Java tutorial
/* Copyright 2014 Google Inc. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.tum.atse; import com.google.android.gms.auth.GoogleAuthUtil; import com.google.android.gms.common.GooglePlayServicesUtil; import com.google.api.client.util.DateTime; import android.Manifest; import android.accounts.Account; import android.accounts.AccountManager; import android.app.Activity; import android.app.AlertDialog; import android.app.Dialog; import android.content.Context; import android.content.DialogInterface; import android.content.SharedPreferences; import android.content.pm.PackageManager; import android.preference.PreferenceManager; import android.support.v4.app.ActivityCompat; import android.text.TextUtils; import android.text.format.DateUtils; import java.util.Calendar; /** * A general utility class. All methods here are static and no state is maintained. */ public class Utils { private static final String LOG_TAG = "Utils"; private final static String PREFS_KEY_EMAIL = "email_account"; private static final int MY_PERMISSIONS_REQUEST_READ_CONTACTS = 21; /** * Persists the email address to preference storage space. * * @param context * @param email */ public static void saveEmailAccount(Context context, String email) { saveStringToPreference(context, PREFS_KEY_EMAIL, email); } /** * Returns the persisted email account, or <code>null</code> if none found. * * @param context * @return */ public static String getEmailAccount(Context context) { return getStringFromPreference(context, PREFS_KEY_EMAIL); } /** * Saves a string value under the provided key in the preference manager. If <code>value</code> * is <code>null</code>, then the provided key will be removed from the preferences. * * @param context * @param key * @param value */ public static void saveStringToPreference(Context context, String key, String value) { SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(context); if (null == value) { // we want to remove pref.edit().remove(key).apply(); } else { pref.edit().putString(key, value).apply(); } } /** * Retrieves a String value from preference manager. If no such key exists, it will return * <code>null</code>. * * @param context * @param key * @return */ public static String getStringFromPreference(Context context, String key) { SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(context); return pref.getString(key, null); } /** * Returns a detailed description of a conference. * * @param context * @param conference * @return */ /* public static String getConferenceCard(Context context, Conference conference) { StringBuffer sb = new StringBuffer(); if (!TextUtils.isEmpty(conference.getDescription())) { sb.append(conference.getDescription() + "\n"); } if (null != conference.getStartDate()) { sb.append("\n" + getConferenceDate(context, conference)); } if (!TextUtils.isEmpty(conference.getCity())) { sb.append("\n" + conference.getCity()); } if (null != conference.getMaxAttendees()) { sb.append("\n" + context.getString(R.string.seats_max, conference.getMaxAttendees().intValue())); } if (null != conference.getSeatsAvailable()) { sb.append("\n" + context.getString(R.string.seats_available, conference.getSeatsAvailable().intValue())); } return sb.toString(); } *//** * Returns the date of a conference. * * @param context * @param conference * @return *//* public static String getConferenceDate(Context context, Conference conference) { StringBuffer sb = new StringBuffer(); if (null != conference.getStartDate() && null != conference.getEndDate()) { sb.append(getFormattedDateRange(context, conference.getStartDate(), conference.getEndDate())); } else if (null != conference.getStartDate()) { sb.append(getFormattedDate(context, conference.getStartDate())); } return sb.toString(); } */ /** * Returns a user-friendly localized date. * * @param context * @param dateTime * @return */ public static String getFormattedDate(Context context, DateTime dateTime) { Calendar cal = Calendar.getInstance(); cal.setTimeInMillis(dateTime.getValue()); return DateUtils.formatDateTime(context, cal.getTimeInMillis(), DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_ABBREV_MONTH); } /** * Returns a user-friendly localized data range. * * @param context * @param dateTimeStart * @param dateTimeEnd * @return */ public static String getFormattedDateRange(Context context, DateTime dateTimeStart, DateTime dateTimeEnd) { Calendar cal1 = Calendar.getInstance(); cal1.setTimeInMillis(dateTimeStart.getValue()); Calendar cal2 = Calendar.getInstance(); cal2.setTimeInMillis(dateTimeEnd.getValue()); return DateUtils.formatDateRange(context, cal1.getTimeInMillis(), cal2.getTimeInMillis(), DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_ABBREV_MONTH); } /** * Check that Google Play services APK is installed and up to date. */ public static boolean checkGooglePlayServicesAvailable(Activity activity) { final int connectionStatusCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(activity); if (GooglePlayServicesUtil.isUserRecoverableError(connectionStatusCode)) { showGooglePlayServicesAvailabilityErrorDialog(activity, connectionStatusCode); return false; } return true; } /** * Called if the device does not have Google Play Services installed. */ public static void showGooglePlayServicesAvailabilityErrorDialog(final Activity activity, final int connectionStatusCode) { final int REQUEST_GOOGLE_PLAY_SERVICES = 0; activity.runOnUiThread(new Runnable() { @Override public void run() { Dialog dialog = GooglePlayServicesUtil.getErrorDialog(connectionStatusCode, activity, REQUEST_GOOGLE_PLAY_SERVICES); dialog.show(); } }); } /** * Displays error dialog when a network error occurs. Exits application when user confirms * dialog. * * @param context */ public static void displayNetworkErrorMessage(Context context) { new AlertDialog.Builder(context).setTitle("Api Error Title").setMessage("Api Error Message") .setCancelable(false).setPositiveButton("Close", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int id) { System.exit(0); } }).create().show(); } }