Android Open Source - scanvine-android Story List Fragment

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License

The source code is released under:
Copyright (c) 2013 Jonathan Evans (http://www.rezendi.com) Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Softw...
If you think the Android project scanvine-android listed in this page is inappropriate, such as containing malicious code/tools or violating the copyright, please email info at java2s dot com, thanks.
Java Source Code

package com.scanvine.android.ui;
/* ww  w.j  av  a2  s. c  o  m*/
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONObject;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;

import com.scanvine.android.R;
import com.scanvine.android.model.Source;
import com.scanvine.android.model.Story;
import com.scanvine.android.util.Util;

/**
 * A list fragment representing a list of Stories. This fragment also supports
 * tablet devices by allowing list items to be given an 'activated' state upon
 * selection. This helps indicate which item is currently being viewed in a
 * {@link StoryDetailFragment}.
 * <p>
 * Activities containing this fragment MUST implement the {@link Callbacks} interface.
 */
public class StoryListFragment extends ListFragment {

  private static final String STATE_ACTIVATED_POSITION = "activated_position"; //only used on tables
  private int mActivatedPosition = ListView.INVALID_POSITION; //only used on tables
  private Callbacks mCallbacks = sDummyCallbacks;
  private ArrayList<Story> stories = new ArrayList<Story>();

  public interface Callbacks {
    public void onItemSelected(String json);
      public void showProgress(Boolean progress);
  }

  // A dummy implementation for use when not attached to an activity.
  private static Callbacks sDummyCallbacks = new Callbacks() {
    @Override
    public void onItemSelected(String json) {}
      public void showProgress(Boolean progress) {}
  };

  // Mandatory empty constructor for the fragment manager to instantiate the fragment.
  public StoryListFragment() { }

  @Override
  public void onAttach(Activity activity) {
    super.onAttach(activity);
    if (!(activity instanceof Callbacks))
      throw new IllegalStateException("Activity must implement fragment's callbacks.");
    mCallbacks = (Callbacks) activity;
  }

  @Override
  public void onDetach() {
    super.onDetach();
    mCallbacks = sDummyCallbacks;
  }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        ListView lv = (ListView) inflater.inflate(R.layout.fragment_story_list, container, false);
        lv.setDivider(null);
        lv.setDividerHeight(0);
    return lv;

    }
    
    @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    String slug = null;
    if (getActivity().getIntent().getExtras()!=null) {  
      String json = getActivity().getIntent().getExtras().getString(StoryListActivity.SOURCE);
      Source source = Source.GetSourceFor(json);
      slug = source.getSlug();
    }
    refreshList(null, null, slug);
  }
  
    @Override
  public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    if (savedInstanceState != null && savedInstanceState.containsKey(STATE_ACTIVATED_POSITION))
      setActivatedPosition(savedInstanceState.getInt(STATE_ACTIVATED_POSITION));
  }

  @Override
  public void onListItemClick(ListView listView, View view, int position,
      long id) {
    super.onListItemClick(listView, view, position, id);
    mCallbacks.onItemSelected(stories.get(position).getJSON());
  }

  @Override
  public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    if (mActivatedPosition != ListView.INVALID_POSITION) {
      // Serialize and persist the activated item position.
      outState.putInt(STATE_ACTIVATED_POSITION, mActivatedPosition);
    }
  }

  private void renderStories() {
    Activity activity = getActivity();
    if (activity!=null)
      setListAdapter(new StoryArrayAdapter(activity, this, R.id.story_list, stories));
  }
  
  public void showDownloads() {
    new ListDownloadsTask().execute();
  }

  public void selectItem(int n) {
    String json = stories.get(n).getJSON();
    mCallbacks.onItemSelected(json);
  }
  
  public void refreshList(String time, String section, String source) {
    refreshList(time, section, source, false);
  }

  public void refreshListFromCache(String time, String section, String source) {
    refreshList(time, section, source, true);
  }

  private void refreshList(String time, String section, String source, boolean cached) {
    if (source!=null && "Firehose".equalsIgnoreCase(time))
      time = null;
    if (source==null && "Latest".equalsIgnoreCase(time))
      time = null;
    if (time==null && section==null && source==null)
      time = "Latest";
    new StoryFetchTask().execute(time, section, source, cached ? "cached" : null);
  }

  public void setActivateOnItemClick(boolean activateOnItemClick) {
    getListView().setChoiceMode(activateOnItemClick ? ListView.CHOICE_MODE_SINGLE : ListView.CHOICE_MODE_NONE);
  }

