Error with my Android Application httpGet

Question

Basically I'm getting a strange issue with my Android application, it's supposed to grab a JSON Array and print out some values, the class looks like this:

ShowComedianActivity.class

package com.example.connecttest;

public class ShowComedianActivity extends Activity{

    TextView name;
    TextView add;
    TextView email;
    TextView tel;

    String id;

    // Progress Dialog
    private ProgressDialog pDialog;

    //JSON Parser class
    JSONParser jsonParser = new JSONParser();

    // Single Comedian url
    private static final String url_comedian_details = "http://86.9.71.17/connect/get_comedian_details.php";


    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_COMEDIAN = "comedian";
    private static final String TAG_ID = "id";
    private static final String TAG_NAME = "name";
    private static final String TAG_ADDRESS = "address";
    private static final String TAG_EMAIL = "email";
    private static final String TAG_TEL = "tel";

    public void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.show_comedian);

        // Getting Comedian Details from intent
        Intent i = getIntent();

        // Getting id from intent
        id = i.getStringExtra(TAG_ID);

        new GetComedianDetails().execute();

    }

    class GetComedianDetails extends AsyncTask<String, String, String>{

        protected void onPreExecute(){
            super.onPreExecute();
            pDialog = new ProgressDialog(ShowComedianActivity.this);
            pDialog.setMessage("Fetching Comedian details. Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }

        @Override
        protected String doInBackground(String... params) {

            runOnUiThread(new Runnable(){
                public void run(){
                    int success;
                    try{
                        //Building parameters
                        List<NameValuePair> params = new ArrayList<NameValuePair>();
                        params.add(new BasicNameValuePair("id",id));

                        // Getting comedian details via HTTP request
                        // Uses a GET request

                        JSONObject json = jsonParser.makeHttpRequest(url_comedian_details, "GET", params);
                        // Check Log for json response
                        Log.d("Single Comedian details", json.toString());

                        //JSON Success tag
                        success = json.getInt(TAG_SUCCESS);
                        if(success == 1){
                            // Succesfully received product details
                            JSONArray comedianObj = json.getJSONArray(TAG_COMEDIAN); //JSON Array

                            // get first comedian object from JSON Array
                            JSONObject comedian = comedianObj.getJSONObject(0);

                            // comedian with id found
                            name = (TextView) findViewById(R.id.name);
                            add = (TextView) findViewById(R.id.add);
                            email = (TextView) findViewById(R.id.email);
                            tel = (TextView) findViewById(R.id.tel);

                            // Set text to details
                            name.setText(comedian.getString(TAG_NAME));
                            add.setText(comedian.getString(TAG_ADDRESS));
                            email.setText(comedian.getString(TAG_EMAIL));
                            tel.setText(comedian.getString(TAG_TEL));

                        }

                    } catch (JSONException e){
                        e.printStackTrace();
                    }
                }
            });

            return null;
        }

    }


}

And my JSON Parser class looks like:

package com.example.connecttest;

public class JSONParser {

    static InputStream is = null;
    static JSONObject jObj = null;
    static String json = "";

    // constructor
    public JSONParser() {

    }

    // function get json from url
    // by making HTTP POST or GET method
    public JSONObject makeHttpRequest(String url, String method,
            List<NameValuePair> params) {

        // Making HTTP request
        try {

            // check for request method
            if(method == "POST"){
                // request method is POST
                // defaultHttpClient
                DefaultHttpClient httpClient = new DefaultHttpClient();
                HttpPost httpPost = new HttpPost(url);
                httpPost.setEntity(new UrlEncodedFormEntity(params));

                HttpResponse httpResponse = httpClient.execute(httpPost);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();

            }else if(method == "GET"){
                // request method is GET
                DefaultHttpClient httpClient = new DefaultHttpClient();
                String paramString = URLEncodedUtils.format(params, "utf-8");
                url += "?" + paramString;
                HttpGet httpGet = new HttpGet(url);

                HttpResponse httpResponse = httpClient.execute(httpGet);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();
            }           

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            is.close();
            json = sb.toString();
        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }

        // try parse the string to a JSON object
        try {
            jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON String
        return jObj;

    }
}

Now when I run a debug it's querying the correct address with ?id=1 on the end of the URL, and when I navigate to that url I get the following JSON Array:

{"success":1,"comedian":[{"id":"1","name":"Michael Coombes","address":"5 Trevethenick Road","email":"mc6415@gmail.com","tel":"xxxxxxxxxxxx"}]}

However my app just crashes, the log-cat report looks like this:

03-22 02:05:02.140: E/Trace(3776): error opening trace file: No such file or directory (2)
03-22 02:05:04.590: E/AndroidRuntime(3776): FATAL EXCEPTION: main
03-22 02:05:04.590: E/AndroidRuntime(3776): android.os.NetworkOnMainThreadException
03-22 02:05:04.590: E/AndroidRuntime(3776):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at libcore.io.IoBridge.connect(IoBridge.java:112)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at java.net.Socket.connect(Socket.java:842)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at com.example.connecttest.JSONParser.makeHttpRequest(JSONParser.java:62)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at com.example.connecttest.ShowComedianActivity$GetComedianDetails$1.run(ShowComedianActivity.java:89)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at android.os.Handler.handleCallback(Handler.java:615)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at android.os.Handler.dispatchMessage(Handler.java:92)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at android.os.Looper.loop(Looper.java:137)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at android.app.ActivityThread.main(ActivityThread.java:4745)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at java.lang.reflect.Method.invokeNative(Native Method)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at java.lang.reflect.Method.invoke(Method.java:511)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
03-22 02:05:04.590: E/AndroidRuntime(3776):     at dalvik.system.NativeStart.main(Native Method)

From this I'm guessing the error is in the jsonParser.makeHttpRequest however I can't for the life of me figure out what's going wrong and was hoping someone brighter than I could illuminate me.

Answer 1

First, remember to actually read the stack trace, the answer is in the first line. When running your App in strict mode (I think the newer versions of Android do by default), Android will throw NetworkOnMainThreadException if you try to do any network calls on the UI thread, because you DO NOT want to block the UI thread.

E/AndroidRuntime(3776): android.os.NetworkOnMainThreadException
E/AndroidRuntime(3776):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)

Looking down the trace here's you code that is causing the issue:

E/AndroidRuntime(3776):     at com.example.connecttest.JSONParser.makeHttpRequest(JSONParser.java:62)
E/AndroidRuntime(3776):     at com.example.connecttest.ShowComedianActivity$GetComedianDetails$1.run(ShowComedianActivity.java:89)

Here's the actual line:

JSONObject json = jsonParser.makeHttpRequest(url_comedian_details, "GET", params);

Upon inspection, you are actually running your network call in doInBackground, which runs off the main thread, which is where you want to do network calls (since you can block that thread all you want). However, you are running your network call inside runOnUiThread, so you are then turning back around and running your network call on the UI thread, and then Android throws NetworkOnMainThreadException.

I suggest you remove the runOnUiThread piece, as that is a bad practice, and pass in your request parameters to your AsyncTask.

More info on the error - How to fix android.os.NetworkOnMainThreadException?.

Answer 2

You are getting android.os.NetworkOnMainThreadException because you are "attempts to perform a networking operation on its main thread." AsyncTask is a Thread ,so remove:

 runOnUiThread(new Runnable(){
                public void run(){

and the closing brackets.