Troubleshooting

import React from 'react'
import { Linking } from 'react-native'
import { WebView } from 'react-native-webview'

export default function MyWebView() {
  return (
    <WebView
      source={{ uri: 'https://yourdomain.com' }}
      onShouldStartLoadWithRequest={({ url }) => {
        if (url.startsWith('metamask://') || url.startsWith('trust://')) {
          Linking.openURL(url).catch(console.warn)
          return false
        }
        return true
      }}
    />
  )
}

func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction,
            decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
    if let url = navigationAction.request.url {
        let scheme = url.scheme ?? ""
        if scheme == "metamask" || scheme == "trust" {
            UIApplication.shared.open(url, options: [:], completionHandler: nil)
            decisionHandler(.cancel)
            return
        }
    }
    decisionHandler(.allow)
}

- (void)webView:(WKWebView *)webView
  decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction
  decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {

    NSURL *url = navigationAction.request.URL;
    NSString *scheme = url.scheme;
    if ([scheme isEqualToString:@"metamask"] || [scheme isEqualToString:@"trust"]) {
        [[UIApplication sharedApplication] openURL:url options:@{} completionHandler:nil];
        decisionHandler(WKNavigationActionPolicyCancel);
        return;
    }

    decisionHandler(WKNavigationActionPolicyAllow);
}

webView.webViewClient = object : WebViewClient() {
    override fun shouldOverrideUrlLoading(view: WebView?, request: WebResourceRequest?): Boolean {
        val url = request?.url.toString()
        val scheme = request?.url?.scheme ?: ""

        if (scheme == "metamask" || scheme == "trust") {
            try {
                val intent = Intent(Intent.ACTION_VIEW, Uri.parse(url))
                view?.context?.startActivity(intent)
            } catch (e: Exception) {
                Log.e("WebView", "Cannot open $scheme link", e)
            }
            return true
        }

        return false // let WebView handle the rest
    }
}

webView.setWebViewClient(new WebViewClient() {
    @Override
    public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
        Uri uri = request.getUrl();
        String scheme = uri.getScheme();

        if ("metamask".equals(scheme) || "trust".equals(scheme)) {
            try {
                Intent intent = new Intent(Intent.ACTION_VIEW, uri);
                view.getContext().startActivity(intent);
            } catch (Exception e) {
                Log.e("WebView", "Cannot open scheme: " + scheme, e);
            }
            return true;
        }

        return false;
    }
});

import 'package:flutter/material.dart';
import 'package:webview_flutter/webview_flutter.dart';
import 'package:url_launcher/url_launcher.dart';

class WebViewPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: WebView(
        initialUrl: 'https://yourdomain.com',
        navigationDelegate: (NavigationRequest request) {
          final uri = Uri.parse(request.url);
          if (uri.scheme == 'metamask' || uri.scheme == 'trust') {
            launchUrl(uri);
            return NavigationDecision.prevent;
          }
          return NavigationDecision.navigate;
        },
        javascriptMode: JavascriptMode.unrestricted,
      ),
    );
  }
}