How to get to a JSON object in this output using Spring for Android

Question

I have a url: https://api.spreaker.com/v2/users/7725967/episodes?limit=1. I am trying to get to the variables in the JSON results.

Using Spring for Android, I have the following code:

import android.os.AsyncTask;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.NavigationView;
import android.support.design.widget.Snackbar;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;

import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.client.RestTemplate;

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);
    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();

        if (id == R.id.nav_camera) {
            // Handle the camera action


        } else if (id == R.id.nav_gallery) {

        } else if (id == R.id.nav_slideshow) {

        } else if (id == R.id.nav_manage) {

        } else if (id == R.id.nav_share) {

        } else if (id == R.id.nav_send) {

        }

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

    @Override
    protected void onStart() {
        super.onStart();
        new HttpRequestTask().execute();
    }

    private class HttpRequestTask extends AsyncTask<Void, Void, RadioInfo> {
        @Override
        protected RadioInfo doInBackground(Void... params) {
            try {
                final String url = "https://api.spreaker.com/v2/users/7725967/episodes?limit=1";
                RestTemplate restTemplate = new RestTemplate();
                restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
                return restTemplate.getForObject(url, RadioInfo.class);
            } catch (Exception e) {
                Log.e("MainActivity", e.getMessage(), e);
            }

            return null;
        }


        @Override
        protected void onPostExecute(RadioInfo radioInfo) {
            TextView radioInfoIdText = (TextView) findViewById(R.id.songName);
            TextView radioInfoTypeText = (TextView) findViewById(R.id.radioInfo);
            TextView radioInfoIdRadio = (TextView) findViewById(R.id.showInfo);
            radioInfoIdText.setText(radioInfo.getTitle());
            radioInfoTypeText.setText(radioInfo.getType());
            radioInfoIdRadio.setText(radioInfo.getId());


        }
    }
}

My JSON output is as follows:

{
  "response": {
    "items": [
      {
        "episode_id": 9019035,
        "type": "RECORDED",
        "title": "Abu Mohamed",
        "duration": 5046750,
        "show_id": 1392547,
        "author_id": 7725967,
        "site_url": "https://www.spreaker.com/episode/9019035",
        "image_url": "https://d1bm3dmew779uf.cloudfront.net/large/618b5806c9854bc8379ded0c27cc0694.jpg",
        "image_original_url": "https://d3wo5wojvuv7l.cloudfront.net/images.spreaker.com/original/618b5806c9854bc8379ded0c27cc0694.jpg",
        "published_at": "2016-07-20 01:13:37",
        "download_enabled": true,
        "waveform_url": "https://d3770qakewhkht.cloudfront.net/episode_9019035.gz.json?v=a7ZcQU"
      }
    ],
    "next_url": "https://api.spreaker.com/v2/users/7725967/episodes?filter=listenable&last_id=9019035&limit=1"
  }
}

Here is my issue: Android studio throws a null error somewhere in these lines:

public class HttpRequestTask extends AsyncTask<Void, Void, RadioInfo> {
    @Override
    protected RadioInfo doInBackground(Void... params) {
        try {
            String url = "https://api.spreaker.com/v2/users/7725967/episodes?limit=1";
            RestTemplate restTemplate = new RestTemplate();
            restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
            String result = String.valueOf(restTemplate.getForObject(url, RadioInfo.class, "Android"));
            return restTemplate.getForObject(url, RadioInfo.class);
        } catch (Exception e) {
            Log.e("MainActivity", e.getMessage(), e);
        }

        return null;
    }


    @Override
    protected void onPostExecute(RadioInfo radioInfo) {
        TextView radioInfoIdText = (TextView) findViewById(R.id.songName);
        TextView radioInfoTypeText = (TextView) findViewById(R.id.type);
        TextView radioInfoIdRadio = (TextView) findViewById(R.id.showInfo);
        radioInfoIdText.setText(radioInfo.getTitle());
        radioInfoTypeText.setText(radioInfo.getType());
        radioInfoIdRadio.setText(radioInfo.getId());


    }
}

I do not understand how it is a null I am returning. I think it's because of the JSON format, but I am not sure. I must be mapping it correctly as Jackson should handle this just fine.

