Java tutorial
/** ** Copyright (c) 2010 Ushahidi Inc ** All rights reserved ** Contact: team@ushahidi.com ** Website: http://www.ushahidi.com ** ** GNU Lesser General Public License Usage ** This file may be used under the terms of the GNU Lesser ** General Public License version 3 as published by the Free Software ** Foundation and appearing in the file LICENSE.LGPL included in the ** packaging of this file. Please review the following information to ** ensure the GNU Lesser General Public License version 3 requirements ** will be met: http://www.gnu.org/licenses/lgpl.html. ** ** ** If you have questions regarding the use of this file, please contact ** Ushahidi developers at team@ushahidi.com. ** **/ package com.ushahidi.android.app.util; import java.io.BufferedWriter; import java.io.File; import java.io.FileWriter; import java.io.IOException; import java.text.DateFormat; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Collection; import java.util.Date; import java.util.Random; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import android.content.Context; import android.content.pm.PackageManager; import android.location.Criteria; import android.net.ConnectivityManager; import android.net.NetworkInfo; import android.os.Environment; import android.provider.Settings; import android.util.Log; import android.widget.Toast; import com.ushahidi.android.app.net.MainGeocoder; /** * This is a utility class that has common methods to be used by most clsses. * * @author eyedol */ public class Util { private static JSONObject jsonObject; private static NetworkInfo networkInfo; private static Random random = new Random(); private static final String VALID_EMAIL_PATTERN = "^[_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)*@" + "[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$"; private static Pattern pattern; private static Matcher matcher; /** * joins two strings together * * @param first * @param second * @return */ public static String joinString(String first, String second) { return first.concat(second); } /** * Converts a string integer * * @param value * @return */ public static int toInt(String value) { return Integer.parseInt(value); } /** * Capitalize any string given to it. * * @param text * @return capitalized string */ public static String capitalizeString(String text) { if (text.length() == 0) return text; return text.substring(0, 1).toUpperCase() + text.substring(1).toLowerCase(); } /** * Create csv * * @param Vector<String> text * @return csv */ public static String implode(Collection<String> text) { String implode = ""; int i = 0; for (String value : text) { implode += i == text.size() - 1 ? value : value + ","; i++; } return implode; } /** * Is there internet connection */ public static boolean isConnected(Context context) { ConnectivityManager connectivity = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE); networkInfo = connectivity.getActiveNetworkInfo(); // NetworkInfo info if (networkInfo != null && networkInfo.isConnected() && networkInfo.isAvailable()) { return true; } return false; } /*** Gets the state of Airplane Mode. * * @param context * * @return true if enabled. * */ public static boolean isAirplaneModeOn(Context context) { return Settings.System.getInt(context.getContentResolver(), Settings.System.AIRPLANE_MODE_ON, 0) != 0; } /** * Truncates any given text. * * @param String text - the text to be truncated * @return String */ public static String truncateText(String text) { if (text.length() > 30) { return text.substring(0, 25).trim() + ""; } else { return text; } } /** * Limit a string to defined length * * @param int limit - the total length * @param string limited - the limited string */ public static String limitString(String value, int length) { StringBuilder buf = new StringBuilder(value); if (buf.length() > length) { buf.setLength(length); buf.append(" ..."); } return buf.toString(); } /** * Format date into more readable format. * * @param date - the date to be formatted. * @return String */ public static String formatDate(String dateFormat, String date, String toFormat) { String formatted = ""; DateFormat formatter = new SimpleDateFormat(dateFormat); try { Date dateStr = formatter.parse(date); formatted = formatter.format(dateStr); Date formatDate = formatter.parse(formatted); formatter = new SimpleDateFormat(toFormat); formatted = formatter.format(formatDate); } catch (ParseException e) { e.printStackTrace(); } return formatted; } /** * For debugging purposes. Append content of a string to a file * * @param text */ public static void appendLog(String text) { File logFile = new File(Environment.getExternalStorageDirectory(), "ush_log.txt"); if (!logFile.exists()) { try { logFile.createNewFile(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } try { // BufferedWriter for performance, true to set append to file flag BufferedWriter buf = new BufferedWriter(new FileWriter(logFile, true)); buf.append(text); buf.newLine(); buf.