  private void setActivatedPosition(int position) {
    if (position == ListView.INVALID_POSITION)
      getListView().setItemChecked(mActivatedPosition, false);
    else
      getListView().setItemChecked(position, true);
    mActivatedPosition = position;
  }

  public final class StoryFetchTask extends AsyncTask<String, Boolean, String> {
    @Override
    protected String doInBackground(String... params) {
          Log.i(""+this, "Fetching stories, params: "+Arrays.toString(params)+", online: "+Util.AreWeOnline(getActivity()));
        publishProgress(true);
        String result = null;
        String time = (params==null || params.length<1 ? null : params[0]);
        String section = (params==null || params.length<2 ? null : params[1]);
        String source = (params==null || params.length<3 ? null : params[2]);
        String url = "http://www.scanvine.com/api/1";

        if (source!=null && source.length()>0)
          url += "/source/"+source;
        else if (section!=null && section.length()>0)
        url += "/"+section;
        if (time!=null && time.length()>0)
          url += "/"+time;

        String fileName = Util.ConvertUrlToFilename(url);
            File storiesFile = new File(getActivity().getCacheDir(), fileName);

            if (storiesFile.exists()) {
              boolean useCache = !Util.AreWeOnline(getActivity());
              useCache = useCache || params.length>3 && "cached".equalsIgnoreCase(params[3]);
              long age = System.currentTimeMillis() - storiesFile.lastModified();
              useCache = useCache || (age>0 && age < 600*1000);
                if (useCache) {
                  Log.i(""+this, "Using cached stories file");
                  result = Util.ConvertFileToString(storiesFile);
                  return result;
                }
            }

        HttpClient httpclient = new DefaultHttpClient();
          Log.i(""+this, "About to fetch "+url);
        try {
          HttpGet httpget = new HttpGet(url); 
          HttpResponse response = httpclient.execute(httpget);
            Log.i(""+this, "Fetch result: "+response);
            HttpEntity entity = response.getEntity();
            if (entity != null) {
                InputStream instream = entity.getContent();
                result = Util.ConvertStreamToString(instream);
                instream.close();
            }
        }
          catch (org.apache.http.NoHttpResponseException ex) {
                if (storiesFile.exists())
                  result = Util.ConvertFileToString(storiesFile);
                return result;
        } catch (Exception ex) {
          Log.e(""+this, "Fetch error: "+ex);
          ex.printStackTrace();
        }
        
        if (result!=null && result.length()>0) {
          //write to cache
            try {
                FileWriter out = new FileWriter(storiesFile);
                out.write(result);
                out.close();
                Log.i(""+this, "Cached results to "+storiesFile);
            } catch (IOException ex) {
                Log.e(""+this, "Write error: "+ex);
                ex.printStackTrace();
            }
        }
        return result;
    }
    
      @Override
    protected void onProgressUpdate(Boolean... progress) {
        mCallbacks.showProgress(progress[0]);
    }

    @Override
    protected void onPostExecute(String result) {
        publishProgress(false);
        if (result!=null && result.length()>0) {
          Log.i(""+this, "Got response of length "+result.length());
          stories = Story.GetStoriesFrom(result);
        }
        else
          stories = new ArrayList<Story>();
        renderStories();
    }
  }

  public final class ListDownloadsTask extends AsyncTask<String, Boolean, String> {
    @Override
    protected String doInBackground(String... params) {
        publishProgress(true);
      File[] files = getActivity().getFilesDir().listFiles();
      Arrays.sort(files, new Comparator<File>() {
          public int compare(File f1, File f2) {
            return Long.valueOf(f1.lastModified()).compareTo(f2.lastModified());
          }
      });

      ArrayList<Story> downloads = new ArrayList<Story>();
      for (File child : files) {
        if (child.getName().startsWith(Story.FILE_PREFIX)) {
          Log.i(""+this, "Found "+child);
          String contents = Util.ConvertFileToString(child);
          try {
            JSONObject json = new JSONObject(contents);
            Story story = Story.GetStoryFor(json.getString("story"));
            downloads.add(story);
          }
          catch(Exception ex) {
            Log.e(""+this, "Couldn't get story from "+child);
          }
        }
      }

      stories = downloads;
        return "done";
    }
    
      @Override
    protected void onProgressUpdate(Boolean... progress) {
        mCallbacks.showProgress(progress[0]);
    }

    @Override
    protected void onPostExecute(String result) {
        publishProgress(false);
        renderStories();
    }
  }
}
Java Source Code List
