benigumocom · January 14, 2021 03:02 · Oct 25, 2018 · Sep 14, 2018 · May 9, 2017 · May 5, 2017
diff --git a/Preferences.kt b/Preferences.kt
@@ -14,6 +14,9 @@ import kotlin.reflect.KProperty
  * }
  * ```
  */
+// Ignore unused warning. This class needs to handle all data types, regardless of whether the method is used.
+// Allow unchecked casts - we can blindly trust that data we read is the same type we saved it as..
+@Suppress("UNCHECKED_CAST", "unused")
 abstract class Preferences(private var context: Context, private val name: String? = null) {
     private val prefs: SharedPreferences by lazy {
         context.getSharedPreferences(name ?: javaClass.simpleName, Context.MODE_PRIVATE)
@@ -22,7 +25,6 @@ abstract class Preferences(private var context: Context, private val name: Strin
     private val listeners = mutableListOf<SharedPrefsListener>()
 
     abstract class PrefDelegate<T>(val prefKey: String?) {
-
         abstract operator fun getValue(thisRef: Any?, property: KProperty<*>): T
         abstract operator fun setValue(thisRef: Any?, property: KProperty<*>, value: T)
     }
@@ -41,85 +43,81 @@ abstract class Preferences(private var context: Context, private val name: Strin
 
     fun clearListeners() = listeners.clear()
 
-    fun stringPref(prefKey: String? = null, defaultValue: String? = null) = StringPrefDelegate(prefKey, defaultValue)
-
-    inner class StringPrefDelegate(prefKey: String? = null, val defaultValue: String?) :
-        PrefDelegate<String?>(prefKey) {
-        override fun getValue(thisRef: Any?, property: KProperty<*>): String? =
-            prefs.getString(prefKey ?: property.name, defaultValue)
-
-        override fun setValue(thisRef: Any?, property: KProperty<*>, value: String?) {
-            prefs.edit().putString(prefKey ?: property.name, value).apply()
-            onPrefChanged(property)
-        }
+    enum class StorableType {
+        String,
+        Int,
+        Float,
+        Boolean,
+        Long,
+        StringSet
     }
 
-    fun intPref(prefKey: String? = null, defaultValue: Int = 0) = IntPrefDelegate(prefKey, defaultValue)
-
-    inner class IntPrefDelegate(prefKey: String? = null, val defaultValue: Int) : PrefDelegate<Int>(prefKey) {
-        override fun getValue(thisRef: Any?, property: KProperty<*>) =
-            prefs.getInt(prefKey ?: property.name, defaultValue)
-
-        override fun setValue(thisRef: Any?, property: KProperty<*>, value: Int) {
-            prefs.edit().putInt(prefKey ?: property.name, value).apply()
-            onPrefChanged(property)
+    inner class GenericPrefDelegate<T>(prefKey: String? = null, private val defaultValue: T?, val type: StorableType) :
+        PrefDelegate<T?>(prefKey) {
+        override fun getValue(thisRef: Any?, property: KProperty<*>): T? =
+            when (type) {
+                StorableType.String ->
+                    prefs.getString(prefKey ?: property.name, defaultValue as String?) as T?
+                StorableType.Int ->
+                    prefs.getInt(prefKey ?: property.name, defaultValue as Int) as T?
+                StorableType.Float ->
+                    prefs.getFloat(prefKey ?: property.name, defaultValue as Float) as T?
+                StorableType.Boolean ->
+                    prefs.getBoolean(prefKey ?: property.name, defaultValue as Boolean) as T?
+                StorableType.Long ->
+                    prefs.getLong(prefKey ?: property.name, defaultValue as Long) as T?
+                StorableType.StringSet ->
+                    prefs.getStringSet(prefKey ?: property.name, defaultValue as Set<String>) as T?
