Kotpref

Android SharedPreference delegation for Kotlin.

Important

Kotpref is no longer maintained. Development has ended and this repository is archived: there will be no further releases, and issues and pull requests are no longer accepted.

Use Jetpack DataStore instead — see the migration guide.

Existing builds are unaffected. All published artifacts remain on Maven Central and will not be removed, so there is no rush to migrate. The Install and How to use sections below stay in place as a reference for current users.

For most Kotpref models, Preferences DataStore is the direct replacement: the same key-value storage, with an asynchronous, observable API that SharedPreferences never had. Proto DataStore is worth a look as well — Kotpref existed largely to give a group of preferences the shape of a typed object, and Proto DataStore does that natively, with a real schema instead of loose keys. Community libraries offering a delegate-style API on top of DataStore also exist, if that is what you liked about Kotpref.

Thanks to everyone who used Kotpref and contributed to it over the years.

Install

repositories {
    mavenCentral()
}

dependencies {
    // core
    implementation 'com.chibatching.kotpref:kotpref:2.13.2'
  
    // optional, auto initialization module
    implementation 'com.chibatching.kotpref:initializer:2.13.2'
  
    // optional, support saving enum value and ordinal
    implementation 'com.chibatching.kotpref:enum-support:2.13.2'
  
    // optional, support saving json string through Gson
    implementation 'com.chibatching.kotpref:gson-support:2.13.2'
    implementation 'com.google.code.gson:gson:2.8.6'
  
    // optional, support LiveData observable preference
    implementation 'com.chibatching.kotpref:livedata-support:2.13.2'
    implementation 'androidx.lifecycle:lifecycle-livedata:2.2.0'

    // experimental, preference screen build dsl
    implementation 'com.chibatching.kotpref:preference-screen-dsl:2.13.2'
}

How to use

Declare preference model

object UserInfo : KotprefModel() {
    var name by stringPref()
    var code by nullableStringPref()
    var age by intPref(default = 14)
    var highScore by longPref()
    var rate by floatPref()
    val prizes by stringSetPref {
        val set = TreeSet<String>()
        set.add("Beginner")
        return@stringSetPref set
    }
}

enum class GameLevel {
    EASY,
    NORMAL,
    HARD
}

Set up

Pass the application context to Kotpref

Kotpref.init(context)

or use auto initializer module.

Injectable Context

If you don't want to use singleton context because of unit test or etc.., you can use secondary constructor of KotprefModel to inject context.

class InjectableContextSamplePref(context: Context) : KotprefModel(context) {
    var sampleData by stringPref()
}

If you set context to all your model, you don't need call Kotpref.init(context) and don't use auto initializer module.

Read and Write

UserInfo.gameLevel = GameLevel.HARD
UserInfo.name = "chibatching"
UserInfo.code = "DAEF2599-7FC9-49C5-9A11-3C12B14A6898"
UserInfo.age = 30
UserInfo.highScore = 49219902
UserInfo.rate = 49.21F
UserInfo.prizes.add("Bronze")
UserInfo.prizes.add("Silver")
UserInfo.prizes.add("Gold")

Log.d(TAG, "Game level: ${UserInfo.gameLevel}")
Log.d(TAG, "User name: ${UserInfo.name}")
Log.d(TAG, "User code: ${UserInfo.code}")
Log.d(TAG, "User age: ${UserInfo.age}")
Log.d(TAG, "User high score: ${UserInfo.highScore}")
Log.d(TAG, "User rate: ${UserInfo.rate}")
UserInfo.prizes.forEachIndexed { i, s -> Log.d(TAG, "prize[$i]: $s") }

Bulk edit

UserInfo.bulk {
    gameLevel = GameLevel.EASY
    name = "chibatching Jr"
    code = "451B65F6-EF95-4C2C-AE76-D34535F51B3B"
    age = 2
    highScore = 3901
    rate = 0.4F
    prizes.clear()
    prizes.add("New Born")
}

// Bulk edit uses Editor#apply() method internally.
// If you want to apply immediately, you can use blockingBulk instead.
UserInfo.blockingBulk {
    gameLevel = GameLevel.EASY
}

Result shared preference xml

XML file name equals model class name. If model class named UserInfo, XML file name is UserInfo.xml.

<?xml version='1.0' encoding='utf-8' standalone='yes' ?>
<map>
    <long name="highScore" value="49219902" />
    <set name="prizes">
        <string>Beginner</string>
        <string>Bronze</string>
        <string>Gold</string>
        <string>Silver</string>
    </set>
    <string name="name">chibatching</string>
    <string name="code">DAEF2599-7FC9-49C5-9A11-3C12B14A6898</string>
    <int name="age" value="30" />
    <float name="rate" value="49.21" />
</map>

Options

Change default value

var age: Int by intPref(18)

or

var age: Int by intPref(default = 18)

Change preference key

You can custom preference key or use from string resources.

var useFunc1: Boolean by booleanPref(key = "use_func1")
var mode: Int by intPref(default = 1, key = R.string.pref_mode)

Change default save mode

Kotpref save all preference property by apply method. You can change method to commit for each property.

var age: Int by intPref(default = 18, commitByDefault = true)

Or change default for each KotprefModel.

object UserInfo : KotprefModel() {
    override val commitAllPropertiesByDefault: Boolean = true

Change XML file name

Override kotprefName property.

object UserInfo : KotprefModel() {
    override val kotprefName: String = "user_info"

Change SharedPreference mode

Override kotprefMode property. Default is Context.MODE_PRIVATE.

object UserInfo : KotprefModel() {
    override val kotprefMode: Int = Context.MODE_MULTI_PROCESS

API Docs

https://chibatching.github.io/Kotpref/docs/api/-modules.html

License

Copyright 2015-2021 Takao Chiba

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.