Prefser

Wrapper for Android SharedPreferences with object serialization and RxJava Observables

min sdk version = 14

JavaDoc is available at: http://pwittchen.github.io/prefser/RxJava2.x

This is RxJava2.x branch. To see documentation for RxJava1.x, switch to RxJava1.x branch.

Overview
Creating Prefser object
Saving data
Reading data
Contains method
Removing data
Size of data
Getting SharedPreferences object
Subscribing for data updates
Examples
Download
Tests
Code style
Static code analysis
Caveats
Who is using this library?
References
License

Overview

Prefser wraps SharedPreferences and thanks to Java Generics provides you simpler API than classic SharedPreferences with the following methods:

<T> void put(String key, T value)
<T> T get(String key, Class<T> classOfT, T defaultValue)

We can also use TypeToken (e.g. for reading serialized Lists):

<T> T get(String key, TypeToken<T> typeTokenOfT, T defaultValue)

Prefser will serialize Lists correctly in put(...) method and will use TypeToken under the hood.

Classic SharedPreferences allows you to store only primitive data types, Strings and Set of Strings.

Thanks to Gson serialization, Prefser allows you to store:

Primitive data types
- boolean
- float
- int
- long
- double
Strings
Custom Objects
Lists
Arrays
Sets

In addition, Prefser transforms OnSharedPreferenceChangeListener into Observable from RxJava:

Observable<String> observePreferences();

You can subscribe one of this Observable and monitor updates of SharedPreferences with powerful RxJava. You can also read data from RxJava Observables in order to monitor single shared preference with a specified key.

Creating Prefser object

You can create Prefser object in the following ways:

Prefser prefser = new Prefser(context);
Prefser prefser = new Prefser(sharedPreferences);

When you create Prefser object with Android Context, it will use default SharedPreferences from PreferenceManager.

You can set JsonConverter implementation for Prefser. When it's not set, Prefser will use GsonConverter by default.

Prefser prefser = new Prefser(context, jsonConverter);
Prefser prefser = new Prefser(sharedPreferences, jsonConverter);

Saving data

You can save data with the following method:

<T> void put(String key, T value)

Examples

prefser.put("key", true);               // put boolean
prefser.put("key", 43f);                // put float
prefser.put("key", 42);                 // put int
prefser.put("key", 42l);                // put long
prefser.put("key", 42.3);               // put double
prefser.put("key", "hello");            // put String
prefser.put("key", new CustomObject()); // put CustomObject

prefser.put("key", Arrays.asList(true, false, true));     // put list of booleans
prefser.put("key", Arrays.asList(1f, 2f, 3f));            // put list of floats
prefser.put("key", Arrays.asList(1, 2, 3));               // put list of integers
prefser.put("key", Arrays.asList(1l, 2l, 3l));            // put list of longs
prefser.put("key", Arrays.asList(1.2, 2.3, 3.4));         // put list of doubles
prefser.put("key", Arrays.asList("one", "two", "three")); // put list of Strings

List<CustomClass> objects = Arrays.asList(
  new CustomObject(),
  new CustomObject(),
  new CustomObject());

prefser.put(givenKey, objects); // put list of CustomObjects

prefser.put("key", new Boolean[]{true, false, true});     // put array of booleans
prefser.put("key", new Float[]{1f, 2f, 3f});              // put array of floats
prefser.put("key", new Integer[]{1, 2, 3});               // put array of integers
prefser.put("key", new Long[]{1l, 2l, 3l});               // put array of longs
prefser.put("key", new Double[]{1.2, 2.3, 3.4});          // put array of doubles
prefser.put("key", new String[]{"one", "two", "three"});  // put array of Strings

CustomObject[] objects = new CustomObject[]{
  new CustomObject(),
  new CustomObject(),
  new CustomObject()
};

prefser.put("key", objects); // put array of CustomObjects

Set<String> setOfStrings = new HashSet<>(Arrays.asList("one", "two", "three"));
Set<Double> setOfDoubles = new HashSet<>(Arrays.asList(1.2, 3.4, 5.6));
prefser.getPreferences().edit().putStringSet("key", setOfStrings).apply(); // put Set of Strings in a "classical way"
prefser.put("key", setOfDoubles); // put set of doubles

Reading data

get method

You can read data with the following method:

<T> T get(String key, Class<T> classOfT, T defaultValue)

or with TypeToken (e.g. when reading Lists):

<T> T get(String key, TypeToken<T> typeTokenOfT, T defaultValue)

Examples


// reading primitive types

Boolean value = prefser.get("key", Boolean.class, false);
Float value = prefser.get("key", Float.class, 1.0f);
Integer value = prefser.get("key", Integer.class, 1);
Long value = prefser.get("key", Long.class, 1.0l);
Double value = prefser.get("key", Double.class, 1.0);
String value = prefser.get("key", String.class, "default string");

// reading custom object

CustomObject value = prefser.get("key", CustomObject.class, new CustomObject());

// reading lists

// example with List of Booleans

List<Boolean> defaultBooleans = Arrays.asList(false, false, false);

TypeToken<List<Boolean>> typeToken = new TypeToken<List<Boolean>>() {
};

List<Boolean> readObject = prefser.get(givenKey, typeToken, defaultBooleans);

// in the same way we can read list of objects of any type including custom objects
// the only thing we need to do is replacing Boolean type with our desired type

// reading arrays

Boolean[] value = prefser.get("key", Boolean[].class, new Boolean[]{});
Float[] value = prefser.get("key", Float[].class, new Float[]{});
Integer[] value = prefser.get("key", Integer[].class, new Integer[]{});
Long[] value = prefser.get("key", Long[].class, new Long[]{});
Double[] value = prefser.get("key", Double[].class, new Double[]{});
String[] value = prefser.get("key", String[].class, new String[]{});
CustomObject[] value = prefser.get("key", CustomObject[].class, new CustomObject[]{});

// reading sets

Set<String> value = prefser.getPreferences().getStringSet("key", new HashSet<>()); // accessing set of strings in a "classical way"
Set<Double> value = prefser.get("key", Set.class, new HashSet<>());

observe method

You can observe changes of data with the following RxJava Observable:

<T> Observable<T> observe(String key, Class<T> classOfT, T defaultValue)

or with TypeToken (e.g when observing Lists):

<T> Observable<T> observe(String key, TypeToken<T> typeTokenOfT, T defaultValue)

Note

Use it, when you want to observe single preference under a specified key. When you want to observe many preferences, use observePreferences() method.

Example

Disposable subscription = prefser.observe(key, String.class, "default value")
  .subscribeOn(Schedulers.io())
  ... // you can do anything else, what is possible with RxJava
  .observeOn(AndroidSchedulers.mainThread())
  .subscribe(new Consumer<String>() {
    @Override public void accept(@NonNull String value) {
    // Perform any action you want.
    // E.g. display value in a TextView.
   }
});

getAndObserve method

You can combine functionality of get(...) and observe(...) methods with getAndObserve(...), which is defined as follows:

<T> Observable<T> getAndObserve(String key, Class<T> classOfT, T defaultValue)

or with TypeToken (e.g. when observing Lists):

<T> Observable<T> getAnd

Prefser

Install / Use

README

Prefser

Contents

Overview

Creating Prefser object

Saving data

Reading data

get method

observe method

getAndObserve method