+            }
+
+        override fun setValue(thisRef: Any?, property: KProperty<*>, value: T?) {
+            when (type) {
+                StorableType.String -> {
+                    prefs.edit().putString(prefKey ?: property.name, value as String?).apply()
+                    onPrefChanged(property)
+                }
+                StorableType.Int -> {
+                    prefs.edit().putInt(prefKey ?: property.name, value as Int).apply()
+                    onPrefChanged(property)
+                }
+                StorableType.Float -> {
+                    prefs.edit().putFloat(prefKey ?: property.name, value as Float).apply()
+                    onPrefChanged(property)
+                }
+                StorableType.Boolean -> {
+                    prefs.edit().putBoolean(prefKey ?: property.name, value as Boolean).apply()
+                    onPrefChanged(property)
+                }
+                StorableType.Long -> {
+                    prefs.edit().putLong(prefKey ?: property.name, value as Long).apply()
+                    onPrefChanged(property)
+                }
+                StorableType.StringSet -> {
+                    prefs.edit().putStringSet(prefKey ?: property.name, value as Set<String>).apply()
+                    onPrefChanged(property)
+                }
+            }
         }
-    }
-
-
-    fun floatPref(prefKey: String? = null, defaultValue: Float = 0f) = FloatPrefDelegate(prefKey, defaultValue)
 
-    inner class FloatPrefDelegate(prefKey: String? = null, val defaultValue: Float) : PrefDelegate<Float>(prefKey) {
-        override fun getValue(thisRef: Any?, property: KProperty<*>) =
-            prefs.getFloat(prefKey ?: property.name, defaultValue)
-
-        override fun setValue(thisRef: Any?, property: KProperty<*>, value: Float) {
-            prefs.edit().putFloat(prefKey ?: property.name, value).apply()
-            onPrefChanged(property)
-        }
     }
 
+    fun stringPref(prefKey: String? = null, defaultValue: String? = null) =
+        GenericPrefDelegate(prefKey, defaultValue, StorableType.String)
 
-    fun booleanPref(prefKey: String? = null, defaultValue: Boolean = false) = BooleanPrefDelegate(prefKey, defaultValue)
+    fun intPref(prefKey: String? = null, defaultValue: Int = 0) =
+        GenericPrefDelegate(prefKey, defaultValue, StorableType.Int)
 
-    inner class BooleanPrefDelegate(prefKey: String? = null, val defaultValue: Boolean) :
-        PrefDelegate<Boolean>(prefKey) {
-        override fun getValue(thisRef: Any?, property: KProperty<*>) =
-            prefs.getBoolean(prefKey ?: property.name, defaultValue)
+    fun floatPref(prefKey: String? = null, defaultValue: Float = 0f) =
+        GenericPrefDelegate(prefKey, defaultValue, StorableType.Float)
 
-        override fun setValue(thisRef: Any?, property: KProperty<*>, value: Boolean) {
-            prefs.edit().putBoolean(prefKey ?: property.name, value).apply()
-            onPrefChanged(property)
-        }
-    }
-
-
-    fun longPref(prefKey: String? = null, defaultValue: Long = 0L) = LongPrefDelegate(prefKey, defaultValue)
+    fun booleanPref(prefKey: String? = null, defaultValue: Boolean = false) =
+        GenericPrefDelegate(prefKey, defaultValue, StorableType.Boolean)
 
-    inner class LongPrefDelegate(prefKey: String? = null, val defaultValue: Long) : PrefDelegate<Long>(prefKey) {
-        override fun getValue(thisRef: Any?, property: KProperty<*>) =
-            prefs.getLong(prefKey ?: property.name, defaultValue)
-
-        override fun setValue(thisRef: Any?, property: KProperty<*>, value: Long) {
-            prefs.edit().putLong(prefKey ?: property.name, value).apply()
-            onPrefChanged(property)
-        }
-    }
+    fun longPref(prefKey: String? = null, defaultValue: Long = 0L) =
+        GenericPrefDelegate(prefKey, defaultValue, StorableType.Long)
 
-
