Read/Write Value API
Persist small strings on the device from JavaScript and read them back — for theme, language, session tokens, or onboarding state.
The Read/Write Value API persistently stores an arbitrary string on the device (via the app's private storage) and reads it back into your JavaScript. Values survive app restarts and cache clears — unless the OS wipes app data.
Writing a Value:
Everything after writevalue:// is stored verbatim as one string. Design your own format (query-string, JSON, CSV — whatever fits your web app):
<a href="writevalue://darkmode=on;user=42">Save</a>
Reading a Value:
When readvalue:// is triggered, the app injects the stored string back into the WebView so your JavaScript can read it:
<a href="readvalue://" onclick="setTimeout(showSettings, 200)">Load</a>
<script>
function showSettings() {
console.log(window.appSettings || "no settings yet");
}
</script>
Typical Use Cases:
- Remember a user's theme, language, or onboarding state offline.
- Cache a session token when you cannot rely on cookies.
- Persist a small local preference without a backend round-trip.
Notes: Values are per-app-install and per-device — they are not synced across devices. Keep values small; this API is intended for settings, not blob storage.
SDK-style implementation notes
Treat this feature as a native capability exposed to your web layer: keep your production website or PWA as the source of truth, then use the documented WebViewGold configuration flags, URL commands, and JavaScript bridge calls to opt in to native Android behavior only where it adds value. This approach keeps your codebase maintainable because the same web application can serve browsers, WebViewGold for Android, and the other WebViewGold platforms with minimal conditional logic.
For reliable results, prefer HTTPS endpoints, stable route names, explicit success/error states in your UI, and small JavaScript helper functions that wrap native calls. For example, a web app built with jQuery Mobile, Lovable, Base44, Bolt, WordPress, Bubble, a custom React/Vue/Angular stack, or static HTML can expose a single button or event handler that triggers the native WebViewGold API while still showing a graceful browser fallback.
- Recommended integration pattern: detect the app context, call the WebViewGold API, then update your web UI after the native callback or route change.
- Testing checklist: validate the feature on a real device or packaged build, verify permissions and store review text, and confirm that browser-only users still receive a useful fallback.
- SEO benefit: keep feature pages, route titles, and structured content indexable on your website while WebViewGold delivers the native app shell for Android users.