Android-Live-Shared-Preferences-Gist6

MultiPreference.kt

class MultiPreference<T> constructor(private val updates: Observable<String>,
                                     private val preferences: SharedPreferences,
                                     private val keys: List<String>,
                                     private val defaultValue: T) : MutableLiveData<Map<String, T>>() {

    private var disposable: Disposable? = null
    private val values = mutableMapOf<String, T>()

    init {
        for (key in keys)
            values[key] = preferences.all[key] as T ?: defaultValue
    }

    override fun onActive() {
        super.onActive()
        value = values

        disposable = updates.filter { t -> keys.contains(t) }.subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread()).subscribeWith(object: DisposableObserver<String>() {
                override fun onComplete() {

                }

                override fun onNext(t: String) {
                    values[t] = preferences.all[t] as T ?: defaultValue
                    postValue(values)
                }

                override fun onError(e: Throwable) {

                }
            })
    }

    override fun onInactive() {
        super.onInactive()
        disposable?.dispose()
    }
}