-    fun stringSetPref(prefKey: String? = null, defaultValue: Set<String> = HashSet<String>()) =
-        StringSetPrefDelegate(prefKey, defaultValue)
-
-    inner class StringSetPrefDelegate(prefKey: String? = null, val defaultValue: Set<String>) :
-        PrefDelegate<Set<String>>(prefKey) {
-        override fun getValue(thisRef: Any?, property: KProperty<*>): Set<String> =
-            prefs.getStringSet(prefKey ?: property.name, defaultValue)
-
-        override fun setValue(thisRef: Any?, property: KProperty<*>, value: Set<String>) {
-            prefs.edit().putStringSet(prefKey ?: property.name, value).apply()
-            onPrefChanged(property)
-        }
-    }
+    fun stringSetPref(prefKey: String? = null, defaultValue: Set<String> = HashSet()) =
+        GenericPrefDelegate(prefKey, defaultValue, StorableType.StringSet)
 
     private fun onPrefChanged(property: KProperty<*>) {
         listeners.forEach { it.onSharedPrefChanged(property) }

diff --git a/Preferences.kt b/Preferences.kt
@@ -1,4 +1,3 @@
-
 import android.content.Context
 import android.content.SharedPreferences
 import kotlin.reflect.KProperty
@@ -8,41 +7,22 @@ import kotlin.reflect.KProperty
  *
  * Usage:
  *
- * `Preferences.init(context)`
- *
  * ```kotlin
  * class UserPreferences : Preferences() {
  *   var emailAccount by stringPref()
  *   var showSystemAppsPreference by booleanPref()
  * }
  * ```
  */
-abstract class Preferences {
-    companion object {
-        private var context: Context? = null
-
-        /**
-         * Initialize PrefDelegate with a Context reference.
-         *
-         * **This method needs to be called before any other usage of PrefDelegate!!**
-         */
-        fun init(context: Context) {
-            this.context = context
-        }
-    }
-
+abstract class Preferences(private var context: Context, private val name: String? = null) {
     private val prefs: SharedPreferences by lazy {
-        if (context != null)
-            context!!.getSharedPreferences(javaClass.simpleName, Context.MODE_PRIVATE)
-        else
-            throw IllegalStateException("Context was not initialized. Call Preferences.init(context) before using it")
+        context.getSharedPreferences(name ?: javaClass.simpleName, Context.MODE_PRIVATE)
     }
 
     private val listeners = mutableListOf<SharedPrefsListener>()
 
     abstract class PrefDelegate<T>(val prefKey: String?) {
 
-
         abstract operator fun getValue(thisRef: Any?, property: KProperty<*>): T
         abstract operator fun setValue(thisRef: Any?, property: KProperty<*>, value: T)
     }
@@ -63,8 +43,11 @@ abstract class Preferences {
 
     fun stringPref(prefKey: String? = null, defaultValue: String? = null) = StringPrefDelegate(prefKey, defaultValue)
 
-    inner class StringPrefDelegate(prefKey: String? = null, val defaultValue: String?) : PrefDelegate<String?>(prefKey) {
-        override fun getValue(thisRef: Any?, property: KProperty<*>): String? = prefs.getString(prefKey ?: property.name, defaultValue)
+    inner class StringPrefDelegate(prefKey: String? = null, val defaultValue: String?) :
+        PrefDelegate<String?>(prefKey) {
+        override fun getValue(thisRef: Any?, property: KProperty<*>): String? =
+            prefs.getString(prefKey ?: property.name, defaultValue)
+
         override fun setValue(thisRef: Any?, property: KProperty<*>, value: String?) {
             prefs.edit().putString(prefKey ?: property.name, value).apply()
             onPrefChanged(property)
@@ -74,7 +57,9 @@ abstract class Preferences {
     fun intPref(prefKey: String? = null, defaultValue: Int = 0) = IntPrefDelegate(prefKey, defaultValue)
 
     inner class IntPrefDelegate(prefKey: String? = null, val defaultValue: Int) : PrefDelegate<Int>(prefKey) {
-        override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getInt(prefKey ?: property.name, defaultValue)
+        override fun getValue(thisRef: Any?, property: KProperty<*>) =
