Source link:


SnappyDB is a key-value database for Android it's an alternative for SQLite if you want to use a NoSQL approach.

It allows you to store and get primitive types, but also a Serializable object or array in a type-safe way.

SnappyDB can outperform SQLite in read/write operations.

SnappyDB is based on leveldb and use snappy compression algorithm, on redundant content you could achieve a good compression ratio

Check out the Demo App


try {

 DB snappydb =;
 //create or open an existing database using the default name

  snappydb.put("name", "Jack Reacher");

  snappydb.putInt("age", 42);

snappydb.putBoolean("single", true);

 snappydb.put("books", new String[]{
"One Shot", "Tripwire", "61 Hours"

=  snappydb.get("name");

 =  snappydb.getInt("age");

 boolean  single =  snappydb.getBoolean("single");

 String[] books  =  snappydb.getArray("books", String.class);
// get array of string


 catch (SnappydbException e) {


For more recipes please take a look at the Cookbook.

With SnappyDB you could seamlessly store and retrieve your object/array, it uses Kryo serialization which is faster than the regular Java serialization.


SnappyDB uses native code for performance, it's available as an Android Library Project AAR.

dependencies {

  compile 'com.snappydb:snappydb-lib:0.5.2'
  compile 'com.esotericsoftware.kryo:kryo:2.24.0' 



  • Download JAR file and other folders from here
  • Put all the files and folders in the libs subfolder of your Android project
libs ????|?? snappydb-0.5.2.jar
  |?? armeabi
  ??? armeabi-v7a
  ??? mips
  ??? x86



Common tasks snippets

Create database

Create using the default name
 DB snappydb =;
Create with a given name
 DB snappydb =, "books");

SnappyDB use the internal storage to create your database. It creates a directory containing all the necessary files Ex: /data/data/com.snappydb/files/mydatabse

Using the builder pattern
 DB snappyDB = new SnappyDB.Builder(context)

.directory(Environment.getExternalStorageDirectory().getAbsolutePath()) //optional



directory Specify the location of the database ( sdcard in this example)

Close database


Destroy database


Insert primitive types

snappyDB.put("quote", "bazinga!");
  snappyDB.putShort("myshort", (short)32768);
  snappyDB.putInt("max_int", Integer.MAX_VALUE);
  snappyDB.putLong("max_long", Long.MAX_VALUE);
  snappyDB.putDouble("max_double", Double.MAX_VALUE);
  snappyDB.putFloat("myfloat", 10.30f);
  snappyDB.putBoolean("myboolean", true);

Read primitive types

String quote

= snappyDB.get("quote");
  short myshort
  = snappyDB.getShort("myshort");
  int maxInt

  = snappyDB.getInt("max_int");
  long maxLong

= snappyDB.getLong("max_long");
  double maxDouble  = snappyDB.getDouble("max_double");
  float myFloat
  = snappyDB.getFloat("myfloat");
  boolean myBoolean = snappyDB.getBoolean("myboolean");

Insert Serializable

AtomicInteger objAtomicInt = new AtomicInteger (42);
 snappyDB.put("atomic integer", objAtomicInt);

Insert Object

MyPojo pojo = new MyPojo ();
 snappyDB.put("my_pojo", pojo);

Note: MyPojo doesn't have to implement Serializable interface

Read Serializable

 AtomicInteger myObject = snappyDB.get("atomic integer", AtomicInteger.class);

Read Object

MyPojo myObject = snappyDB.getObject("non_serializable", MyPojo.class);

Note: MyPojo doesn't have to implement Serializable interface

Insert Array

Number[] array = {
new AtomicInteger (42), new BigDecimal("10E8"), Double.valueOf(Math.PI)
;  snappyDB.put("array", array);

Read Array

Number [] numbers = snappyDB.getObjectArray("array", Number.class);

Check Key

boolean isKeyExist = snappyDB.exists("key");

