Screen Lifecycle Instrumentation

Generates: Spans

Automatically tracks UIViewController transitions and emits spans for each screen's creation, appearance, and active session.

How It Works

The SDK swizzles UIViewController.viewDidLoad, viewWillAppear, and viewDidDisappear at the class level. Every UIViewController subclass is tracked automatically — no per-screen code is needed.

Configuration

Screen lifecycle tracking is enabled by default.

Pulse.shared.initialize(
    endpointBaseUrl: "https://your-backend.com",
    apiKey: "your-api-key",
    instrumentations: { config in
        config.screenLifecycle { $0.enabled(true) }  // default: true
    }
)

What Gets Tracked

Event	Span Name	Triggered By
First load	Created	viewDidLoad
Reappearing from background/navigation	Restarted	viewWillAppear (after disappear)
Leaving the screen	Stopped	viewDidDisappear
Time screen was active (appear → disappear)	ViewControllerSession	Closed on viewDidDisappear

Generated Telemetry

Type: Span
Span Kind: Internal
pulse.type: screen_load (Created/Restarted spans) · screen_session (ViewControllerSession span)

Attributes

Attribute	Description	Example	Always Present
pulse.type	"screen_load" for load spans, "screen_session" for session span	"screen_session"	✅ Yes
screen.name	UIViewController class name	"CheckoutViewController"	✅ Yes
session.id	Current session identifier	"f40364c92b85ec0c19c35a65be42b97f"	✅ Yes

Sample Payload

{
  "name": "ViewControllerSession",
  "kind": "INTERNAL",
  "attributes": {
    "pulse.type": "screen_session",
    "screen.name": "ProductDetailViewController",
    "session.id": "f40364c92b85ec0c19c35a65be42b97f"
  }
}

SwiftUI

Screen lifecycle instrumentation tracks UIViewController — it does not automatically track SwiftUI View navigation. Apps that use UIHostingController wrapping SwiftUI views will see the hosting controller tracked (with its class name). Pure SwiftUI navigation (e.g., NavigationStack pushes) does not create screen lifecycle spans.

Disabling Screen Lifecycle Instrumentation

config.screenLifecycle { $0.enabled(false) }