+            prefs.getInt(prefKey ?: property.name, defaultValue)
+
         override fun setValue(thisRef: Any?, property: KProperty<*>, value: Int) {
             prefs.edit().putInt(prefKey ?: property.name, value).apply()
             onPrefChanged(property)
@@ -85,7 +70,9 @@ abstract class Preferences {
     fun floatPref(prefKey: String? = null, defaultValue: Float = 0f) = FloatPrefDelegate(prefKey, defaultValue)
 
     inner class FloatPrefDelegate(prefKey: String? = null, val defaultValue: Float) : PrefDelegate<Float>(prefKey) {
-        override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getFloat(prefKey ?: property.name, defaultValue)
+        override fun getValue(thisRef: Any?, property: KProperty<*>) =
+            prefs.getFloat(prefKey ?: property.name, defaultValue)
+
         override fun setValue(thisRef: Any?, property: KProperty<*>, value: Float) {
             prefs.edit().putFloat(prefKey ?: property.name, value).apply()
             onPrefChanged(property)
@@ -95,8 +82,11 @@ abstract class Preferences {
 
     fun booleanPref(prefKey: String? = null, defaultValue: Boolean = false) = BooleanPrefDelegate(prefKey, defaultValue)
 
-    inner class BooleanPrefDelegate(prefKey: String? = null, val defaultValue: Boolean) : PrefDelegate<Boolean>(prefKey) {
-        override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getBoolean(prefKey ?: property.name, defaultValue)
+    inner class BooleanPrefDelegate(prefKey: String? = null, val defaultValue: Boolean) :
+        PrefDelegate<Boolean>(prefKey) {
+        override fun getValue(thisRef: Any?, property: KProperty<*>) =
+            prefs.getBoolean(prefKey ?: property.name, defaultValue)
+
         override fun setValue(thisRef: Any?, property: KProperty<*>, value: Boolean) {
             prefs.edit().putBoolean(prefKey ?: property.name, value).apply()
             onPrefChanged(property)
@@ -107,18 +97,24 @@ abstract class Preferences {
     fun longPref(prefKey: String? = null, defaultValue: Long = 0L) = LongPrefDelegate(prefKey, defaultValue)
 
     inner class LongPrefDelegate(prefKey: String? = null, val defaultValue: Long) : PrefDelegate<Long>(prefKey) {
-        override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getLong(prefKey ?: property.name, defaultValue)
+        override fun getValue(thisRef: Any?, property: KProperty<*>) =
+            prefs.getLong(prefKey ?: property.name, defaultValue)
+
         override fun setValue(thisRef: Any?, property: KProperty<*>, value: Long) {
             prefs.edit().putLong(prefKey ?: property.name, value).apply()
             onPrefChanged(property)
         }
     }
 
 
-    fun stringSetPref(prefKey: String? = null, defaultValue: Set<String> = HashSet<String>()) = StringSetPrefDelegate(prefKey, defaultValue)
+    fun stringSetPref(prefKey: String? = null, defaultValue: Set<String> = HashSet<String>()) =
+        StringSetPrefDelegate(prefKey, defaultValue)
+
+    inner class StringSetPrefDelegate(prefKey: String? = null, val defaultValue: Set<String>) :
+        PrefDelegate<Set<String>>(prefKey) {
+        override fun getValue(thisRef: Any?, property: KProperty<*>): Set<String> =
+            prefs.getStringSet(prefKey ?: property.name, defaultValue)
 
-    inner class StringSetPrefDelegate(prefKey: String? = null, val defaultValue: Set<String>) : PrefDelegate<Set<String>>(prefKey) {
-        override fun getValue(thisRef: Any?, property: KProperty<*>): Set<String> = prefs.getStringSet(prefKey ?: property.name, defaultValue)
         override fun setValue(thisRef: Any?, property: KProperty<*>, value: Set<String>) {
             prefs.edit().putStringSet(prefKey ?: property.name, value).apply()
             onPrefChanged(property)

diff --git a/README.md b/README.md
@@ -2,8 +2,6 @@
 
 Wrapper class for `SharedPreferences`, leveraging the awesome delegate syntax in Kotlin. 
