  
                }  
            });  

    class Results  extends AsyncTask<Integer, Integer, String>{  

            @Override  
        protected void onPostExecute(JSONObject json) {  
            Log.v("json", json);
            super.onPostExecute(json); 
        }  
        @Override  
        protected JSONObject doInBackground(String... params) { 
            JSONObject strtemp=null;            
          HttpClient httpclient = new DefaultHttpClient();
    // Prepare a request object
    HttpGet httpget = new HttpGet(urlString); 
    // Execute the request
    HttpResponse response;
    JSONObject json = new JSONObject();
    try {
        response = httpclient.execute(httpget);

        HttpEntity entity = response.getEntity();

        if (entity != null) {

            // A Simple JSON Response Read
            InputStream instream = entity.getContent();
            String result= convertStreamToString(instream);

            json=new JSONObject(result);

            instream.close();
        }
    } catch (ClientProtocolException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (JSONException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return json;
        }  
}