LiveData

The livedata library adds extension functions to convert the Prefrence into LiveData and Observer objects.

Getting the Dependency

implementation "com.frybits.rx.preferences:livedata:2.0.1"

Usage

Preference as LiveData

Kotlin Java

val rxSharedPreferences = sharedPreferences.asRxSharedPreferences()

val usernamePref: Preference<String?> = rxSharedPreferences.getString("username")

val usernameLiveData: LiveData<String?> = usernamePref.asLiveData()

usernameLiveData.observeForever { name ->
    println(name) // Immediately emits 'null'
}

usernamePref.value = "bob"
// Output from livedata => "bob"

RxSharedPreferences rxSharedPreferences = RxSharedPreferences.create(sharedPreferences);

Preference<String> usernamePref = rxSharedPreferences.getString("username");

LiveData<String> usernameLiveData = LiveDataPreference.asLiveData(usernamePref);

usernameLiveData.observeForever(s -> {
    System.out.println(s); // Immediately emits 'null'
});

usernamePref.setValue("bob");
// Output from livedata => "bob"

Preferene as an Observer

Kotlin Java

val rxSharedPreferences = sharedPreferences.asRxSharedPreferences()

val featureEnabledPref: Preference<Boolean> = rxSharedPreferences.getBoolean("somePref")

val featureEnabledObserver = featureEnabledPref.asObserver()

val checkButtonLiveData = object : LiveData<Boolean>() {

    val onChangedListener = OnCheckedChangeListener { _, isChecked ->
        value = isChecked
    }

    override fun onActive() {
        button.setOnCheckedChangeListener(onChangedListener)
    }

    override fun onInactive() {
        button.setOnCheckedChangeListener(null)
    }
}

checkButtonLiveData.observeForever(featureEnabledObserver)

RxSharedPreferences rxSharedPreferences = RxSharedPreferences.create(sharedPreferences);

Preference<Boolean> featureEnabledPref = rxSharedPreferences.getBoolean("somePref");

Observer<Boolean> featureEnabledObserver = LiveDataPreference.asObserver(featureEnabledPref);

LiveData<Boolean> checkButtonLiveData = new LiveData<>() {

    private OnCheckedChangeListener onChangedListener = new OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            setValue(isChecked);
        }
    };

    @Override
    public void onActive() {
        button.setOnCheckedChangeListener(onChangedListener);
    }

    @Override
    public void onInactive() {
        button.setOnCheckedChangeListener(null);
    }
};

checkButtonLiveData.observeForever(featureEnabledObserver);