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package ca.allanwang.kau.kpref
import ca.allanwang.kau.kotlin.ILazyResettable
/**
* Created by Allan Wang on 2017-06-07.
*/
fun KPref.kprefSingle(key: String) = KPrefSingleDelegate(key, this)
/**
* Singular KPref Delegate for booleans
* When the shared pref is not initialized, it will return true then set the pref to false
* All subsequent retrievals will be false
* This is useful for one time toggles such as showcasing items
*/
class KPrefSingleDelegate internal constructor(private val key: String, private val pref: KPref, lock: Any? = null) : ILazyResettable<Boolean> {
@Volatile private var _value: Boolean? = null
private val lock = lock ?: this
init {
if (pref.prefMap.containsKey(key))
throw KPrefException("$key is already used elsewhere in preference ${pref.PREFERENCE_NAME}")
pref.prefMap.put(key, this@KPrefSingleDelegate)
}
override fun invalidate() {
_value = null
}
override val value: Boolean
get() {
val _v1 = _value
if (_v1 != null)
return _v1
return synchronized(lock) {
val _v2 = _value
if (_v2 != null) {
_v2
} else {
_value = pref.sp.getBoolean(key, true)
if (_value!!) pref.sp.edit().putBoolean(key, false).apply()
_value!!
}
}
}
override fun isInitialized(): Boolean = _value != null
override fun toString(): String = if (isInitialized()) value.toString() else "Lazy kPref $key not initialized yet."
}
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