v1.0.3 (Aug 10, 2017)
Aug 4, 2015
Mar 18, 2018
Dimitry (noties)
Dimitry (noties)
Source code
APK file


SharedPreferencesGenerator (SPG)

A simple tool for code generation of android.content.SharedPreferences based on model class described in java with a little help of annotations. Provides an ability to encapsulate data, saves time writing boiler-plate code, goes beyond SharedPreferences usage with easy-to use Serialization & default values evaluation at runtime.



compile 'ru.noties.spg:core:1.0.4'


annotationProcessor 'ru.noties.spg:processor:1.0.4'

The generated classes could be found under {moduleName}/build/generated/source/apt/* and will have the same package as the class annotated with @SPGPreference. Please also note, that with every change to the source class (annotated with @SPGPreference) project must be rebuild to reflect latest changes.


Create a java object to describe your future SharedPreferences model & annotate it with ru.noties.spg.anno.SPGPreference. The simplest usage would be:

class Simplest {
 String someString;
 long someLong;
 int someInt;
 boolean someBool;

With a little help of SPG library you will get a lof of useful information of a preference via constansts (no more magic values); human readable getters & setters; some useful methods from ru.noties.spg.SPGPreferenceObject interface. A generated code for the Simplest class would look like:

// This file is generated by SharedPreferencesGenerator library at Thu Sep 03 12:13:57 FET 2015
// The description for this preference was taken from: ru.noties.spg.sample.pref.Preferences.Simplest
// Do not modify this file

public class SimplestPreference implements SPGPreferenceObject {

    public static final String PREFERENCE_NAME = "Simplest";
    public static final int PREFERENCE_MODE = 0;

    public static final long DEF_LONG = -1L;
    public static final int DEF_INT = -1;
    public static final float DEF_FLOAT = .0F;
    public static final boolean DEF_BOOL = false;
    public static final String DEF_STRING = null;

    public static final String KEY_SOME_STRING = "someString";
    public static final String KEY_SOME_LONG = "someLong";
    public static final String KEY_SOME_INT = "someInt";
    public static final String KEY_SOME_BOOL = "someBool";

    private final SharedPreferences prefs;
    private final SharedPreferences.Editor editor;

    public SimplestPreference(Context context) {
        this.prefs = context.getSharedPreferences(PREFERENCE_NAME, 0);
        this.editor = prefs.edit();

    public java.lang.String getSomeString() {
        return prefs.getString("someString", DEF_STRING);

    public long getSomeLong() {
        return prefs.getLong("someLong", DEF_LONG);

    public int getSomeInt() {
        return prefs.getInt("someInt", DEF_INT);

    public boolean isSomeBool() {
        return prefs.getBoolean("someBool", DEF_BOOL);

    public void setSomeString(java.lang.String value) {
        editor.putString("someString", value).apply();

    public void setSomeLong(long value) {
        editor.putLong("someLong", value).apply();

    public void setSomeInt(int value) {
        editor.putInt("someInt", value).apply();

    public void setSomeBool(boolean value) {
        editor.putBoolean("someBool", value).apply();

    public Map<String, Object> toMap() {
        final Map<String, Object> map = new HashMap<String, Object>();
        map.put("someString", getSomeString());
        map.put("someLong", getSomeLong());
        map.put("someInt", getSomeInt());
        map.put("someBool", isSomeBool());
        return map;

    public SharedPreferences getSharedPreferences() {
        return prefs;

    public SharedPreferences.Editor getEditor() {
        return editor;

    public String getSharedPreferencesName() {
        return PREFERENCE_NAME;

    public int getSharedPreferencesMode() {
        return PREFERENCE_MODE;

    public <T> T get(String key) {
        if (key == null) { return null; }
        final Object o;
        if (key.equals("someString")) {
            o = getSomeString();
        } else if (key.equals("someLong")) {
            o = getSomeLong();
        } else if (key.equals("someInt")) {
            o = getSomeInt();
        } else if (key.equals("someBool")) {
            o = isSomeBool();
        } else {
            // not in this prefs;
            o = null;
        return (T) o;

    public Setter setter() {
        return new Setter(editor);

    public static final class Setter {

        private final SharedPreferences.Editor editor;

