A questionnaire may reference external information. If so, you must provide a DataCaptureConfig by implementing the DataCaptureConfig.Provider interface in your application’s [Application](https://developer.android.com/reference/android/app/Application) class. Be sure to provide the same configuration throughout your application’s lifecycle to avoid any configuration issues.
If a value set is not included as a contained resource within the questionnaire or structure map that references it, you must provide an implementation of ExternalAnswerValueSetResolver.resolve() which describes how to translate a value set’s canonical URL to the list of actual codes:
class FhirApplication : Application(), DataCaptureConfig.Provider {
private val dataCaptureConfiguration by lazy {
DataCaptureConfig(
valueSetResolverExternal =
object : ExternalAnswerValueSetResolver {
override suspend fun resolve(uri: String): List<Coding> {
return lookupCodesFromDb(uri)
}
}
)
}
override fun getDataCaptureConfig(): DataCaptureConfig {
return dataCaptureConfiguration
}
}
ExternalAnswerValueSetResolver is used for any URI that does not look like an internal reference where the URI starts with #.
FHIR resources published in FHIR Packages can be used to provide context while performing StructureMap-based data extraction.