Open the current PDF in an installed PDF viewer app

Call openInExternalApp or requestOpenInExternalApp to hand the current PDF to another app, then observe KPdfExternalOpenState for success or failure.

KPDF can hand the current PDF off to any installed app that handles PDF content — for example, Adobe Acrobat or the system Files app. Call openInExternalApp() to start the flow. The SDK exports the file and triggers the platform’s app-chooser or sends it directly to the default PDF handler. Observe externalOpenState if you want to react to success or failure.

Basic usage

Button(onClick = { viewerState.openInExternalApp() }) {
    Text("Open in external app")
}

openInExternalApp() is an alias for requestOpenInExternalApp(). Both accept the same parameters — use whichever reads more clearly at your call site.

Suggesting a file name

Pass a suggestedFileName to control the name the receiving app sees:

Button(onClick = {
    viewerState.requestOpenInExternalApp(
        suggestedFileName = "report-q1.pdf",
    )
}) {
    Text("Open report in external app")
}

Observing state

Collect externalOpenState to keep your UI in sync with the flow:

val externalOpenState by viewerState.externalOpenState.collectAsState()

Full pattern with state observation

@Composable
fun ExternalAppExample(viewerState: KPdfViewerState) {
    val externalOpenState by viewerState.externalOpenState.collectAsState()

    Button(onClick = {
        viewerState.requestOpenInExternalApp(suggestedFileName = "document.pdf")
    }) {
        Text("Open in external app")
    }

    when (val state = externalOpenState) {
        KPdfExternalOpenState.Idle -> Unit
        KPdfExternalOpenState.Exporting -> {
            Text("Preparing PDF…")
        }
        is KPdfExternalOpenState.AwaitingExternalApp -> {
            Text("Launching external app…")
        }
        is KPdfExternalOpenState.Success -> {
            Text("Opened successfully.")
        }
        is KPdfExternalOpenState.Cancelled -> {
            Text("Cancelled.")
        }
        is KPdfExternalOpenState.Error -> {
            Text("Could not open external app: ${state.reason}")
        }
    }
}

KPdfExternalOpenState variants

State	When it occurs	What it carries	Suggested UI reaction
Idle	No open in progress	—	No indicator
Exporting	SDK is serialising the PDF bytes	—	Show a progress indicator
AwaitingExternalApp	Platform app chooser is open	requestId, suggestedFileName, mimeType	Tell the user to pick an app
Success	External app received the file	requestId, suggestedFileName, mimeType, location?	Dismiss the indicator
Cancelled	User dismissed the app chooser	requestId, suggestedFileName, mimeType	Restore previous UI silently
Error	Export or handoff failed	reason, suggestedFileName?, mimeType?	Show an error message

If no PDF viewer is installed on the device, the platform will report an error. Handle KPdfExternalOpenState.Error and show a message that guides the user to install a PDF app.