How can I implement this correctly?

Here is my Radio class:

public class RadioInfo {

    private String episode_id;
    private String type;
    private String title;

    public String getId() {
        return this.episode_id;
    }

    public String getType() {
        return this.type;
    }

    public String getTitle() {
        return this.title;
    }
}

Update

The permissions error was due to me not being careful where I placed the internet permissions in the Android manifest XMl file.

So my original question is still in play, with a new stack trace on the JSON parsing and null object error:

07-23 19:45:47.613 14016-14084/software.blackstone.masjidtawheedmobileradio E/MainActivity: Could not read JSON: Unrecognized field "response" (class software.blackstone.masjidtawheedmobileradio.RadioInfo), not marked as ignorable (2 known properties: "title", "type"])
                                                                                                at [Source: buffer(com.android.okhttp.okio.GzipSource@dbb91a).inputStream(); line: 1, column: 14] (through reference chain: software.blackstone.masjidtawheedmobileradio.RadioInfo["response"]); nested exception is com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "response" (class software.blackstone.masjidtawheedmobileradio.RadioInfo), not marked as ignorable (2 known properties: "title", "type"])
                                                                                                at [Source: buffer(com.android.okhttp.okio.GzipSource@dbb91a).inputStream(); line: 1, column: 14] (through reference chain: software.blackstone.masjidtawheedmobileradio.RadioInfo["response"])
                                                                                            org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: Unrecognized field "response" (class software.blackstone.masjidtawheedmobileradio.RadioInfo), not marked as ignorable (2 known properties: "title", "type"])
                                                                                                at [Source: buffer(com.android.okhttp.okio.GzipSource@dbb91a).inputStream(); line: 1, column: 14] (through reference chain: software.blackstone.masjidtawheedmobileradio.RadioInfo["response"]); nested exception is com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "response" (class software.blackstone.masjidtawheedmobileradio.RadioInfo), not marked as ignorable (2 known properties: "title", "type"])
                                                                                                at [Source: buffer(com.android.okhttp.okio.GzipSource@dbb91a).inputStream(); line: 1, column: 14] (through reference chain: software.blackstone.masjidtawheedmobileradio.RadioInfo["response"])
                                                                                                at org.springframework.http.converter.json.MappingJackson2HttpMessageConverter.readInternal(MappingJackson2HttpMessageConverter.java:126)
                                                                                                at org.springframework.http.converter.AbstractHttpMessageConverter.read(AbstractHttpMessageConverter.java:147)
                                                                                                at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:76)
                                                                                                at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:484)
                                                                                                at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:439)
                                                                                                at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:237)
                                                                                                at software.blackstone.masjidtawheedmobileradio.MainActivity$HttpRequestTask.doInBackground(MainActivity.java:133)
                                                                                                at software.blackstone.masjidtawheedmobileradio.MainActivity$HttpRequestTask.doInBackground(MainActivity.java:126)
                                                                                                at android.os.AsyncTask$2.call(AsyncTask.java:295)
                                                                                                at java.util.concurrent.FutureTask.run(FutureTask.java:237)
                                                                                                at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)
                                                                                                at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
                                                                                                at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
                                                                                                at java.lang.Thread.run(Thread.java:818)
                                                                                             Caused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "response" (class software.blackstone.masjidtawheedmobileradio.RadioInfo), not marked as ignorable (2 known properties: "title", "type"])
                                                                                                at [Source: buffer(com.android.okhttp.okio.GzipSource@dbb91a).inputStream(); line: 1, column: 14] (through reference chain: software.blackstone.masjidtawheedmobileradio.RadioInfo["response"])
                                                                                                at com.fasterxml.jackson.databind.DeserializationContext.reportUnknownProperty(DeserializationContext.java:671)
                                                                                                at com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:771)
                                                                                                at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1297)
                                                                                                at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownVanilla(BeanDeserializerBase.java:1275)
                                                                                                at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:247)
                                                                                                at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:118)
                                                                                                at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose
07-23 19:45:47.674 14016-14016/software.blackstone.masjidtawheedmobileradio D/AndroidRuntime: Shutting down VM
                                                                                              