        Setter(SharedPreferences.Editor editor) {
            this.editor = editor;

        public Setter setSomeString(java.lang.String value) {
            editor.putString("someString", value);
            return this;

        public Setter setSomeLong(long value) {
            editor.putLong("someLong", value);
            return this;

        public Setter setSomeInt(int value) {
            editor.putInt("someInt", value);
            return this;

        public Setter setSomeBool(boolean value) {
            editor.putBoolean("someBool", value);
            return this;

        public void apply() { editor.apply(); }



String name() default "";
String defaultName() default "";
int sharedPreferenceMode() default 0;
String[] imports() default {};
boolean isSingleton() default false;

name - the output name of this shared preference. If not set, the class name would used (in the example above it will be Simplest)

sharedPreferenceMode - well, the shared preference mode

The above 2 are well known via context.getSharedPreferences(**name**, **sharedPreferencesMode**)

defaultName - the default SharedPreferences name will be used (as in call android.preference.PreferenceManager.getDefaultSharedPreferences(context))

imports - is a simple way to actually import a certain java package/packages. This comes at handy when dealing with runtime code evaluation (on which later)

isSingleton - should be self describing. The only thing that should be noted is that if a preference is marked as a singleton, a SPGManager.setContextProvider(ru.noties.spg.ContextProvider provider) must be called first (before calling getInstance() method). The best place to set ContextProvider is Application's onCreate() method.

Additionally @SPGPreference gives you ability to set this-preference-wide default values (default values for a specific field could be set via @SPGKey on which a little later):

String defBool() default "false";
String defInt() default "-1";
String defLong() default "-1L";
String defFloat() default "Float.NaN";
String defString() default "null";


Additionally each field of @SPGPreferences annotated class could be annotated with @SPGKey:

String name() default "";
String defaultValue() default "";
Class<?> serializer() default Void.class;
boolean onUpdate() default false;

name - shared preference key name (preference.getString("key", null)). If not set the field's name would be used

defaultValue - default value for this key. Should be a string. ("-1", ".0F", etc.). Also could be evaluated at runtime if set like: "${System.currentTimeMillis()}"

serializer - is a class of serializer if this key is serialized (must implement SPGSerializer<TYPE, REPRESENTATION>)

onUpdate - indicates that SPG library should generate a set*OnUpdateListener() and listen to the changes that occur with this key

Imports & code evaluation

Default value for a key could be evaluted at runtime. Evaluation values must match ${.+} pattern.

@SPGKey(defaultValue = "${System.currentTimeMillis()}")
private long firstLaunch;

There are no predefined evaluations, all code could be evaluated. For example

package com.example;
public class SomeClass {
 public static String getString() {...}
@SPGPreference(imports = "com.example.SomeClass")
public class MyPrefs {
 @SPGKey(defaultValue = "${SomeClass.getString()}")
 String someKey;

or just:

public class MyPrefs {
 @SPGKey(defaultValue = "${com.example.SomeClass.getString()}")
 String someKey;


Each key of a preference file could be serialized. It gives an ability to store any data with proper serialization.

@SPGKey(serializer = DateSerializer.class)
Date lastLaunch;

Where DateSerializer is a class that implements SPGSerializer<TYPE, REPRESENTATION>

public interface SPGSerializer<TYPE, REPRESENTATION> {
    TYPE deserialize(REPRESENTATION representation);
    REPRESENTATION serialize(TYPE type);
public class DateSerializer implements SPGSerializer<Date, Long> {

    private final long NO_DATE = -1L;

    public Date deserialize(Long aLong) {
        final long date = aLong;
        if (date == NO_DATE) {
            return null;
        return new Date(date);

    public Long serialize(Date date) {
        if (date == null) {
            return NO_DATE;
        return date.getTime();

Please note, that a REPRESENTATION must be one of the SharedPreferences supported types:

  • Boolean
  • Integer
  • Long
  • Float
  • String


Every generated class would implement SPGPreferenceObject, which contains some useful methods

public interface SPGPreferenceObject {

    String getSharedPreferencesName();
    int getSharedPreferencesMode();
    SharedPreferences getSharedPreferences();
    SharedPreferences.Editor getEditor();
    Map<String, Object> toMap();

    <T> T get(String key);


  Copyright 2016 Dimitry Ivanov (

  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

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  See the License for the specific language governing permissions and
  limitations under the License.