 
-Call `Preferences.init(context)` in your `Application` class.
-
 Example preferences definition:
 
 ```kotlin

diff --git a/README.md b/README.md
@@ -0,0 +1,32 @@
+# Usage
+
+Wrapper class for `SharedPreferences`, leveraging the awesome delegate syntax in Kotlin. 
+
+Call `Preferences.init(context)` in your `Application` class.
+
+Example preferences definition:
+
+```kotlin
+class UserPreferences : Preferences() {
+ var emailAccount by stringPref()
+ var allowAnonymousLogging by booleanPref()
+}
+```
+
+Example usage:
+
+```kotlin
+preferences.allowAnonymousLogging = false
+```
+
+Example listener (not exactly the cleanest-looking but it works):
+
+```kotlin
+preferences.addListener(object : Preferences.SharedPrefsListener {
+    override fun onSharedPrefChanged(property: KProperty<*>) {
+        if (UserPreferences::allowAnonymousLogging.name == property.name) {
+            initLogging()
+        }
+    }
+})
+```
diff --git a/Preferences.kt b/Preferences.kt
@@ -64,7 +64,7 @@ abstract class Preferences {
     fun stringPref(prefKey: String? = null, defaultValue: String? = null) = StringPrefDelegate(prefKey, defaultValue)
 
     inner class StringPrefDelegate(prefKey: String? = null, val defaultValue: String?) : PrefDelegate<String?>(prefKey) {
-        override fun getValue(thisRef: Any?, property: KProperty<*>): String = prefs.getString(prefKey ?: property.name, defaultValue)
+        override fun getValue(thisRef: Any?, property: KProperty<*>): String? = prefs.getString(prefKey ?: property.name, defaultValue)
         override fun setValue(thisRef: Any?, property: KProperty<*>, value: String?) {
             prefs.edit().putString(prefKey ?: property.name, value).apply()
             onPrefChanged(property)

diff --git a/Preferences.kt b/Preferences.kt
@@ -0,0 +1,131 @@
+
+import android.content.Context
+import android.content.SharedPreferences
+import kotlin.reflect.KProperty
+
+/**
+ * Represents a single [SharedPreferences] file.
+ *
+ * Usage:
+ *
+ * `Preferences.init(context)`
+ *
+ * ```kotlin
+ * class UserPreferences : Preferences() {
+ *   var emailAccount by stringPref()
+ *   var showSystemAppsPreference by booleanPref()
+ * }
+ * ```
+ */
+abstract class Preferences {
+    companion object {
+        private var context: Context? = null
+
+        /**
+         * Initialize PrefDelegate with a Context reference.
