Java tutorial
package com.ebaotech.salesplatform.commons.helper; /* * Copyright (C) 2014 VenomVendor <info@VenomVendor.com>. * * 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. */ import android.annotation.TargetApi; import android.content.Context; import android.content.SharedPreferences; import android.content.SharedPreferences.Editor; import android.os.Build; import android.preference.PreferenceManager; import android.util.Log; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.util.ArrayList; import java.util.HashSet; import java.util.List; import java.util.Map; import java.util.Set; import android.app.Activity; /** * Modified version of {@link SharedPreferences}.<br> * Initiate <b>"SimpleSharedPreferences"</b> by passing {@linkplain Context}. * <p/> * <pre> * SimpleSharedPreferences mPreferences = new SimpleSharedPreferences(getApplicationContext()); * </pre> * <p/> * <u>Start <b>Modifying / Accessing</b> data in SimpleSharedPreferences.</u> * <p/> * <pre> * mPreferences.putString(key, value); * mPreferences.getString(key, defaultValue); * </pre> * <p/> * <b>DO NOT</b> to use {@link SharedPreferences#edit()} or {@link Editor#commit()} <br> * <br> * <em> Note: * <ul> * <li>Usage of <b>deprecated</b> methods throws {@linkplain InstantiationError}.</li> * <li>{@link #apply()} is available only after API-9</li> * <li>Throws <b>"ClassCastException"</b> if wrong key is passed</li> * </ul> * </em> * * @see Context#getSharedPreferences * @see SharedPreferences */ public class SimpleSharedPreferences implements SharedPreferences, Editor { private final String tag = getClass().getSimpleName().toString(); private SharedPreferences mSharedPreferences; private Editor mEditor; private final Context mContext; private boolean enableLog = false; /** * @param {@link Context} context */ public SimpleSharedPreferences(Context context) { mContext = context; mSharedPreferences = null; } /** * @return the status of Log */ public boolean isLogEnabled() { return enableLog; } /** * Enables/Disables printing LogValues. * * @param enableLog */ public void setLogEnabled(boolean enableLog) { this.enableLog = enableLog; } /** * Initiate's SharedPreferences. */ private void initiateSharedPreferences() { if (mSharedPreferences == null) { mSharedPreferences = PreferenceManager.getDefaultSharedPreferences(mContext); } } /** * Initiates SharedPreferences & Creates a new Editor for these preferences */ private void initAndEdit() { initiateSharedPreferences(); edit(); } /** * Increment's App opened count by <b>1</b> * * @return <b>true</b> on success */ public boolean incrementAppOpenedCount() { initAndEdit(); final int appOpenedCount = getAppOpenedCount(); if (enableLog) { Log.d(tag, "Count before updating " + appOpenedCount); } mEditor.putInt(KEYS.OPENED_TIMES_COUNT, (appOpenedCount + 1)); return commit(); } /** * @return The number of times the was opened. This will not autoupdate, everytime the app is opened.<br> * You should call {@link #incrementAppOpenedCount()} on {@link Activity#onStart()} to update this. */ public int getAppOpenedCount() { initiateSharedPreferences(); return mSharedPreferences.getInt(KEYS.OPENED_TIMES_COUNT, 0); } @Override public Editor putString(String key, String value) { initAndEdit(); mEditor.putString(key, value); commit(); return this; } @Override public Editor putStringSet(String key, Set<String> values) throws Error { final JSONArray jArray = new JSONArray(); for (final String value : values) { jArray.put(value); } final JSONObject json = new JSONObject(); try { json.put(key, jArray); putString(key, json.toString()); if (enableLog) { Log.i(key, json.toString()); } } catch (final JSONException e) { throw new Error(e); } return this; } @Override public Editor putInt(String key, int value) { initAndEdit(); mEditor.putInt(key, value); commit(); return this; } @Override public Editor putLong(String key, long value) { initAndEdit(); mEditor.putLong(key, value); commit(); return this; } @Override public Editor putFloat(String key, float value) { initAndEdit(); mEditor.putFloat(key, value); commit(); return this; } @Override public Editor putBoolean(String key, boolean value) { initAndEdit(); mEditor.putBoolean(key, value); commit(); return this; } @Override public Editor remove(String key) { initAndEdit(); mEditor.remove(key); commit(); return this; } @Override public Editor clear() { initAndEdit(); mEditor.clear(); commit(); return this; } /** * <h1><u>Do not use this method</u></h1> <br> */ @Deprecated @Override public boolean commit() throws InstantiationError { if (mEditor != null) { return mEditor.commit(); } throw new InstantiationError("\n ======================================== \nError : " + "Do not call " + tag + "'s `commit()`." + "\n This method is not supported directly." + " \n ======================================== \n"); } @TargetApi(Build.VERSION_CODES.GINGERBREAD) @Override public void apply() throws NoSuchMethodError { initAndEdit(); try { mEditor.apply(); } catch (final NoSuchMethodError e) { throw new NoSuchMethodError("\n ======================================== \nError : " + "This method is supported only from API-9 { i.e only above GINGERBREAD }" + " \n ======================================== \n"); } } @Override public Map<String, ?