AppDNAScreenDelegate

```
public interface AppDNAScreenDelegate

                    
```
SPEC-070-A B.6 — Server-driven screen lifecycle delegate.
Mirrors iOS AppDNAScreenDelegate (AppDNA+Delegates.swift:78-83). The fourth method (onScreenAction) returns Boolean for veto/intercept — false prevents default handling so hosts can fully replace the action behavior.
All methods have default implementations so hosts can implement only the callbacks they care about.
Hosts register via ScreenManager.shared.setDelegate.

Method Summary

Modifier and Type	Method	Description
`Unit`	`onScreenPresented(String screenId)`	Called immediately after a screen has been presented.
`Unit`	`onScreenDismissed(String screenId, Map<String, Object> result)`	Called when a screen is dismissed.
`Unit`	`onFlowCompleted(String flowId, Map<String, Object> result)`	Called when a flow finishes (completed OR abandoned).
`Boolean`	`onScreenAction(String screenId, Map<String, Object> action)`	SPEC-070-A B.6 — veto hook.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - onScreenPresented
```
 Unit onScreenPresented(String screenId)
```
    Called immediately after a screen has been presented.
  - onScreenDismissed
```
 Unit onScreenDismissed(String screenId, Map<String, Object> result)
```
    Called when a screen is dismissed. result mirrors iOS ScreenResult shape: keys include screen_id, dismissed, responses, last_action, duration_ms, optional error.
  - onFlowCompleted
```
 Unit onFlowCompleted(String flowId, Map<String, Object> result)
```
    Called when a flow finishes (completed OR abandoned). result mirrors iOS FlowResult: keys include flow_id, completed, last_screen_id, responses, screens_viewed, duration_ms, optional error.
  - onScreenAction
```
 Boolean onScreenAction(String screenId, Map<String, Object> action)
```
    SPEC-070-A B.6 — veto hook. Return false to intercept the action and prevent the SDK's default handling (e.g. so the host can perform its own navigation, render its own paywall, etc). Return true (default) to let the SDK process the action normally.
    action keys mirror iOS SectionAction payload: type (e.g. "navigate", "deep_link", "show_paywall", "track", "custom"), plus type-specific fields (target_screen_id, url, paywall_id, event_name, event_properties, value, etc).