android parse internal storage output

Question

i want to parse my internal Storage output, but i get always a NullPointerException

Here is my errorlog:

08-20 18:32:49.089: W/System.err(1149): java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
08-20 18:32:49.089: W/System.err(1149):     at android.os.Handler.<init>(Handler.java:197)
08-20 18:32:49.089: W/System.err(1149):     at android.os.Handler.<init>(Handler.java:111)
08-20 18:32:49.089: W/System.err(1149):     at android.app.Activity.<init>(Activity.java:759)
08-20 18:32:49.089: W/System.err(1149):     at android.support.v4.app.FragmentActivity.<init>(FragmentActivity.java:70)
08-20 18:32:49.089: W/System.err(1149):     at de.everhome.cloudbox.DeviceActivity.<init>(DeviceActivity.java:54)
08-20 18:32:49.089: W/System.err(1149):     at de.everhome.parser.SceneParserIS.downloadUrl(SceneParserIS.java:77)
08-20 18:32:49.089: W/System.err(1149):     at de.everhome.parser.SceneParserIS.parse(SceneParserIS.java:109)
08-20 18:32:49.089: W/System.err(1149):     at de.everhome.cloudbox.Fragment2$DoRssFeedTask.doInBackground(Fragment2.java:125)
08-20 18:32:49.089: W/System.err(1149):     at de.everhome.cloudbox.Fragment2$DoRssFeedTask.doInBackground(Fragment2.java:1)
08-20 18:32:49.089: W/System.err(1149):     at android.os.AsyncTask$2.call(AsyncTask.java:287)
08-20 18:32:49.089: W/System.err(1149):     at java.util.concurrent.FutureTask.run(FutureTask.java:234)
08-20 18:32:49.089: W/System.err(1149):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
08-20 18:32:49.089: W/System.err(1149):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
08-20 18:32:49.089: W/System.err(1149):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
08-20 18:32:49.089: W/System.err(1149):     at java.lang.Thread.run(Thread.java:841)

and here is my javaclass for the parsing:

   package de.everhome.parser;

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserFactory;

import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import de.everhome.cloudbox.DeviceActivity;
import de.everhome.model.SceneReader;

public class SceneParserIS {
    private XmlPullParserFactory factory;
    private XmlPullParser parser;

    private List<SceneReader> SceneList;
    private SceneReader rssFeed;

  //  private String urlString;
    private String total;
    private String tagName;

    private String title;
    private String link;
    private String description;
    private String category;
    private String pubDate;
    private String guid;
    private String feedburner;
    public static final String DEVICE = "scene";
    public static final String DEVICES = "scenes";

    public static final String DEVICENAME= "scenename";
    public static final String TEXT1 ="text1";
    public static final String DEVICEID = "sceneid";
    public static final String FEEDBURNERORIGLINK = "feedburner:origLink";
    private InputStream urlStream;
    private String urlString;

    public SceneParserIS(String urlString) {
        this.urlString = urlString;
    }
   /* public SceneParserIS(Context ctx)throws IOException {
        String filename = "cloudbox";
        FileInputStream inputStream = ctx.openFileInput(filename);
         BufferedReader r = new BufferedReader(new InputStreamReader(inputStream));
         StringBuilder total = new StringBuilder();
         String line;
         while ((line = r.readLine()) != null) {
             total.append(line);
         }
         r.close();
         inputStream.close();
         Log.d("File", "File contents: " + total);
         String totalstring = total.toString();
         InputStream totalinput = new ByteArrayInputStream(totalstring.getBytes("UTF-8"));

         }*/
    protected Context getContext() {
        Context context = null;
        return context;

    }

    public InputStream downloadUrl(String urlString) throws IOException {

        DeviceActivity bckp = new DeviceActivity();  // send parameters if your constructor takes them

