如何在android WebView中使用服务工作者？

WebView webView = findViewById(R.id.webView);
WebSettings webSettings = webView.getSettings();
webSettings.setJavaScriptEnabled(true);

webView.setWebViewClient(new WebViewClient() {
    @Override
    public void onPageFinished(WebView view, String url) {
        super.onPageFinished(view, url);
        // 注册服务工作者
        webView.evaluateJavascript("navigator.serviceWorker.register('/sw.js')", null);
    }
});

self.addEventListener('install', function(event) {
    event.waitUntil(
        caches.open('my-cache').then(function(cache) {
            return cache.addAll([
                '/index.html',
                '/styles.css',
                '/script.js'
            ]);
        })
    );
});

self.addEventListener('fetch', function(event) {
    event.respondWith(
        caches.match(event.request).then(function(response) {
            return response || fetch(event.request);
        })
    );
});