Skip to content
This repository has been archived by the owner on Jun 13, 2024. It is now read-only.

Commit

Permalink
[web] Migrate index.html to use flutter.js (#630)
Browse files Browse the repository at this point in the history
* Use flutter.js to load the app.

* Call runApp ASAP.

Also:
* Align body styles with flutter's while loading, so the logo doesn't
  jump around too much.
* Document why this needs to wait a few hundred ms before removoing the
  loading indicator (so users can _see_ the zoom animation at all!)
  • Loading branch information
ditman authored Apr 8, 2022
1 parent 637e6a3 commit 8803fd5
Showing 1 changed file with 57 additions and 63 deletions.
120 changes: 57 additions & 63 deletions web/index.html
Original file line number Diff line number Diff line change
Expand Up @@ -33,74 +33,68 @@
}
</style>
<link rel="manifest" href="manifest.json">
</head>
<body>
<!-- This script installs service_worker.js to provide PWA functionality to
application. For more information, see:
https://developers.google.com/web/fundamentals/primers/service-workers -->
<script>
// The value below is injected by flutter build, do not touch.
var serviceWorkerVersion = null;
var scriptLoaded = false;
function loadMainDartJs() {
if (scriptLoaded) {
return;
}
scriptLoaded = true;
var scriptTag = document.createElement('script');
scriptTag.src = 'main.dart.js';
scriptTag.type = 'application/javascript';
document.body.append(scriptTag);
}
</script>
<script src="flutter.js" defer></script>
</head>
<body>

if ('serviceWorker' in navigator) {
// Service workers are supported. Use them.
window.addEventListener('load', function () {
// Wait for registration to finish before dropping the <script> tag.
// Otherwise, the browser will load the script multiple times,
// potentially different versions.
var serviceWorkerUrl = 'flutter_service_worker.js?v=' + serviceWorkerVersion;
navigator.serviceWorker.register(serviceWorkerUrl)
.then((reg) => {
function waitForActivation(serviceWorker) {
serviceWorker.addEventListener('statechange', () => {
if (serviceWorker.state == 'activated') {
console.log('Installed new service worker.');
loadMainDartJs();
}
});
}
if (!reg.active && (reg.installing || reg.waiting)) {
// No active web worker and we have installed or are installing
// one for the first time. Simply wait for it to activate.
waitForActivation(reg.installing || reg.waiting);
} else if (!reg.active.scriptURL.endsWith(serviceWorkerVersion)) {
// When the app updates the serviceWorkerVersion changes, so we
// need to ask the service worker to update.
console.log('New service worker available.');
reg.update();
waitForActivation(reg.installing);
} else {
// Existing service worker is still good.
console.log('Loading app from service worker.');
loadMainDartJs();
}
});
<div id="loading">
<style>
body {
inset: 0; overflow: hidden;
margin: 0; padding: 0;
position: fixed;
}
#loading {
align-items: center;
display: flex;
height: 100%;
justify-content: center;
width: 100%;
}
#loading img {
animation: 1s ease-in-out 0s infinite alternate breathe;
opacity: .66;
transition: opacity .4s;
}
#loading.main_done img {
opacity: 1;
}
#loading.init_done img {
animation: .33s ease-in-out 0s 1 forwards zooooom;
opacity: .05;
}
@keyframes breathe { from { transform: scale(1) } to { transform: scale(0.95)}}
@keyframes zooooom { from { transform: scale(1) } to { transform: scale(10)}}
</style>
<img src="icons/Icon-192.png" alt="Loading indicator..." />
</div>

// If service worker doesn't succeed in a reasonable amount of time,
// fallback to plaint <script> tag.
setTimeout(() => {
if (!scriptLoaded) {
console.warn(
'Failed to load app from service worker. Falling back to plain <script> tag.',
);
loadMainDartJs();
}
}, 4000);
<script>
window.addEventListener('load', function() {
var loading = document.querySelector('#loading');
_flutter.loader.loadEntrypoint({
serviceWorker: {
serviceWorkerVersion: serviceWorkerVersion,
}
}).then(function(engineInitializer) {
loading.classList.add('main_done');
return engineInitializer.initializeEngine();
}).then(function(appRunner) {
loading.classList.add('init_done');
return appRunner.runApp();
}).then(function(app) {
// Wait a few milliseconds so users can see the "zoooom" animation
// before getting rid of the "loading" div.
window.setTimeout(function() {
loading.remove();
}, 200);
});
} else {
// Service workers not supported. Just drop the <script> tag.
loadMainDartJs();
}
});
</script>

</body>
</html>

0 comments on commit 8803fd5

Please sign in to comment.