GetJSONGET

// GetJSONGET - this is the class that does the JSON downloading
 
package com.domain.project.net;
 
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
 
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.methods.HttpGet;
import org.json.JSONArray;
import org.json.JSONException;
 
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnCancelListener;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.TrafficStats;
import android.net.http.AndroidHttpClient;
import android.os.AsyncTask;
 
import com.domain.project.debug.ELog;
import com.domain.project.interfaces.GetJSONListener;
 
 
/**
 * @author Janitha
 * 
 */
public class GetJSONGET extends AsyncTask<HttpGet, Void, JSONArray> {
 
  private ProgressDialog _progressDialog;
  private Context _context;
	private Boolean _showProgressDialog;
	private Boolean _devMode = false;
	private double _tx;
	private double _rx;
 
 
 
	public GetJSONGET(Context context, Boolean showProgressDialog, String message, Boolean cancelable, Boolean devMode) {
		_context = context;
		_showProgressDialog = showProgressDialog;
		_devMode = devMode;
 
		_progressDialog = new ProgressDialog(_context);
		_progressDialog.setMessage(message);
		_progressDialog.setIndeterminate(true);
 
		if (cancelable) {
			_progressDialog.setCancelable(true);
			_progressDialog.setOnCancelListener(new OnCancelListener() {
 
				@Override
				public void onCancel(DialogInterface dialog) {
					cancel(true);
 
					final Activity activity = (Activity) _context;
					activity.finish();
				}
			});
		}
 
		if (_devMode) {
			_tx = TrafficStats.getTotalTxBytes();
			_rx = TrafficStats.getTotalRxBytes();
		}
 
	}
 
 
 
	@Override
	protected JSONArray doInBackground(HttpGet... params) {
		return downloadAndParseJSON(params[0]);
	}
 
 
 
	@Override
	protected void onPreExecute() {
		if (_showProgressDialog) {
			_progressDialog.show();
		}
	}
 
 
 
	@Override
	protected void onPostExecute(JSONArray result) {
		if (_devMode) {
			double tx = TrafficStats.getTotalTxBytes();
			double rx = TrafficStats.getTotalRxBytes();
 
			ELog.d(getClass().getName(), Double.toString(Math.round((tx - _tx) / 1024)) + "kb Tx, " + Double.toString(Math.round((rx - _rx) / 1024)) + "kb Rx");
		}
		
 
		if (_showProgressDialog) {
			_progressDialog.dismiss();
		}
 
		if (result == null) {
			if (_devMode)
				ELog.w(getClass().getName(), "Nothing was retrieved");
		}
 
		try {
			((GetJSONListener) _context).onGetJSONComplete(result);
		} catch (Exception e) {
			ELog.e(getClass().getName(), "Is GetJSONListener implemented by the calling class?");
		}
		
	}
 
 
 
	@Override
	protected void onCancelled() {
		if (_devMode)
			ELog.i(getClass().getName(), "Loading cancelled!");
 
		_progressDialog.dismiss();
	}
 
 
 
	private JSONArray downloadAndParseJSON(HttpGet httpGet) {
		final long start = System.currentTimeMillis();
		final Boolean isOnline = checkInternet();
 
		if (!isOnline) {
			// Caused by: java.lang.RuntimeException: Can't create handler
			// inside thread that has not called Looper.prepare()
			// Toast.makeText(_context, "Network connectivity unavailable",
			// Toast.LENGTH_LONG).show();
 
			return null;
		}
		else {
			final AndroidHttpClient client = AndroidHttpClient.newInstance("Android");
 
			try {
				if (_devMode)
					ELog.i(getClass().getName(), "Downloading JSON from " + httpGet.getURI());
 
				// check whether the calling activity of this has set this's
				// status to cancelled
				if (isCancelled()) {
					return null;
				}
 
				final HttpResponse response = client.execute(httpGet);
				final int statusCode = response.getStatusLine().getStatusCode();
 
				// check whether the calling activity of this has set this's
				// status to cancelled
				if (isCancelled()) {
					return null;
				}
 
				if (statusCode != HttpStatus.SC_OK) {
					if (_devMode)
						ELog.w(getClass().getName(), "Error " + statusCode + " while downloading " + httpGet.getURI());
 
					return null;
				}
 
				final HttpEntity entity = response.getEntity();
 
				if (entity != null) {
					final InputStream inputStream = entity.getContent();
					final BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "utf-8"), 8);
					final StringBuilder builder = new StringBuilder();
 
					String line;
 
					while ((line = bufferedReader.readLine()) != null) {
						builder.append(line + "\n");
					}
 
					line = builder.toString();
					line = line.trim();
 
					final Character character = line.charAt(0);
 
					if (isAJSONArray(character) == false) {
						if (_devMode)
							ELog.i(getClass().getName(), "Data sent as a JSONObject. Converting to a JSONArray");
 
						line = "[" + line + "]";
					}
 
					if (inputStream != null) {
						inputStream.close();
					}
 
					entity.consumeContent();
 
					if (_devMode)
						ELog.i(getClass().getName(), "Downloading JSON from " + httpGet.getURI() + " successful");
 
					final long duration = System.currentTimeMillis() - start;
 
					if (_devMode)
						ELog.d(getClass().getName(), "Execution time = " + duration + "ms");
 
					return new JSONArray(line);
				}
			}
			catch (JSONException e) {
				if (_devMode)
					ELog.w(getClass().getName(), "Error parsing JSON." + e.toString());
			}
			catch (IOException e) {
				if (httpGet.isAborted()) {
					return null;
				}
				else {
					if (_devMode)
						ELog.w(getClass().getName(), "I/O Error while downloading " + httpGet.getURI());
				}
			}
			catch (Exception e) {
				if (_devMode)
					ELog.w(getClass().getName(), "Error -> " + e.toString());
			}
			finally {
				client.close();
			}
 
			return null;
		}
	}
 
 
 
	/**
	 * @param character
	 * @return Checks whether the returned data is sent as a JSONArray or a
	 *         JSONObject.
	 */
	private Boolean isAJSONArray(Character character) {
		if (character.toString().equals("[")) {
			return true;
		}
		else {
			return false;
		}
 
	}
 
 
 
	/**
	 * Check for Internet connectivity.
	 * 
	 * @return true if Internet connectivity is available, false if not.
	 */
	private Boolean checkInternet() {
		final ConnectivityManager connectivityManager = (ConnectivityManager) _context.getSystemService(Context.CONNECTIVITY_SERVICE);
		final NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
 
		if (networkInfo != null) {
			if (_devMode)
				ELog.i(getClass().getName(), "Internet is available");
			return true;
		}
		else {
			if (_devMode)
				ELog.i(getClass().getName(), "Internet is not available");
			return false;
		}
	}
 
}

GetJSONListener

// GetJSONListener - your Activity which wants to user GetJSONGET should implement this interface
package com.domain.project.interfaces;
 
import org.json.JSONArray;
 
 
/**
 * @author Janitha
 *
 */
public interface GetJSONListener {
 
  public void onGetJSONComplete(JSONArray data);
}