        URL url = new URL(urlString);
        Context ActivityContext = this.getContext();
        /* URL url = new URL(urlString);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");
        conn.setDoInput(true);
        conn.connect();
        InputStream stream = conn.getInputStream();*/
        String filename = "cloudbox";
        FileInputStream inputStream =  bckp.openFileInput(filename);
         BufferedReader r = new BufferedReader(new InputStreamReader(inputStream));
         StringBuilder total = new StringBuilder();
         String line;
         while ((line = r.readLine()) != null) {
             total.append(line);
         }
         r.close();
         inputStream.close();
         Log.d("File", "File contents: " + total);
         String totalstring = total.toString();
         InputStream totalinput = new ByteArrayInputStream(totalstring.getBytes("UTF-8"));
        return totalinput;
    }

    public List<SceneReader> parse() { 
        try {
            @SuppressWarnings("unused")
            int count = 0;
            factory = XmlPullParserFactory.newInstance();
            parser = factory.newPullParser();
            urlStream = downloadUrl(urlString);
         //   urlStream = SceneParserIS(Context ctx);
            parser.setInput(urlStream, null);
            int eventType = parser.getEventType();
            boolean done = false;
            rssFeed = new SceneReader();
            SceneList = new ArrayList<SceneReader>();
            while (eventType != XmlPullParser.END_DOCUMENT && !done) {
                tagName = parser.getName();

                switch (eventType) {
                    case XmlPullParser.START_DOCUMENT:
                        break;
                    case XmlPullParser.START_TAG:
                        if (tagName.equals(DEVICE)) {
                            rssFeed = new SceneReader();
                        }
                        if (tagName.equals(DEVICENAME)) {
                            title = parser.nextText().toString();
                        }
                        if (tagName.equals(TEXT1)) {
                            category = parser.nextText().toString();
                        }
                        if (tagName.equals(DEVICEID)) {
                            guid = parser.nextText().toString();
                        }
                        if (tagName.equals(FEEDBURNERORIGLINK)) {
                            feedburner = parser.nextText().toString();
                        }
                        break;
                    case XmlPullParser.END_TAG:
                        if (tagName.equals(DEVICES)) {
                            done = true;
                        } else if (tagName.equals(DEVICE)) {

                            rssFeed = new SceneReader(title, link, description, category, pubDate,
                                    guid,
                                    feedburner);
                            SceneList.add(rssFeed);
                        }
                        break;
                }
                eventType = parser.next();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        Log.d("App", "parser beendet");
        return SceneList;

    }
}

and the class with the asynctask:

package de.everhome.cloudbox;

import de.everhome.model.DeviceReader;
import de.everhome.model.SceneReader;
import de.everhome.parser.SceneParser;
import de.everhome.parser.SceneParserIS;
import de.everhome.R;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

/*public class Fragment1 extends Fragment{

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
        return inflater.inflate(R.layout.rss_feed_view, null);
    }
}*/
import java.util.ArrayList;
import java.util.List;
import com.astuetz.viewpager.extensions.PagerSlidingTabStrip;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Handler;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class Fragment2 extends Fragment implements OnItemClickListener {

    private ListView mRssListView;
    private SceneParserIS mNewsFeeder;
    private List<SceneReader> mRssFeedList;
    private RssAdapter mRssAdap;
    private static final String TOPSTORIES =
            "some url";

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        View V = inflater.inflate(R.layout.rss_feed_view, container, false);
        mRssListView = (ListView) V.findViewById(R.id.rss_list_view);
        mRssFeedList = new ArrayList<SceneReader>();
        new DoRssFeedTask().execute(TOPSTORIES);
        mRssListView.setOnItemClickListener(this);
        return V;
    }

    private class RssAdapter extends ArrayAdapter<SceneReader> {
        private List<SceneReader> rssFeedLst;

