PreferenceHelper

A powerful, painless way to utilize SharedPreferences.

Getting Started

Add it in your root build.gradle at the end of repositories:

allprojects {
    repositories {
        maven { url 'https://jitpack.io' }
    }
}

Add the following to the dependencies section of app/build.gradle (check Releases for the latest version):

implementation 'com.github.simplymadeapps:PreferenceHelper:2.0.0'

Usage

Initialize

Init the library in the Application.onCreate() method. You can also put this at that top of your start activity's onCreate(). All that matters is init() is called before any other calls to the PreferenceHelper.

public class MyApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        PreferenceHelper.init(this);
    }
}

Get/Set

Now that the library has been initialized, you can easily use put() and get().

Storing an object:

PreferenceHelper.put("current_user_name", "John Doe");

Getting an object:

String username = PreferenceHelper.get("current_user_name", "No Name");

Handling nulls

The library is using the object type of the input or fallback to determine what SharedPreference method to use (ex, putString, putLong, putInt, etc). This can cause confusion when you pass in a null object as one of these parameters. If you need to store a null object or retrieve an object with a null fallback you should pass in that object type.

Storing a null string:

PreferenceHelper.put("current_user_name", null, String.class);

Getting a set with a null fallback:

Set<String> usernames = PreferenceHelper.get("all_names", null, Set.class);

Note that primitive types (int, boolean, float, long) cannot be null.

Contains

You can also check if a value has been stored with:

boolean key_exists = PreferenceHelper.contains("some_key");

Removing

You can remove an object at a key with:

PreferenceHelper.remove("some_key");

Custom Objects

The PreferenceHelper can also store non-primitive objects. Your object will be serialized and stored as a JSON string.

PreferenceHelper.put("current_user", user);
User user = PreferenceHelper.get("current_user", null, User.class);

Custom Objects with Type Parameters

Due to type erasure at compile time, the library will not know what type parameter type to convert the objects to when deserializing. For example, retrieving something like HashMap<String, String> will not work properly as it will return you a generic HashMap object with unknown type params.

The only object with type params that the library will handle properly is List objects. Use getList() and putList() instead of the regular get() and put().

// Store the list
List<User> userList = new ArrayList<>();
PreferenceHelper.putList("list_key", userList);

// Retrieve the list
List<User> fallbackList = new ArrayList<>();
List<User> userList = PreferenceHelper.getList("list_key", fallbackList, User[].class);

This will look up the object array stored at that key and turn it into a List of that object type. If nothing is stored, the fallback will be returned. If a null value is stored, a null list will be returned. If the stored object at the specified key is not a valid array or list of the desired object, an exception will be thrown.

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request

License

The library is available as open source under the terms of the MIT License.