使用委托类实现简化SharedPreference的使用

PreDelegate.kt

class PreDelegate<T>(
    private val name: String,
    private val default: T,
    private val isCommit: Boolean = false,
    private val prefs: SharedPreferences
) {

    operator fun getValue(thisRef: Any?, property: KProperty<*>): T {
        return getPref(name, default) ?: default
    }

    operator fun setValue(thisRef: Any?, property: KProperty<*>, value: T) {
        value?.let {
            putPref(name, value)
        }
    }

    private fun <T> getPref(name: String, defalut: T?) = with(prefs) {
        val result: Any? = when (defalut) {
            is Long -> getLong(name, defalut)
            is String -> getString(name, defalut)
            is Int -> getInt(name, defalut)
            is Boolean -> getBoolean(name, defalut)
            is Float -> getFloat(name, defalut)
            else -> throw IllegalArgumentException("This type is not supported")
        }
        result as? T
    }

    private fun <T> putPref(name: String, value: T) = with(prefs.edit()) {
        when (value) {
            is Long -> putLong(name, value)
            is String -> putString(name, value)
            is Int -> putInt(name, value)
            is Boolean -> putBoolean(name, value)
            is Float -> putFloat(name, value)
            else -> throw IllegalArgumentException("This type is not supported")
        }
        if (isCommit) {
            commit()
        } else {
            apply()
        }
    }
}