README.md

LazyThreeTenBp

A lazy loading ZoneRuleProvider for ThreeTenBp.

Usage

You have to initialize LazyThreeTenBp as early as possible, before your code accesses any threetenbp class. Usually the best place is in your Application.onCreate() method:

override fun onCreate() {
    super.onCreate()
    LazyThreeTen.init(this)
}

Afterwards you can call LazyThreeTen.cacheZones() on a background thread to cache the timezone information without blocking the startup of your app. If you decide not to do that the individual timezones will be loaded on demand when they are accessed for the first time.

Download

Add a Gradle dependency:

implementation "org.threeten:threetenbp:1.6.0:no-tzdb"
implementation "com.github.usefulness:lazythreetenbp:${version}"

Changes

Compiler

• generate java code for list of all timezone ids
• generate a separate .dat file for each zone
• only support one timezone data version at a time (makes some things easier)

Runtime

• custom ZoneRulesProvider
• provides generated timezone id list
• only reads timezone from assets/disk when that timezone was requested

Update tzdb data

1. Check for the latest tzdb version at https://www.iana.org/time-zones
2. Run ./gradlew generateLazyZoneRules -Plazythreetenbp.tzdbVersion=VERSION