Logging (UI Layer)#

HaapiLogger is shared across all layers — Driver, SDK, and UIKit / UIWidget — so a single configuration covers the entire stack. The UI Layer adds UI follow-up tags (HAAPI_UI_*) on top of the Driver and SDK sets. Configure it once at app startup; include every layer’s tags so you can filter to whichever subsystem is misbehaving.

For the concept (severity ordering, sensitive-value masking, custom sinks), see Logging and Observability . For the Driver and SDK layer pages, see Logging (Driver Layer) and Logging (SDK Layer) .

What the UI Layer Adds#

If you’ve already configured HaapiLogger for the SDK Layer, the only UI-specific delta is the UI follow-up tag set — tag prefixes such as HAAPI_UI_FLOW, HAAPI_UI_VIEWCONTROLLER / HAAPI_UI_FRAGMENT, HAAPI_UI_THEMING, and HAAPI_UI_DEEPLINK that identify records emitted by view controllers, fragments, theming engine, and the flow-controller / activity.

Configure UI-Layer logging when you need to:

• Diagnose theming issues — HAAPI_UI_THEMING emits warnings for missing or mistyped style keys.
• Trace screen transitions — HAAPI_UI_VIEWCONTROLLER / HAAPI_UI_FRAGMENT covers lifecycle events for each rendered step.
• Investigate deep-link delivery — HAAPI_UI_DEEPLINK shows whether the framework received an inbound deep link after an external redirect.

If your app stays at the SDK Layer (custom UI, no HaapiUIKitApplication / HaapiUIWidgetApplication), the UI follow-up tags don’t fire; skip the UI-tag wiring.

Configuration#

The pattern matches the SDK Layer — on iOS, HaapiLogger.followUpTags is an emission gate (default empty array → nothing logs; the UI Layer requires UIKitFollowUpTag.allCases). On Android, tags have no behavioural effect on emission — gating is via enabled and setLevel(...) only, and tags travel through to your sink as labels. If you want UI-only output, filter by tag prefix inside your LogSink.log(...) or at the LogCat command line.

HaapiLogger.followUpTags = DriverFollowUpTag.allCases
    + SdkFollowUpTag.allCases
    + UIKitFollowUpTag.allCases
HaapiLogger.setLogType(LogType.info)

class ClientApplication : Application(), HaapiUIWidgetApplication {
    override fun onCreate() {
        super.onCreate()
        HaapiLogger.enabled = true
        HaapiLogger.setLevel(HaapiLogger.LogLevel.INFO)
    }

    override val widgetConfiguration: WidgetConfiguration = /* ... */
}

Sensitive-Value Masking#

HaapiLogger.isSensitiveValueMasked defaults to true and should remain true in any non-development build. The UI Layer composes the SDK Layer, which is where access tokens, refresh tokens, DPoP proofs, and dpop-nonce headers flow — disabling masking surfaces them all in log output. When disabled, the logger emits an explicit warning every time it prints an unmasked sensitive value so the misconfiguration is hard to miss.

Custom Sinks#

Register a LogSink implementation to route every log record (including UI-Layer ones) into your host application’s logger or crash reporter. The sink mechanism is identical across layers — a single registered sink receives Driver, SDK, and UI-Layer records, distinguished by their HAAPI_DRIVER_* / HAAPI_SDK_* / HAAPI_UI_* follow-up tag. The UI Layer adds no new sink surface; it just emits additional tags that flow through the same sink.

See Logging (SDK Layer) for the per-platform LogSink implementation and registration code.