Good evening, in my dapp browser app, when the user requests a chain id change, i use to reload the page, but i found out that it is possible to change chain id without reloading the browser, basically emitting an event the user can pick up as
ethereum.on('chainChanged', (chainId) => {});
the question is how can i emit this event in my flutter dapp browser?.
how i execute javascript from webview
await _controller.evaluateJavascript(
source:'Wallet.executeCallback($id, "$error",null);');
Related
I have developed a Flutter Web app that uses Firebase Authentication in order to sign in users to the app.
I've declared the Firebase Authentication persistence field so that the app will remember and auto-login the user when he revisits the Flutter Web app's URL, and won't be required to re-login every time he launches the URL.
It all works fine on a regular browser, but when the user generates a PWA (for example, clicking "Add to Home Screen" on iOS devices to save the website as PWA), the persistence feature stops working, and the user is required to re-login every time he opens the PWA.
Is there a way to add Firebase Authentication's persistence feature to a PWA? And if not, is there a way to prevent generating a PWA (and saving the Flutter Web app as a regular browser URL when clicking "Add to Home Screen" button on iOS, for example)?
Thank you!
To solve the persistence problem, add a listener:
FirebaseAuth.instance.idTokenChanges().listen((User? user) async {
if (user == null) {
// Function for user not logged in here. Do not write function to change page here.
} else {
// As it's a Future it will take a while to process the user's information, so it
will call the function after it's done.
Navigator.pushReplacement(
context, MaterialPageRoute(builder: (_) => Home()));
}
}
This is an example I made and it worked, use controllers to change the status, put some function to wait for the information to be processed.
Hope this helps. Any questions, at your disposal.
I have a requirement ,in app I need to navigate the user to webview (website) and there will be a form with 5 fields and once the form is submitted a flag to be passed to app and app should work based on the flag .. So how it can be achieved
I have checked that there is a url_launcher or webview_flutter but i don know how to redirect the app once the form is submitted in website
I am not entirely sure if I understood the problem. But here is what can be done.
Open url in webview.
Now you should listen to webview state change. There must be a listener for this. say the listener is webViewStateChanged which will give you the state of webview.
Then you can check like
void webViewStateChanged(WebViewStateChanged newState) async {
if (newState.type != WebViewState.finishLoad ||
newState.url != desiredURL) {
return;
}
// At this point, you want to return to your app. If you need data from
// website, you can do so by accessing cookies of webview.
// Now you are back to the app, you can pop/replace the webview whatever
// is your requirement.
I am trying to keep track of whether a web app has been installed to the user's home-screen using a value in localStorage.
I know there is DOM event that fires when a web app has been installed into a user's home-screen, but is there an event for when it has been uninstalled?
The type of event I have in mind would ideally be scheduled in a manner similar to (and behave in a manner similar to) onunload. (ie. an uncancellable event that allows me to schedule some last bit of work before the app is destroyed)
eg:
window.addEventListener('appinstalled', function(e) {
console.log('onappinstalled', e)
localStorage.setItem('APP_INSTALLED', '1')
})
// given the above, is anything like the following possible?
window.addEventListener('appuninstalled', function(e) {
console.log('onappuninstalled', e)
localStorage.setItem('APP_INSTALLED', '0')
})
I realised that once a user has uninstalled the app from their home-screen, the browser will begin prompting to install the app to the home-screen, again, provided you have met the criteria.
So by using the onbeforeinstallprompt event, there is an opportunity to clear the 'APP_INSTALLED' key from localStorage, and perform other arbitrary work.
eg:
window.addEventListener('beforeinstallprompt', function(e) {
localStorage.removeItem('APP_INSTALLED')
})
Moreover, this localStorage key may have already been cleared if the user elected to delete all data associated with the app when uninstalling the app from their home-screen.
I have been trying for several months to implement an app that receives notifications whose content I want to be stored in the database of my application. I am using the Firebase Messagging plugin and I am receiving the notifications correctly, both in Foreground and in Background.
However, in the background I am unable to execute my callback without the need to press the notification explicitly by the user. Likewise, there is no way to increase the badge of the application when it is not open.
Now, I do not understand how applications like WhatsApp, Telegram and any other application that is not made by mere mortals work. How is it possible that they can get the data in backgroud, manage the badges, synchronize messages, etc? Being that, supposedly the services like Firebase are limited in background. Even with plugins like Background Mode my application is suspended by Android when the user closes it.
The code that I am currently using to handle notifications is the following:
// In foreground (WORKS)
this.firebaseMessaging.onMessage().subscribe((notificacion) => {
// Insert in DB
...
});
// In background (DOESN'T WORK)
this.firebaseMessaging.onBackgroundMessage().subscribe((notificacion) => {
// Insert in DB
...
});
What alternative is left? The only thing that occurs to me is to use notifications in Foreground and background only as a warning. So every time I open the application I'll have to call a message synchronization callback with the server (with badge management included).
If someone has some better way, I would greatly appreciate it if you throw a little light on the subject.
From already thank you very much
Ok, after more than a year I think it's time to close this question. I solved the problem this way:
Suppose I need to get a list of messages. This action is made by a function called getMessages()
When a new message is created in the backend, I send a push notification through Firebase service.
If the push notification is received in foreground I refresh call the method directly:
this.firebaseMessaging.onMessage().subscribe((notificacion) => {
getMessages();
});
If the push notification is received in background and the user taps on it there isn't a problem as it's supported by the plugin:
this.firebaseMessaging.onBackgroundMessage().subscribe((notificacion) => {
getMessages();
});
If the push notification is received in background but the user DOES NOT tap on it and opens the app in another way than the notification, we need to excecute the corresponing function when the app is opened in app.component.ts file:
this.platform.ready().then(() => {
getMessages();
// Extra stuff like this.statusBar.styleDefault(); or this.splashScreen.hide();
});
That way all the cases are considered! You should keep in mind that apps like Whatsapp or Telegram are developed in official technologies like Java or Kotlin which not only have official native plugins, also its code are excecuted natively and not in a limited browser as Cordova or Capacitor frameworks do
I have created a story reading chrome app.
My problem is that whenever the app is relaunched it starts from the first page of the story.
How can i save the last state of the app so that it reloads from the point where it was left?
You can save state of the app using the chrome.storage API.
Suppose you want to store the index of the page, and you have some function to go to a page:
function goToIndex(index){
chrome.storage.local.set({lastIndex: index}, function() {
/* actual work */
});
}
And when your app initializes, read the value (note, it's all asynchronous):
// Safe default if the storage is empty; should be the first page
var defaultIndex = 0;
chrome.storage.local.get({lastIndex : defaultIndex}, function(result) {
goToIndex(result.lastIndex);
});
Optionally, this will also sync progress across browsers for logged in users, which is a nice feature. You can do it by using chrome.storage.sync instead of chrome.storage.local, but beware of rather harsh rate limits. It is best to implement your own rate limiting if you use this.