+         *
+         * **This method needs to be called before any other usage of PrefDelegate!!**
+         */
+        fun init(context: Context) {
+            this.context = context
+        }
+    }
+
+    private val prefs: SharedPreferences by lazy {
+        if (context != null)
+            context!!.getSharedPreferences(javaClass.simpleName, Context.MODE_PRIVATE)
+        else
+            throw IllegalStateException("Context was not initialized. Call Preferences.init(context) before using it")
+    }
+
+    private val listeners = mutableListOf<SharedPrefsListener>()
+
+    abstract class PrefDelegate<T>(val prefKey: String?) {
+
+
+        abstract operator fun getValue(thisRef: Any?, property: KProperty<*>): T
+        abstract operator fun setValue(thisRef: Any?, property: KProperty<*>, value: T)
+    }
+
+    interface SharedPrefsListener {
+        fun onSharedPrefChanged(property: KProperty<*>)
+    }
+
+    fun addListener(sharedPrefsListener: SharedPrefsListener) {
+        listeners.add(sharedPrefsListener)
+    }
+
+    fun removeListener(sharedPrefsListener: SharedPrefsListener) {
+        listeners.remove(sharedPrefsListener)
+    }
+
+    fun clearListeners() = listeners.clear()
+
+    fun stringPref(prefKey: String? = null, defaultValue: String? = null) = StringPrefDelegate(prefKey, defaultValue)
+
+    inner class StringPrefDelegate(prefKey: String? = null, val defaultValue: String?) : PrefDelegate<String?>(prefKey) {
+        override fun getValue(thisRef: Any?, property: KProperty<*>): String = prefs.getString(prefKey ?: property.name, defaultValue)
+        override fun setValue(thisRef: Any?, property: KProperty<*>, value: String?) {
+            prefs.edit().putString(prefKey ?: property.name, value).apply()
+            onPrefChanged(property)
+        }
+    }
+
+    fun intPref(prefKey: String? = null, defaultValue: Int = 0) = IntPrefDelegate(prefKey, defaultValue)
+
+    inner class IntPrefDelegate(prefKey: String? = null, val defaultValue: Int) : PrefDelegate<Int>(prefKey) {
+        override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getInt(prefKey ?: property.name, defaultValue)
+        override fun setValue(thisRef: Any?, property: KProperty<*>, value: Int) {
+            prefs.edit().putInt(prefKey ?: property.name, value).apply()
+            onPrefChanged(property)
+        }
+    }
+
+
+    fun floatPref(prefKey: String? = null, defaultValue: Float = 0f) = FloatPrefDelegate(prefKey, defaultValue)
+
+    inner class FloatPrefDelegate(prefKey: String? = null, val defaultValue: Float) : PrefDelegate<Float>(prefKey) {
+        override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getFloat(prefKey ?: property.name, defaultValue)
+        override fun setValue(thisRef: Any?, property: KProperty<*>, value: Float) {
+            prefs.edit().putFloat(prefKey ?: property.name, value).apply()
+            onPrefChanged(property)
+        }
+    }
+
+
+    fun booleanPref(prefKey: String? = null, defaultValue: Boolean = false) = BooleanPrefDelegate(prefKey, defaultValue)
+
+    inner class BooleanPrefDelegate(prefKey: String? = null, val defaultValue: Boolean) : PrefDelegate<Boolean>(prefKey) {
+        override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getBoolean(prefKey ?: property.name, defaultValue)
+        override fun setValue(thisRef: Any?, property: KProperty<*>, value: Boolean) {
+            prefs.edit().putBoolean(prefKey ?: property.name, value).apply()
+            onPrefChanged(property)
+        }
+    }
+
+
+    fun longPref(prefKey: String? = null, defaultValue: Long = 0L) = LongPrefDelegate(prefKey, defaultValue)
+
+    inner class LongPrefDelegate(prefKey: String? = null, val defaultValue: Long) : PrefDelegate<Long>(prefKey) {
+        override fun getValue(thisRef: Any?, property: KProperty<*>) = prefs.getLong(prefKey ?: property.name, defaultValue)
+        override fun setValue(thisRef: Any?, property: KProperty<*>, value: Long) {
+            prefs.edit().putLong(prefKey ?: property.name, value).apply()
+            onPrefChanged(property)
+        }
+    }
+
+
+    fun stringSetPref(prefKey: String? = null, defaultValue: Set<String> = HashSet<String>()) = StringSetPrefDelegate(prefKey, defaultValue)
+
+    inner class StringSetPrefDelegate(prefKey: String? = null, val defaultValue: Set<String>) : PrefDelegate<Set<String>>(prefKey) {
+        override fun getValue(thisRef: Any?, property: KProperty<*>): Set<String> = prefs.getStringSet(prefKey ?: property.name, defaultValue)
+        override fun setValue(thisRef: Any?, property: KProperty<*>, value: Set<String>) {
+            prefs.edit().putStringSet(prefKey ?: property.name, value).apply()
+            onPrefChanged(property)
+        }
+    }
+
+    private fun onPrefChanged(property: KProperty<*>) {
+        listeners.forEach { it.onSharedPrefChanged(property) }
+    }
+}