Delete Key


Keys Search

By Prefix
snappyDB.put("android:03", "Cupcake");
 // adding 0 to maintain lexicographical order snappyDB.put("android:04", "Donut");
 snappyDB.put("android:05", "Eclair");
 snappyDB.put("android:08", "Froyo");
 snappyDB.put("android:09", "Gingerbread");
 snappyDB.put("android:11", "Honeycomb");
 snappyDB.put("android:14", "Ice Cream Sandwich");
 snappyDB.put("android:16", "Jelly Bean");
 snappyDB.put("android:19", "KitKat");
  String [] keys = snappyDB.findKeys("android");
 assert keys.length == 9;  keys = snappyDB.findKeys("android:0");
 assert keys.length == 5;  assert snappyDB.get(keys[0]).equals("Cupcake");
 assert snappyDB.get(keys[1]).equals("Donut");
 assert snappyDB.get(keys[2]).equals("Eclair");
 assert snappyDB.get(keys[3]).equals("Froyo");
 assert snappyDB.get(keys[4]).equals("Gingerbread");
  keys = snappyDB.findKeys("android:1");
 assert keys.length == 4;  assert snappyDB.get(keys[0]).equals("Honeycomb");
 assert snappyDB.get(keys[1]).equals("Ice Cream Sandwich");
 assert snappyDB.get(keys[2]).equals("Jelly Bean");
 assert snappyDB.get(keys[3]).equals("KitKat");
By Range [from .. to]
  • both 'FROM' & 'TO' keys exist
keys = snappyDB.findKeysBetween("android:08", "android:11");
 assertEquals(3, keys.length);
 assertEquals("android:08", keys[0]);
 assertEquals("android:09", keys[1]);
 assertEquals("android:11", keys[2]);
  • 'FROM' key exist, but not the `TO
keys = snappyDB.findKeysBetween("android:05", "android:10");
 assertEquals(3, keys.length);
 assertEquals("android:05", keys[0]);
 assertEquals("android:08", keys[1]);
 assertEquals("android:09", keys[2]);
  • 'FROM' key doesn't exist but the 'TO' key do
keys = snappyDB.findKeysBetween("android:07", "android:09");
 assertEquals(2, keys.length);
 assertEquals("android:08", keys[0]);
 assertEquals("android:09", keys[1]);
  • both 'FROM' & 'TO' keys doesn't exist
keys = snappyDB.findKeysBetween("android:13", "android:99");
 assertEquals(3, keys.length);
 assertEquals("android:14", keys[0]);
 assertEquals("android:16", keys[1]);
 assertEquals("android:19", keys[2]);
With offset and limit
//return all keys starting with "android" after the first 5 keys = snappyDB.findKeys("android", 5);
 assertEquals(4, keys.length);
 assertEquals("android:11", keys[0]);
 assertEquals("android:14", keys[1]);
 assertEquals("android:16", keys[2]);
 assertEquals("android:19", keys[3]);
  //return 3 first keys starting with "android" keys = snappyDB.findKeys("android", 0, 3);
 assertEquals(3, keys.length);
 assertEquals("android:03", keys[0]);
 assertEquals("android:04", keys[1]);
 assertEquals("android:05", keys[2]);
  //return the fourth key starting with "android" (offset 3, limit 1) keys = snappyDB.findKeys("android", 3, 1);
 assertEquals(1, keys.length);
 assertEquals("android:08", keys[0]);
  //return the two first keys between android:14 and android:99 keys = snappyDB.findKeysBetween("android:14", "android:99", 0, 2);
 assertEquals(2, keys.length);
 assertEquals("android:14", keys[0]);
 assertEquals("android:16", keys[1]);
  //return the third key (offset 2, limit 1) after android:10 before android:99 keys = snappyDB.findKeysBetween("android:10", "android:99", 2, 1);
 assertEquals(1, keys.length);
 assertEquals("android:16", keys[0]);

Keys Count

Counting is quicker than extracting values (if you don't need them). Especially on very big collections.

By Prefix
assertEquals(9, snappyDB.countKeys("android"));
 assertEquals(5, snappyDB.countKeys("android:0"));
By Range [from .. to]
assertEquals(3, snappyDB.countKeysBetween("android:08", "android:11"));
 assertEquals(3, snappyDB.countKeysBetween("android:13", "android:99"));


Each time you use the offset & limit arguments, the engine makes the query and then scrolls to your offset. Which means that the bigger the offset is, the longer the query will take. This is not a problem on small collections, but on very larg collections, it is.

An iterator keeps it's position in the key collection and can be asked for the next key at any time. It is therefore better to use an iterator on very large collections.

Iterators work on DB snapshot, which means that if you add or delete value in / from the DB, the iterators will not see those changes.

Please note that iterators given by the SnappyDB are closeable and need to be closed once finished with. As iterators work on a DB snapshot, not closing them is a serious memory leak.

// An iterator to all keys it = snappyDB.allKeysIterator();
 /*...*/ it.close();
  // An iterator to all keys in reverse order it = snappyDB.allKeysReverseIterator();
 /*...*/ it.close();
  // An iterator to all keys including and after android:14 it = snappyDB.findKeysIterator("android:14");
 /*...*/ it.close();
  // An iterator to all keys from android:05 to android:10 it = snappyDB.findKeysBetweenIterator("android:05", "android:10");
 /*...*/ it.close();
  // An iterator to all keys from android:09 to android:05 in reverse order it = snappyDB.findKeysBetweenReverseIterator("android:09", "android:05");
 /*...*/ it.close();

Here are the methods implemented in KeyIterator :

public boolean hasNext();
 // Whether or not this is the last key. public String[] next(int max);
 // Get an array of next keys (maximum [max] keys). void close();
 // Closes the iterator. Iterable<String[]> byBatch(int size);
 // Get an iterable of key batch, each batch of maximum [size] keys.

