WebView & UPI setup

val webView = WebView(context)

webView.settings.apply {
  javaScriptEnabled = true          // required
  domStorageEnabled = true          // required — session lives in localStorage
  setSupportMultipleWindows(true)   // required — mandate popup (target SDK 24+)
  javaScriptCanOpenWindowsAutomatically = true
}

// 1. Mandate popup: hand the child window back to the WebView.
webView.webChromeClient = object : WebChromeClient() {
  override fun onCreateWindow(
    view: WebView?, isDialog: Boolean, isUserGesture: Boolean, resultMsg: Message?
  ): Boolean {
    val popup = WebView(context).apply {
      settings.javaScriptEnabled = true
      settings.domStorageEnabled = true
      webViewClient = WebViewClient()
    }
    (resultMsg?.obj as? WebView.WebViewTransport)?.webView = popup
    resultMsg?.sendToTarget()
    return true
  }

  // 2. KYC document / selfie upload.
  override fun onShowFileChooser(
    view: WebView?,
    filePathCallback: ValueCallback<Array<Uri>>?,
    params: FileChooserParams?
  ): Boolean {
    pendingFileCallback = filePathCallback
    startActivityForResult(params!!.createIntent(), REQ_FILE_CHOOSER)
    return true
  }
}

// 3. Forward UPI / intent deep links to the OS.
webView.webViewClient = object : WebViewClient() {
  override fun shouldOverrideUrlLoading(v: WebView?, r: WebResourceRequest?): Boolean {
    val url = r?.url?.toString() ?: return false
    if (url.startsWith("http://") || url.startsWith("https://")) return false
    return try {
      val intent = Intent.parseUri(url, Intent.URI_INTENT_SCHEME)
      context.startActivity(intent)
      true
    } catch (e: Exception) {
      // No UPI app installed — let the SPA fall back to its QR flow.
      true
    }
  }
}

webView.loadUrl(embedUrl)

// Create ONE pool and reuse it — this is what keeps the session alive.
let sharedProcessPool = WKProcessPool()

let config = WKWebViewConfiguration()
config.processPool = sharedProcessPool
config.allowsInlineMediaPlayback = true
config.mediaTypesRequiringUserActionForPlayback = []

let webView = WKWebView(frame: .zero, configuration: config)
webView.uiDelegate = self
webView.navigationDelegate = self
webView.load(URLRequest(url: URL(string: embedUrl)!))

// 1. Forward non-http(s) schemes (upi://, phonepe://, …) to the OS.
func webView(_ webView: WKWebView,
             decidePolicyFor navigationAction: WKNavigationAction,
             decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
  if let url = navigationAction.request.url,
     let scheme = url.scheme?.lowercased(),
     !["http", "https", "about", "file"].contains(scheme) {
    UIApplication.shared.open(url, options: [:], completionHandler: nil)
    decisionHandler(.cancel)
    return
  }
  decisionHandler(.allow)
}

// 2. Mandate popup: load target-blank navigations in the same WebView.
func webView(_ webView: WKWebView,
             createWebViewWith configuration: WKWebViewConfiguration,
             for navigationAction: WKNavigationAction,
             windowFeatures: WKWindowFeatures) -> WKWebView? {
  if navigationAction.targetFrame == nil {
    webView.load(navigationAction.request)
  }
  return nil
}

<key>LSApplicationQueriesSchemes</key>
<array>
  <string>upi</string>
  <string>tez</string>
  <string>gpay</string>
  <string>paytmmp</string>
  <string>phonepe</string>
  <string>bhim</string>
  <string>credpay</string>
  <string>amazonpay</string>
  <string>mobikwik</string>
</array>