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * Extract Google geocode JSON data * * @apram json_data - the json data to be formatted. * @return String */ public static String getFromLocation(double latitude, double longitude, Context context) { String json_data = ""; int status = 0; JSONArray jsonArray; try { if (Util.isConnected(context)) { json_data = MainGeocoder.reverseGeocode(latitude, longitude); } else { return ""; } if (json_data != null) { jsonObject = new JSONObject(json_data); status = jsonObject.getJSONObject("Status").getInt("code"); if (status == 200) { jsonArray = jsonObject.getJSONArray("Placemark"); return jsonArray.getJSONObject(0).getJSONObject("AddressDetails").getJSONObject("Country") .getJSONObject("AdministrativeArea").getJSONObject("Locality") .getString("LocalityName"); } else { return ""; } } } catch (JSONException e) { return ""; // e.printStackTrace(); } catch (IOException e) { return ""; } return ""; } /** * Show toast * * @param Context - the application's context * @param Int - string resource id * @return void */ public static void showToast(Context context, int i) { int duration = Toast.LENGTH_LONG; Toast.makeText(context, i, duration).show(); } /** * Validates an email address Credits: * http://www.mkyong.com/regular-expressions * /how-to-validate-email-address-with-regular-expression/ * * @param String - email address to be validated * @return boolean */ public static boolean validateEmail(String emailAddress) { if (!emailAddress.equals("")) { pattern = Pattern.compile(VALID_EMAIL_PATTERN); matcher = pattern.matcher(emailAddress); return matcher.matches(); } return true; } /** * Delete content of a folder recursively. * * @param String path - path to the directory. * @return void */ public static void rmDir(String path) { File dir = new File(path); if (dir.isDirectory()) { String[] children = dir.list(); Log.d("Directory", "dir.list returned some files" + children.length + "--"); for (int i = 0; i < children.length; i++) { File temp = new File(dir, children[i]); if (temp.isDirectory()) { rmDir(temp.getName()); } else { temp.delete(); } } dir.delete(); } else { Log.d("Directory", "This is not a directory" + path); } } /** * Capitalize each word in a text. * * @param String text - The text to be capitalized. * @return String */ public static String capitalize(String text) { if (text != null) { String[] words = text.split("\\s"); String capWord = ""; for (String word : words) { capWord += capitalizeString(word) + " "; return capWord; } } return ""; } /** this criteria will settle for less accuracy, high power, and cost */ public static Criteria createCoarseCriteria() { Criteria c = new Criteria(); c.setAccuracy(Criteria.ACCURACY_COARSE); c.setAltitudeRequired(false); c.setBearingRequired(false); c.setSpeedRequired(false); c.setCostAllowed(true); c.setPowerRequirement(Criteria.POWER_HIGH); return c; } /** this criteria needs high accuracy, high power, and cost */ public static Criteria createFineCriteria() { Criteria c = new Criteria(); c.setAccuracy(Criteria.ACCURACY_FINE); c.setAltitudeRequired(false); c.setBearingRequired(false); c.setSpeedRequired(false); c.setCostAllowed(true); c.setPowerRequirement(Criteria.POWER_HIGH); return c; } public static String generateFilename(boolean thumbnail) { if (thumbnail) { return randomString() + "_t.jpg"; } return randomString() + ".jpg"; } public static String randomString() { return Long.toString(Math.abs(random.nextLong()), 10); } /** * Checks that the device supports Camera. * * @param Context context - The calling activity's context. * @return boolean - True if it supports otherwise false. */ public static boolean deviceHasCamera(Context context) { PackageManager pm = context.getPackageManager(); if (pm.hasSystemFeature(PackageManager.FEATURE_CAMERA)) { return true; } else { return false; } } /** * Checks that the device supports Camera supports auto focus. * * @param Context context - The calling activity's context. * @return boolean - True if it supports otherwise false. */ public static boolean deviceCameraHasAutofocus(Context context) { PackageManager pm = context.getPackageManager(); if (pm.hasSystemFeature(PackageManager.FEATURE_CAMERA_AUTOFOCUS)) { return true; } else { return false; } } }