docs(payments): intercept wallet deeplinks on API 23 in Android PayWebView sample

payments/wallets/webview.mdx

@@ -165,7 +165,14 @@ export function PayWebView({gatewayUrl, appDeepLink, onSuccess, onFailure}: PayW
         Linking.openURL(request.url).catch(console.warn);
         return false;
       }
-      return true;
+      // Allow https (the checkout) and about:; block any other scheme so the
+      // page can't drive the OS into arbitrary native schemes (tel:, sms:, …).
+      try {
+        const scheme = new URL(request.url).protocol;
+        return scheme === 'https:' || scheme === 'about:';
+      } catch {
+        return false;
+      }
     },
     [],
   );
@@ -208,6 +215,7 @@ const styles = StyleSheet.create({webview: {flex: 1}});
 
 ```kotlin
 import android.content.ActivityNotFoundException
+import android.content.Context
 import android.content.Intent
 import android.net.Uri
 import android.os.Handler
@@ -232,6 +240,24 @@ fun isWalletDeeplink(url: String): Boolean = try {
     Uri.parse(url).getQueryParameter("uri")?.startsWith("wc:") == true
 } catch (_: Exception) { false }
 
+// Shared by both shouldOverrideUrlLoading overloads. Returns true = handled (don't load
+// in the WebView), false = let the WebView load it. Forward wc: wallet deeplinks to the OS;
+// allow https (the checkout) and about: to load; block any other scheme (tel:, sms:,
+// intent:, …) so the page can't drive the OS into arbitrary native apps.
+private fun handleWalletDeeplink(context: Context, url: String?): Boolean {
+    if (url == null) return false
+    if (isWalletDeeplink(url)) {
+        try {
+            context.startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(url)))
+        } catch (_: ActivityNotFoundException) {
+            // No app can handle the wallet deeplink (wallet not installed).
+        }
+        return true
+    }
+    val scheme = Uri.parse(url).scheme?.lowercase()
+    return scheme != "https" && scheme != "about"
+}
+
 @Composable
 fun PayWebView(
     gatewayUrl: String,
@@ -274,22 +300,16 @@ fun PayWebView(
                     "ReactNativeWebView"
                 )
                 webViewClient = object : WebViewClient() {
-                    // This WebResourceRequest overload is API 24+. If you support minSdk < 24,
-                    // also override the deprecated shouldOverrideUrlLoading(view, url: String) and
-                    // run the same isWalletDeeplink check — otherwise deeplink interception
-                    // silently no-ops on API 23.
-                    override fun shouldOverrideUrlLoading(view: WebView?, request: WebResourceRequest?): Boolean {
-                        val reqUrl = request?.url?.toString() ?: return false
-                        if (isWalletDeeplink(reqUrl)) {
-                            try {
-                                context.startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(reqUrl)))
-                            } catch (_: ActivityNotFoundException) {
-                                // No app can handle the wallet deeplink (wallet not installed).
-                            }
-                            return true
-                        }
-                        return false
-                    }
+                    // API 24+ overload.
+                    override fun shouldOverrideUrlLoading(view: WebView?, request: WebResourceRequest?): Boolean =
+                        handleWalletDeeplink(context, request?.url?.toString())
+
+                    // Deprecated pre-API-24 overload — still the only one called on API 23, so
+                    // without it deeplink interception silently no-ops there and wc: links would
+                    // load inside the WebView instead of opening the wallet.
+                    @Suppress("DEPRECATION")
+                    override fun shouldOverrideUrlLoading(view: WebView?, url: String?): Boolean =
+                        handleWalletDeeplink(context, url)
                 }
                 loadUrl(buildPayUrl(gatewayUrl, appDeepLink))
             }
@@ -458,7 +478,13 @@ class _PayWebViewState extends State<PayWebView> {
             }
             return NavigationDecision.prevent;
           }
-          return NavigationDecision.navigate;
+          // Allow https (the checkout) and about:; block any other scheme so the
+          // page can't drive the OS into arbitrary native schemes (tel:, sms:, …).
+          final scheme = Uri.tryParse(request.url)?.scheme.toLowerCase();
+          if (scheme == 'https' || scheme == 'about') {
+            return NavigationDecision.navigate;
+          }
+          return NavigationDecision.prevent;
         },
       ))
       ..addJavaScriptChannel('ReactNativeWebView', onMessageReceived: (msg) {