Android Open Source - android-blog-reader Main List Activity

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License

The source code is released under:

MIT License

Java Source Code

package com.teamtreehouse.blogreader;
/*  www .  j  av  a2s  .co m*/
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.AlertDialog;
import android.app.ListActivity;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.text.Html;
import android.util.Log;
import android.view.View;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;

public class MainListActivity extends ListActivity {
  
  public static final int NUMBER_OF_POSTS = 20;
  public static final String TAG = MainListActivity.class.getSimpleName();
  protected JSONObject mBlogData;
  protected ProgressBar mProgressBar;
  
  private final String KEY_TITLE = "title";
  private final String KEY_AUTHOR = "author";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_list);
        
        mProgressBar = (ProgressBar) findViewById(R.id.progressBar1);
        
        if (isNetworkAvailable()) {
          mProgressBar.setVisibility(View.VISIBLE);
          GetBlogPostsTask getBlogPostsTask = new GetBlogPostsTask();
          getBlogPostsTask.execute();
        }
        else {
          Toast.makeText(this, "Network is unavailable!", Toast.LENGTH_LONG).show();
        }
        
        //Toast.makeText(this, getString(R.string.no_items), Toast.LENGTH_LONG).show();
    }
    
    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
      super.onListItemClick(l, v, position, id);
      try {
        JSONArray jsonPosts = mBlogData.getJSONArray("posts");
        JSONObject jsonPost = jsonPosts.getJSONObject(position);
        String blogUrl = jsonPost.getString("url");
        
        Intent intent = new Intent(this, BlogWebViewActivity.class);
        intent.setData(Uri.parse(blogUrl));
        startActivity(intent);
      }
      catch (JSONException e) {
        logException(e);
      }
    }

    private void logException(Exception e) {
      Log.e(TAG, "Exception caught!", e);
  }

  private boolean isNetworkAvailable() {
    ConnectivityManager manager = (ConnectivityManager) 
        getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = manager.getActiveNetworkInfo();
    
    boolean isAvailable = false;
    if (networkInfo != null && networkInfo.isConnected()) {
      isAvailable = true;
    }
    
    return isAvailable;
  }

  public void handleBlogResponse() {
    mProgressBar.setVisibility(View.INVISIBLE);
    
    if (mBlogData == null) {
      updateDisplayForError();
    }
    else {
      try {
        JSONArray jsonPosts = mBlogData.getJSONArray("posts");
        ArrayList<HashMap<String, String>> blogPosts = 
            new ArrayList<HashMap<String, String>>();
        for (int i = 0; i < jsonPosts.length(); i++) {
          JSONObject post = jsonPosts.getJSONObject(i);
          String title = post.getString(KEY_TITLE);
          title = Html.fromHtml(title).toString();
          String author = post.getString(KEY_AUTHOR);
          author = Html.fromHtml(author).toString();
          
          HashMap<String, String> blogPost = new HashMap<String, String>();
          blogPost.put(KEY_TITLE, title);
          blogPost.put(KEY_AUTHOR, author);
          
          blogPosts.add(blogPost);
        }
        
        String[] keys = { KEY_TITLE, KEY_AUTHOR };
        int[] ids = { android.R.id.text1, android.R.id.text2 };
        SimpleAdapter adapter = new SimpleAdapter(this, blogPosts,
            android.R.layout.simple_list_item_2, 
            keys, ids);
        
        setListAdapter(adapter);
      } 
      catch (JSONException e) {
        logException(e);
      }
    }
  }

  private void updateDisplayForError() {
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle(getString(R.string.error_title));
    builder.setMessage(getString(R.string.error_message));
    builder.setPositiveButton(android.R.string.ok, null);
    AlertDialog dialog = builder.create();
    dialog.show();
    
    TextView emptyTextView = (TextView) getListView().getEmptyView();
    emptyTextView.setText(getString(R.string.no_items));
  }
    
    private class GetBlogPostsTask extends AsyncTask<Object, Void, JSONObject> {

    @Override
    protected JSONObject doInBackground(Object... arg0) {
      int responseCode = -1;
      JSONObject jsonResponse = null;
      
          try {
            URL blogFeedUrl = new URL("http://blog.teamtreehouse.com/api/get_recent_summary/?count=" + NUMBER_OF_POSTS);
            HttpURLConnection connection = (HttpURLConnection) blogFeedUrl.openConnection();
            connection.connect();
            
            responseCode = connection.getResponseCode();
            if (responseCode == HttpURLConnection.HTTP_OK) {
              InputStream inputStream = connection.getInputStream();
              Reader reader = new InputStreamReader(inputStream);
              int contentLength = connection.getContentLength();
              char[] charArray = new char[contentLength];
              reader.read(charArray);
              String responseData = new String(charArray);
              
              jsonResponse = new JSONObject(responseData);
            }
            else {
              Log.i(TAG, "Unsuccessful HTTP Response Code: " + responseCode);
            }
          }
          catch (MalformedURLException e) {
            logException(e);
          }
          catch (IOException e) {
            logException(e);
          }
          catch (Exception e) {
            logException(e);
          }
          
          return jsonResponse;
    }
    
    @Override
    protected void onPostExecute(JSONObject result) {
      mBlogData = result;
      handleBlogResponse();
    }
      
    }
    
}

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