> getAll() throws ClassCastException { initiateSharedPreferences(); return mSharedPreferences.getAll(); } @Override public String getString(String key, String defValue) throws ClassCastException { initiateSharedPreferences(); try { return mSharedPreferences.getString(key, defValue); } catch (final ClassCastException e) { final String returnType = new Object() { }.getClass().getEnclosingMethod().getReturnType().toString(); throw new ClassCastException("\n ======================================== \nClassCastException : " + key + "'s value is not a " + returnType + " \n ======================================== \n"); } } @Override public Set<String> getStringSet(String key, Set<String> defValues) throws ClassCastException { initiateSharedPreferences(); final String jsonPref = getString(key, null); if (jsonPref == null) { return defValues; } final List<String> prefValues = new ArrayList<String>(); try { final JSONArray mJsonArray = new JSONObject(jsonPref).getJSONArray(key); for (int i = 0; i < mJsonArray.length(); i++) { prefValues.add(mJsonArray.getString(i)); } } catch (final JSONException e) { e.printStackTrace(); } try { return new HashSet<String>(prefValues); } catch (final ClassCastException e) { final String returnType = new Object() { }.getClass().getEnclosingMethod().getReturnType().toString(); throw new ClassCastException("\n ======================================== \nClassCastException : " + key + "'s value is not a " + returnType + " \n ======================================== \n"); } catch (final Exception e) { return defValues; } } @Override public int getInt(String key, int defValue) throws ClassCastException { initiateSharedPreferences(); try { return mSharedPreferences.getInt(key, defValue); } catch (final ClassCastException e) { final String returnType = new Object() { }.getClass().getEnclosingMethod().getReturnType().toString(); throw new ClassCastException("\n ======================================== \nClassCastException : " + key + "'s value is not an " + returnType + " \n ======================================== \n"); } } @Override public long getLong(String key, long defValue) throws ClassCastException { initiateSharedPreferences(); try { return mSharedPreferences.getLong(key, defValue); } catch (final ClassCastException e) { final String returnType = new Object() { }.getClass().getEnclosingMethod().getReturnType().toString(); throw new ClassCastException("\n ======================================== \nClassCastException : " + key + "'s value is not a " + returnType + " \n ======================================== \n"); } } @Override public float getFloat(String key, float defValue) throws ClassCastException { initiateSharedPreferences(); try { return mSharedPreferences.getFloat(key, defValue); } catch (final ClassCastException e) { final String returnType = new Object() { }.getClass().getEnclosingMethod().getReturnType().toString(); throw new ClassCastException("\n ======================================== \nClassCastException : " + key + "'s value is not a " + returnType + " \n ======================================== \n"); } } @Override public boolean getBoolean(String key, boolean defValue) throws ClassCastException { initiateSharedPreferences(); try { return mSharedPreferences.getBoolean(key, defValue); } catch (final ClassCastException e) { final String returnType = new Object() { }.getClass().getEnclosingMethod().getReturnType().toString(); throw new ClassCastException("\n ======================================== \nClassCastException : " + key + "'s value is not a " + returnType + " \n ======================================== \n"); } } @Override public boolean contains(String key) { initiateSharedPreferences(); return mSharedPreferences.contains(key); } /** * <h1><u>Do not use this method</u></h1> <br> */ @Deprecated @Override public Editor edit() throws InstantiationError { if (mEditor != null) { return mEditor; } if (mSharedPreferences == null) { throw new InstantiationError("\n ======================================== \nError : " + "Do not call " + tag + "'s `edit()`." + "\n This method is not supported directly." + " \n ======================================== \n"); } mEditor = mSharedPreferences.edit(); return mEditor; } @Override public void registerOnSharedPreferenceChangeListener(OnSharedPreferenceChangeListener listener) { initiateSharedPreferences(); mSharedPreferences.registerOnSharedPreferenceChangeListener(listener); } @Override public void unregisterOnSharedPreferenceChangeListener(OnSharedPreferenceChangeListener listener) { initiateSharedPreferences(); mSharedPreferences.registerOnSharedPreferenceChangeListener(listener); } /** * Holds Constants for Keys */ class KEYS { /** * The Constant Key for App Opened Count. */ final static String OPENED_TIMES_COUNT = "VEE_OPENEDTIMESCOUNT"; } }