Java tutorial
/* * Copyright (C) 2011 Google Inc. * * 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.android.utils; import android.content.Context; import android.content.SharedPreferences; import android.content.res.Resources; import android.preference.PreferenceManager; import android.support.v4.content.ContextCompat; import android.support.v4.os.BuildCompat; /** * Utility methods for interacting with {@link SharedPreferences} objects. */ public class SharedPreferencesUtils { /** * Returns the value of an integer preference stored as a string. This is * necessary when using a {@link android.preference.ListPreference} to * manage an integer preference, since the entries must be {@link String} * values. * * @param prefs Shared preferences from which to obtain the value. * @param res Resources from which to obtain the key and default value. * @param keyResId Resource identifier for the key. * @param defaultResId Resource identifier for the default value. * @return The preference value, or the default value if not set. */ public static int getIntFromStringPref(SharedPreferences prefs, Resources res, int keyResId, int defaultResId) { final String strPref = prefs.getString(res.getString(keyResId), res.getString(defaultResId)); return Integer.parseInt(strPref); } /** * Returns the value of a floating point preference stored as a string. This * is necessary when using a {@link android.preference.ListPreference} to * manage a floating point preference, since the entries must be * {@link String} values. * * @param prefs Shared preferences from which to obtain the value. * @param res Resources from which to obtain the key and default value. * @param keyResId Resource identifier for the key. * @param defaultResId Resource identifier for the default value. * @return The preference value, or the default value if not set. */ public static float getFloatFromStringPref(SharedPreferences prefs, Resources res, int keyResId, int defaultResId) { final String strPref = prefs.getString(res.getString(keyResId), res.getString(defaultResId)); return Float.parseFloat(strPref); } /** * Returns the value of a string preference. * * @param prefs Shared preferences from which to obtain the value. * @param res Resources from which to obtain the key and default value. * @param keyResId Resource identifier for the key. * @param defaultResId Resource identifier for the default value. * @return The preference value, or the default value if not set. */ public static String getStringPref(SharedPreferences prefs, Resources res, int keyResId, int defaultResId) { return prefs.getString(res.getString(keyResId), ((defaultResId == 0) ? null : res.getString(defaultResId))); } /** * Returns the value of a boolean preference. * * @param prefs Shared preferences from which to obtain the value. * @param res Resources from which to obtain the key and default value. * @param keyResId Resource identifier for the key. * @param defaultResId Resource identifier for the default value. * @return The preference value, or the default value if not set. */ public static boolean getBooleanPref(SharedPreferences prefs, Resources res, int keyResId, int defaultResId) { return prefs.getBoolean(res.getString(keyResId), res.getBoolean(defaultResId)); } /** * Stores the value of a boolean preference. * * @param prefs Shared preferences from which to obtain the value. * @param res Resources from which to obtain the key and default value. * @param keyResId Resource identifier for the key. * @param value The value to store. */ public static void putBooleanPref(SharedPreferences prefs, Resources res, int keyResId, boolean value) { storeBooleanAsync(prefs, res.getString(keyResId), value); } /** * Stores the value of a boolean preference async. * * @param prefs Shared preferences from which to obtain the value. * @param key The pref key * @param value The value to store. */ public static void storeBooleanAsync(SharedPreferences prefs, String key, boolean value) { SharedPreferences.Editor editor = prefs.edit(); editor.putBoolean(key, value); editor.apply(); } /** * Gets the appropriate SharedPreferences depending on the device capabilities. * On systems that support device-protected storage (Android N or later with compatible device), * returns SharedPreferences backed by device-protected storage. * Otherwise, returns SharedPreferences backed by a standard credential-protected storage * context. */ public static SharedPreferences getSharedPreferences(Context context) { Context deContext = ContextCompat.createDeviceProtectedStorageContext(context); if (deContext != null) { return PreferenceManager.getDefaultSharedPreferences(deContext); } else { return PreferenceManager.getDefaultSharedPreferences(context); } } /** * Move existing preferences file from credential protected storage to device protected storage. * This is used to migrate data between storage locations after an Android upgrade from * Build.VERSION < N to Build.VERSION >= N. */ public static void migrateSharedPreferences(Context context) { if (BuildCompat.isAtLeastN()) { Context deContext = ContextCompat.createDeviceProtectedStorageContext(context); deContext.moveSharedPreferencesFrom(context, PreferenceManager.getDefaultSharedPreferencesName(context)); } } }