        public RssAdapter(Context context, int textViewResourceId, List<SceneReader> rssFeedLst) {
            super(context, textViewResourceId, rssFeedLst);
            this.rssFeedLst = rssFeedLst;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            View view = convertView;
            RssHolder rssHolder = null;
            if (convertView == null) {
                Context context = getContext();
                view = View.inflate(context, R.layout.scene_item, null);
                rssHolder = new RssHolder();
                rssHolder.rssTitleView = (TextView) view.findViewById(R.id.rss_title_view);
                rssHolder.rssbuttonpositiv = (Button) view.findViewById(R.id.on);
                view.setTag(rssHolder);
            } else {
                rssHolder = (RssHolder) view.getTag();
            }
            final SceneReader rssFeed = rssFeedLst.get(position);
            rssHolder.rssTitleView.setText(rssFeed.getName());
            rssHolder.rssbuttonpositiv.setText(rssFeed.getpositiv());
            rssHolder.rssbuttonpositiv.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {
                    String[] url={"http://everhome.de/api/applive/","8ef43502ad3dc04f87b4a48b993878c0",rssFeed.getdeviceid()};
                    //String[] url={"http://everhome.de/api/applive/","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",rssFeed.getdeviceid(),rssFeed.getaction1()};
                    Context context = getContext();
                    new run(context).execute(url);
                    CharSequence text = "Führe Szene durch: " + rssFeed.getdeviceid();
                    int duration = Toast.LENGTH_SHORT;

                    Toast toast = Toast.makeText(context, text, duration);
                    toast.show();
                    Log.d("App", "test");
                }});
            return view;
        }
    }

    static class RssHolder {
        public TextView rssTitleView;
        public Button rssbuttonpositiv;
        public Button rssbuttonnegativ;
    }

    public class DoRssFeedTask extends AsyncTask<String, Void, List<SceneReader>> {
        ProgressDialog prog;
        String jsonStr = null;
        Handler innerHandler;

        @Override
        protected void onPreExecute() {
            //Context context = getContext();
            prog = new ProgressDialog(getActivity());
            prog.setMessage("Loading....");
            prog.show();
        }

        @Override
        protected List<SceneReader> doInBackground(String... params) {
            for (String urlVal : params) {
                mNewsFeeder = new SceneParserIS(urlVal);
            }
            mRssFeedList = mNewsFeeder.parse();
            return mRssFeedList;
        }

        @Override
        protected void onPostExecute(List<SceneReader> result) {
            prog.dismiss();
            getActivity().runOnUiThread(new Runnable() {

                @Override
                public void run() {
                    mRssAdap = new RssAdapter(getActivity(), R.layout.device_item,
                            mRssFeedList);
                    int count = mRssAdap.getCount();
                    if (count != 0 && mRssAdap != null) {
                        mRssListView.setAdapter(mRssAdap);
                    }
                }
            });
        }


            @Override
            protected void onProgressUpdate(Void... values) {
                // TODO Auto-generated method stub
                super.onProgressUpdate(values);
                prog.dismiss();
                CharSequence text = "Keine Verbindung zum Server!";
                int duration = Toast.LENGTH_SHORT;

                Toast toast = Toast.makeText(getActivity(), text, duration);
                toast.show();
        }
    }

    @Override
    public void onItemClick(AdapterView<?> adapterView, View v, int position, long id) {
    }



    public class MyPagerAdapter extends FragmentPagerAdapter {

        private final String[] TITLES = { "Geräte", "Szenen" };

        public MyPagerAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public CharSequence getPageTitle(int position) {
            return TITLES[position];
        }
        @Override  
        public Fragment getItem(int position) {  
            Fragment fragment = new Fragment();  
            switch (position) {  
            case 0:  
                return fragment = new Fragment1();  
            case 1:  
                return fragment = new Fragment1();
            default:  
                break;  
            }  
            return fragment;  
    }

        @Override
        public int getCount() {
            return TITLES.length;
        }
    }  
}

i think its because the Context Context; on Context.openFileInput(filename).

Answer 1

On line 38 you declare:

Context Context;

but never set this variable anywhere, so it's default declaration will be null, so on line 62 when you call

FileInputStream inputStream = Context.openFileInput(filename);

The value of Context is null, hence the NullPointerException. You will need to get a value for the "Context" variable, maybe pass it into the constructor from an activity. I would also recommend renaming that variable to start with a lower case character. That would eliminate confusion here, and it wouldn't look like you were calling a static method on the Context class.