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Diffstat (limited to 'src/main/java/at/bitfire/ical4android/AndroidCompatTimeZoneRegistry.kt')
| -rw-r--r-- | src/main/java/at/bitfire/ical4android/AndroidCompatTimeZoneRegistry.kt | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/src/main/java/at/bitfire/ical4android/AndroidCompatTimeZoneRegistry.kt b/src/main/java/at/bitfire/ical4android/AndroidCompatTimeZoneRegistry.kt new file mode 100644 index 0000000..5f7246d --- /dev/null +++ b/src/main/java/at/bitfire/ical4android/AndroidCompatTimeZoneRegistry.kt @@ -0,0 +1,83 @@ +package at.bitfire.ical4android + +import net.fortuna.ical4j.model.* +import net.fortuna.ical4j.model.component.VTimeZone +import net.fortuna.ical4j.model.property.TzId +import java.time.ZoneId + +/** + * The purpose of this class is that if a time zone has a different name in ical4j and Android, + * it should use the Android name. + * + * For instance, if a time zone is known as "Europe/Kyiv" (with alias "Europe/Kiev") in ical4j + * and only "Europe/Kiev" in Android, this registry behaves like the default [TimeZoneRegistryImpl], + * but the returned time zone for `getTimeZone("Europe/Kiev")` has an ID of "Europe/Kiev" and not + * "Europe/Kyiv". + */ +class AndroidCompatTimeZoneRegistry( + private val base: TimeZoneRegistry +): TimeZoneRegistry by base { + + /** + * Gets the time zone for a given ID. + * + * If a time zone with the given ID exists in Android, the icalj timezone for this ID + * is returned, but the TZID is set to the Android name (and not the ical4j name, which + * may not be known to Android). + * + * If a time zone with the given ID doesn't exist in Android, this method returns the + * result of its [base] method. + * + * @param id + * @return time zone + */ + override fun getTimeZone(id: String): TimeZone? { + // check whether time zone is available on Android + val androidTzId = + try { + ZoneId.of(id).id + } catch (e: Exception) { + /* Not available in Android, should return null in a later version. + However, we return the ical4j timezone to keep the changes caused by AndroidCompatTimeZoneRegistry introduction + as small as possible. */ + return base.getTimeZone(id) + } + + /* Time zone known by Android. Unfortunately, we can't use the Android timezone database directly + to generate ical4j timezone definitions (which are based on VTIMEZONE). + So we have to use the timezone definition from ical4j (based on its own VTIMEZONE database), + but we also need to use the Android TZ name (otherwise Android may not understand it later). + + Example: getTimeZone("Europe/Kiev") returns a TimeZone with TZID:Europe/Kyiv since ical4j/3.2.5, + but most Android devices don't now Europe/Kyiv yet. + */ + val tz = base.getTimeZone(id) + if (tz.id != androidTzId) { + Ical4Android.log.warning("Using Android TZID $androidTzId instead of ical4j ${tz.id}") + + // create a copy of the VTIMEZONE so that we don't modify the original registry values (which are not immutable) + val vTimeZone = tz.vTimeZone + val newVTimeZoneProperties = PropertyList(vTimeZone.properties) + newVTimeZoneProperties.removeAll { property -> + property is TzId + } + newVTimeZoneProperties += TzId(androidTzId) + return TimeZone(VTimeZone( + newVTimeZoneProperties, + vTimeZone.observances + )) + } else + return tz + } + + + class Factory : TimeZoneRegistryFactory() { + + override fun createRegistry(): TimeZoneRegistry { + val ical4jRegistry = DefaultTimeZoneRegistryFactory().createRegistry() + return AndroidCompatTimeZoneRegistry(ical4jRegistry) + } + + } + +}
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