Prefs delegates

Yet one more library leveraging kotlin magic for elegant shared prefs handling. With some extra rx sugar on top.

Features

• Handles all primitive types that Shared Preferences do.
• ...but adds hassle-free enum serialization.
• ...and any arbitrary Serializable structure via moshi json serializer.
• Takes care of proper handling of nullable and default values.
• Provides RxJava observability.

Usage

Basic usage

You can use the delegates directly like you would use a regular variable:

var someFlag by prefs.boolean("some_flag", false)

textView.text = "The flag is currently: $someFlag" //loaded from shared preferences

someFlag = true //saved to shared preferences

The magic part is that every time you read or write the variable, it's loaded from shared prefs or saved to them.

Nullability and default values

var booleanImplicit by prefs.boolean("key1", false)
var booleanExplicit: Boolean by prefs.boolean("key2", false)
var booleanNullableImplicit by prefs.boolean("key3")
var booleanNullableExplicit: Boolean? by prefs.boolean("key4")
var booleanNullableExplicitDefault: Boolean? by prefs.boolean("key5", false)

Observable

val someObservableInt = prefs.observableInt("some_observable_int")

someObservableInt.observable().subscribe {
    //will return the current value from shared prefs upon subscription
    //and then while it's subscribed, every value subsequently written to it.
}

//for the observable to work you need to save via the same instance
someObservableInt.save(21)

Supported classes

• Boolean
• Int
• Long
• Float
• Double
• String
• StringSet
• Enum (saved as a string name of the enum)
• and other classes that can be serialized to json via moshi

NOTE Prefer moshi-codegen for json serialization. Reflection is much slower and deserializing large structures upon app startup may slow it down significantly.

Installation

Add it in your root build.gradle at the end of repositories:

allprojects {
    repositories {
        maven { url 'https://jitpack.io' }
    }
}

Add the dependency with current JitPack version:

dependencies {
    implementation 'com.github.FutureMind:prefs-delegates:0.10.0'
    
    // or if you need only one of the library modules:
    implementation 'com.github.FutureMind.prefs-delegates:preferencesdelegates:0.10.0'
    implementation 'com.github.FutureMind.prefs-delegates:rxpreferencesdelegates:0.10.0'
}