Iterators work on key batchs (key arrays) and not directly on keys. You may iterate on all keys with the form:

for (String[] batch : db.findKeysIterator("android").byBatch(BATCH_SIZE)) {

  for (String key : batch) {


Please note that you should use the byBatch iterable to process all keys only on large collections. On reasonably small collections, using the array based APIs ( findKeys and findKeysBetween) with the form for (String key : db.findKeys("android")) is a lot more efficient.
Iterators should only be used to process large collections or for collection paging view / access.


SnappyDB is opensource, contribution and feedback are welcomed

Copyright 2013 Nabil HACHICHA.  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, 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. 

Follow @nabil_hachicha

<script>!function(d,s,id){ var js,fjs=d.getElementsByTagName(s)[0],p=/^http:/.test(d.location)?'http':'https';if(!d.getElementById(id)){ js=d.createElement(s);;js.src=p+'://';fjs.parentNode.insertBefore(js,fjs); } } (document, 'script', 'twitter-wjs'); </script> <script> (function(i,s,o,g,r,a,m){ i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments) } ,i[r].l=1*new Date(); a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) } )(window,document,'script','//','ga'); ga('create', 'UA-46288191-1', ''); ga('send', 'pageview'); </script>


An android custom view which allows you to have an arc style-menu on your pages.

RxJava style camera API for android, it is based on

A simple viewpager indicator that uses arrows on the left and right. You can navigate viewpager by clicking arrows and customize them as well.

This library is used to handle location requests and maintains the flow with permission checks in marshmallow.

EdittextWithTag allows to manage tags using spaces.

A custom view that animates like voice search button in Android TV.


2D Engines   3D Engines   9-Patch   Action Bars   Activities   ADB   Advertisements   Analytics   Animations   ANR   AOP   API   APK   APT   Architecture   Audio   Autocomplete   Background Processing   Backward Compatibility   Badges   Bar Codes   Benchmarking   Bitmaps   Bluetooth   Blur Effects   Bread Crumbs   BRMS   Browser Extensions   Build Systems   Bundles   Buttons   Caching   Camera   Canvas   Cards   Carousels   Changelog   Checkboxes   Cloud Storages   Color Analysis   Color Pickers   Colors   Comet/Push   Compass Sensors   Conferences   Content Providers   Continuous Integration   Crash Reports   Credit Cards   Credits   CSV   Curl/Flip   Data Binding   Data Generators   Data Structures   Database   Database Browsers   Date &   Debugging   Decompilers   Deep Links   Dependency Injections   Design   Design Patterns   Dex   Dialogs   Distributed Computing   Distribution Platforms   Download Managers   Drawables   Emoji   Emulators   EPUB   Equalizers &   Event Buses   Exception Handling   Face Recognition   Feedback &   File System   File/Directory   Fingerprint   Floating Action   Fonts   Forms   Fragments   FRP   FSM   Functional Programming   Gamepads   Games   Geocaching   Gestures   GIF   Glow Pad   Gradle Plugins   Graphics   Grid Views   Highlighting   HTML   HTTP Mocking   Icons   IDE   IDE Plugins   Image Croppers   Image Loaders   Image Pickers   Image Processing   Image Views   Instrumentation   Intents   Job Schedulers   JSON   Keyboard   Kotlin   Layouts   Library Demos   List View   List Views   Localization   Location   Lock Patterns   Logcat   Logging   Mails   Maps   Markdown   Mathematics   Maven Plugins   MBaaS   Media   Menus   Messaging   MIME   Mobile Web   Native Image   Navigation   NDK   Networking   NFC   NoSQL   Number Pickers   OAuth   Object Mocking   OCR Engines   OpenGL   ORM   Other Pickers   Parallax List   Parcelables   Particle Systems   Password Inputs   PDF   Permissions   Physics Engines   Platforms   Plugin Frameworks   Preferences   Progress Indicators   ProGuard   Properties   Protocol Buffer   Pull To   Purchases   Push/Pull   QR Codes   Quick Return   Radio Buttons   Range Bars   Ratings   Recycler Views   Resources   REST   Ripple Effects   RSS   Screenshots   Scripting   Scroll Views   SDK   Search Inputs   Security   Sensors   Services   Showcase Views   Signatures   Sliding Panels   Snackbars   SOAP   Social Networks   Spannable   Spinners   Splash Screens   SSH   Static Analysis   Status Bars   Styling   SVG   System   Tags   Task Managers   TDD &   Template Engines   Testing   Testing Tools   Text Formatting   Text Views   Text Watchers   Text-to   Toasts   Toolkits For   Tools   Tooltips   Trainings   TV   Twitter   Updaters   USB   User Stories   Utils   Validation   Video   View Adapters   View Pagers   Views   Watch Face   Wearable Data   Wearables   Weather   Web Tools   Web Views   WebRTC   WebSockets   Wheel Widgets   Wi-Fi   Widgets   Windows   Wizards   XML   XMPP   YAML   ZIP Codes