Pdf Viewer Apis

Functions to open PDF files in a native, in-app viewer instead of downloading them or handing them off to an external app.

The WebToNative PDF Viewer plugin renders the file natively — search, thumbnails, password-protected files, download, and share are all handled in-app.

You'll need to import the javascript file in your website before starting from this link.

Platform support: Android and iOS.

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Setting Up PDF Viewer

1. Go to your WebToNative dashboard → Add-ons → PDF Viewer and enable it.

2. Configure the toolbar/behavior options you want under the same add-on page:

Dashboard field	Maps to	Default	Description
Toolbar Title	toolbarTitle	(uses the title passed from JS)	Overrides the title argument if set to a non-blank value.
Show Download	showDownload	Off	Shows a download-to-device button in the toolbar.
Show Share	showShare	Off	Shows a share-sheet button in the toolbar.
Show Search	showSearch	Off	Shows an in-document search button.
Show Thumbnails	showThumbnails	Off	Shows a page-thumbnail grid button.
Show Page Indicator	showPageIndicator	Off on Android, On on iOS ⚠	Shows a page-number pill at the bottom. See the platform-difference hint below.
Auto-Detect PDF Links	autoDetectLinks	Off	If a link the user taps inside your site resolves to a .pdf URL, opens it in the native viewer instead of navigating the WebView. See Auto-Detect Matching below.
URL Patterns	urlPatterns	(empty)	Only used when Auto-Detect is on — see below.
Error Message	errorMessage	(native default message)	Custom text shown if a PDF fails to load.
Error Button Text	errorButtonName	"Retry"	Label for the retry button on the error screen.

showPageIndicator defaults differently per platform when left unset. Android hides the page indicator by default; iOS shows it by default. If you need identical behavior on both platforms, set this explicitly in the dashboard rather than relying on the default.

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JavaScript API Reference

openPDF

Opens a PDF from a URL in the native in-app viewer.

Plain Javascript

window.WTN.openPDF({
  url: "https://example.com/files/manual.pdf",
  title: "Product Manual",
});

npm

import { openPDF } from "webtonative";

openPDF({
  url: "https://example.com/files/manual.pdf",
  title: "Product Manual",
});

Parameters:

Key	Type	Required	Description
url	String	Yes	The URL of the PDF to open. Throws a JavaScript error immediately (before reaching native code) if blank.
title	String	No	Shown in the viewer's toolbar, unless the dashboard's Toolbar Title field is set to a non-blank value, which takes priority.

openPDF has no callback parameter. All viewer configuration (search, thumbnails, password handling, download, share, auto-detect) comes from the dashboard settings above, not from additional arguments to this call — there is nothing else to pass here beyond url and title.

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Auto-Detect Matching Differs By Platform

If you enable Auto-Detect PDF Links, the matching rule against urlPatterns is not identical on both platforms:

• Android opens the viewer for any URL simply ending in .pdf. urlPatterns is only consulted as a fallback for URLs that don't end in .pdf (substring match).

• iOS requires the URL to both end in .pdf and match at least one entry in urlPatterns as a prefix. A bare .pdf URL with Auto-Detect on and no urlPatterns configured will open automatically on Android but not on iOS.

If you need consistent behavior, always fill in urlPatterns explicitly rather than relying on the "any .pdf URL" fallback that only exists on Android.

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Frequently Asked Questions

Why does the page-number indicator show on iOS but not Android with the same config?

showPageIndicator defaults to off on Android and on iOS when left unset in the dashboard. Set it explicitly if you need matching behavior across platforms.

Can I pass search/thumbnails/download settings directly in the `openPDF()` call?

No — openPDF only accepts url and title. Everything else is configured once, for the whole app, via the dashboard's PDF Viewer add-on settings.

What happens if a PDF requires a password?

The viewer shows a native password-entry screen and retries opening the file once a password is submitted. There is currently no JavaScript event for "password required" — the user is prompted entirely natively.