Kreference

Preference as Properties for Kotlin Android.

Installation

Add this line to your build.gradle

compile "com.github.verachadw:kreference:0.8.0"

Features

• One line Preference item declaration
• Null-Safety
• Allow default value for preference item
• Support traditional style to get/set preference item. This is useful when Context is not available at class initialization
• Support Non-Primitive type e.g. Date

Overview

When you want to get/set a String in SharedPreference in Android. You need this bunch of code

    object PreferenceHelper {
        fun getMyPrefString(context: Context): String? {
            val preference = context.getSharedPreferences("myPref", Context.MODE_PRIVATE)
            return preference.getString("myString")
        }

        fun setMyPrefString(context: Context, newString) {
            val preference = context.getSharedPreferences("myPref", Context.MODE_PRIVATE)
            val editor = preference.edit()
            editor.putString("myString", new String)
            editor.apply()
        }
    }

    // Get value in Activity
    PreferenceHelper.getMyPrefString(this)
    // Set value in Activity
    PreferenceHelper.setMyPrefString(this, "This is not simple :(")

A lot of work just to handle 1 item. Is it better if you can write those stuff as one-liner, or even better as a property in class? Kreference make that happen for you. Here is how we declare myString with Kreference.

    // Declare in Activity. No need for additional class.
    private val myString by Kreference.asString(this)
    ...
    // Use it as same as variable in activity
    textView.setText(myString)
    myString = "This is simple and lovely :)"

Since Kreference used the variable's name as a key of preference item, You can easily access preference item in different classes by using the same variable name.

    object MyPref1 {
       val myTime by Kreference.asLong(this)
    }

    object MyPref2 {
       val myTime by Kreference.asLong(this)
    }

   // This is true
    MyPref1.myTime == MyPref2.myTime

From some usecases, we want to use Kreference, but the Context object cannot be accessible during class initialization( e.g. BoardCastReceiver). Since we cannot decalre properties as local variable, Kreference provide get/set methods to obtain preference item easily. Here are some example.

    //Getter
    Kreference.get<String>(context, "myString", "default-value")
    
    //Setter
    Kreference.set<String>(context, "myString", "new-value")
    

Need more features?

Create an issue or send PR to me.

Licensce

The MIT License (MIT)

Copyright (c) 2015 Verachad Wongsawangtham

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.