Java tutorial
package es.uma.lcc.tasks; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.ArrayList; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.StatusLine; import org.apache.http.client.ClientProtocolException; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.params.HttpClientParams; import org.apache.http.cookie.Cookie; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.params.BasicHttpParams; import org.apache.http.params.HttpParams; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import es.uma.lcc.lockpic.MainActivity; import es.uma.lcc.lockpic.PictureDetailsActivity; import es.uma.lcc.lockpic.MainActivity.CookieRefresherThread; import es.uma.lcc.nativejpegencoder.R; import android.accounts.AccountManager; import android.app.ProgressDialog; import android.content.Intent; import android.os.AsyncTask; import android.util.Log; import static es.uma.lcc.utils.Constants.*; /** * @author - Carlos Pars Pulido, Oct 2013 * * AsyncTasks which queries the server for regions and permissions on an * already encrypted picture. * * Copyright (C) 2014 Carlos Pars: carlosparespulido (at) gmail (dot) com * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ public class PictureDetailsTask extends AsyncTask<Void, Void, Void> { final static String LOG_ERROR = "PictureDetailsError"; boolean mIsFirstRun = true; boolean mIsAuthError = false; String mPicId; Cookie mCookie; MainActivity mMainActivity; ProgressDialog mProgressDialog; public PictureDetailsTask(MainActivity mainActivity, String picId) { mMainActivity = mainActivity; mPicId = picId; } public PictureDetailsTask(MainActivity mainActivity, String picId, boolean isFirstRun) { mMainActivity = mainActivity; mIsFirstRun = isFirstRun; mPicId = picId; } @Override public void onPreExecute() { mProgressDialog = new ProgressDialog(mMainActivity, ProgressDialog.THEME_HOLO_DARK); mProgressDialog.setTitle(R.string.connectingServerDialog); mProgressDialog.setMessage(mMainActivity.getString(R.string.pleaseWaitDialog)); mProgressDialog.setCancelable(false); mProgressDialog.setIndeterminate(true); mProgressDialog.show(); } @Override public Void doInBackground(Void... args) { DefaultHttpClient httpclient = new DefaultHttpClient(); int width, height; final HttpParams params = new BasicHttpParams(); HttpClientParams.setRedirecting(params, false); httpclient.setParams(params); String target = SERVERURL + "?" + QUERYSTRING_ACTION + "=" + ACTION_PICTUREDETAILS + "&" + QUERYSTRING_PICTUREID + "=" + mPicId; HttpGet httpget = new HttpGet(target); while (mCookie == null) mCookie = mMainActivity.getCurrentCookie(); httpget.setHeader("Cookie", mCookie.getName() + "=" + mMainActivity.getCurrentCookie().getValue()); try { HttpResponse response = httpclient.execute(httpget); StatusLine status = response.getStatusLine(); if (status.getStatusCode() != 200) { throw new IOException("Invalid response from server: " + status.toString()); } HttpEntity entity = response.getEntity(); if (entity != null) { InputStream inputStream = entity.getContent(); ByteArrayOutputStream content = new ByteArrayOutputStream(); // Read response into a buffered stream int readBytes = 0; byte[] sBuffer = new byte[256]; while ((readBytes = inputStream.read(sBuffer)) != -1) { content.write(sBuffer, 0, readBytes); } String result = new String(content.toByteArray()); try { JSONArray jsonArray = new JSONArray(result); if (jsonArray.length() == 0) { // should never happen Log.e(APP_TAG, LOG_ERROR + ": Malformed response from server"); } else { // Elements in a JSONArray keep their order JSONObject successState = jsonArray.getJSONObject(0); if (successState.get(JSON_RESULT).equals(JSON_RESULT_ERROR)) { if (successState.getBoolean(JSON_ISAUTHERROR) && mIsFirstRun) { mIsAuthError = true; } else { Log.e(APP_TAG, LOG_ERROR + ": Server found an error: " + successState.get(JSON_REASON)); } } else { ArrayList<String> users = new ArrayList<String>(); ArrayList<String> coords = new ArrayList<String>(); ArrayList<String> ids = new ArrayList<String>(); JSONObject obj = jsonArray.getJSONObject(0); width = obj.getInt(JSON_IMGWIDTH); height = obj.getInt(JSON_IMGHEIGHT); for (int i = 1; i < jsonArray.length(); i++) { obj = jsonArray.getJSONObject(i); users.add(obj.getString(JSON_USERNAME)); coords.add(formatCoordinates(obj.getInt(JSON_HSTART), obj.getInt(JSON_HEND), obj.getInt(JSON_VSTART), obj.getInt(JSON_VEND))); ids.add(obj.getString(JSON_PERMISSIONID)); } Intent intent = new Intent(mMainActivity, PictureDetailsActivity.class); intent.putStringArrayListExtra("users", users); intent.putStringArrayListExtra("coordinates", coords); intent.putStringArrayListExtra("ids", ids); intent.putExtra("height", height); intent.putExtra("width", width); intent.putExtra("picId", mPicId); intent.putExtra("username", mMainActivity.getUserEmail()); mMainActivity.startActivityForResult(intent, ACTIVITY_PICTURE_DETAILS); } } } catch (JSONException jsonEx) { Log.e(APP_TAG, LOG_ERROR + ": Malformed JSON response from server"); } } else { // entity is null Log.e(APP_TAG, LOG_ERROR + ": null response from server"); } } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return null; } @Override public void onPostExecute(Void arg) { mProgressDialog.dismiss(); if (mIsAuthError) handleAuthenticationError(); } private void handleAuthenticationError() { Thread t = new CookieRefresherThread(AccountManager.get(mMainActivity), mMainActivity); t.start(); try { t.join(); (new PictureDetailsTask(mMainActivity, mPicId, false)).execute(); } catch (InterruptedException e) { e.printStackTrace(); } } public String formatCoordinates(int x0, int xEnd, int y0, int yEnd) { return "(" + x0 * 16 + ", " + y0 * 16 + ") " + mMainActivity.getResources().getString(R.string.coordSeparator) + " (" + xEnd * 16 + ", " + yEnd * 16 + ")"; } }