                                                                                              
                                                                                              --------- beginning of crash
07-23 19:45:47.686 14016-14016/software.blackstone.masjidtawheedmobileradio E/AndroidRuntime: FATAL EXCEPTION: main
                                                                                              Process: software.blackstone.masjidtawheedmobileradio, PID: 14016
                                                                                              java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String software.blackstone.masjidtawheedmobileradio.RadioInfo.getTitle()' on a null object reference
                                                                                                  at software.blackstone.masjidtawheedmobileradio.MainActivity$HttpRequestTask.onPostExecute(MainActivity.java:148)
                                                                                                  at software.blackstone.masjidtawheedmobileradio.MainActivity$HttpRequestTask.onPostExecute(MainActivity.java:126)
                                                                                                  at android.os.AsyncTask.finish(AsyncTask.java:651)
                                                                                                  at android.os.AsyncTask.-wrap1(AsyncTask.java)
                                                                                                  at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:668)
                                                                                                  at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                                                  at android.os.Looper.loop(Looper.java:148)
                                                                                                  at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                                                                  at java.lang.reflect.Method.invoke(Native Method)
                                                                                                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                                                                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
07-23 19:50:48.015 14016-14016/software.blackstone.masjidtawheedmobileradio I/Process: Sending signal. PID: 14016 SIG: 9

Can you post the stacktrace please? Also post your RadioInfo class — ucsunil, Jul 20 '16 at 23:58

score 1 · Accepted Answer · edited May 23 '17 at 12:02

1

According to your stack trace, you need to request permission to use internet. Try adding

<uses-permission android:name="android.permission.INTERNET" />

to your manifest, and after that, you also have to request the permission at runtime if your targeting API level 23 or after, look here for more info: What permission do I need to access Internet from an android application? https://developer.android.com/training/permissions/requesting.html

For the requesting permission at runtime, you can try adding the following to your onCreate in your MainActivity, for example

// Check permission for INTERNET
if (ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.INTERNET) != 
        PackageManager.PERMISSION_GRANTED) {
    // Request Permissions Now
    ActivityCompat.requestPermissions(getActivity(),
            new String[]{Manifest.permission.INTERNET},
            MainActivity.REQUEST_INTERNET);
}

you can also look here: http://inducesmile.com/android/android-6-marshmallow-runtime-permissions-request-example/

edited May 23 '17 at 12:02

Community

1
1

answered Jul 21 '16 at 00:23

Jon

2,907
1
12
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I have tried this proposed solution seven ways to nowhere and I still have the same error.... – ironmantis7x Jul 22 '16 at 02:36
Is it still giving you the `java.lang.SecurityException: Permission denied (missing INTERNET permission?)` error message? – Jon Jul 22 '16 at 12:58
--nyes it is and I have internet permissions in the AndroidManefest xml file. – ironmantis7x Jul 23 '16 at 13:48
yes it instill giving this error and I have internet permissions in the AndroidManifest.xml file – ironmantis7x Jul 23 '16 at 22:07
And you're also checking for the permission at runtime too? – Jon Jul 23 '16 at 22:23
that's where I am confused.... I tried what was in your posted suggestion and it does not work ... – ironmantis7x Jul 23 '16 at 22:25
when I use the code solution above you posted for checking at run time, I get this error: Error:(54, 48) error: cannot find symbol method getActivity() Error:(57, 47) error: cannot find symbol method getActivity() Error:(59, 33) error: cannot find symbol variable REQUEST_INTERNET – ironmantis7x Jul 23 '16 at 22:32
lol!! silly me!! I got past the internet permissions thing by placing permissions internet in the correct place in the AndroidManefest (bonehead error!! -- and I have plenty of android apps where I use internet permissions all the time and never made this mistake before). Now I have a jackson json parse error ... – ironmantis7x Jul 23 '16 at 23:17

How to get to a JSON object in this output using Spring for Android

Update

1 Answers1