xamarin form App refresh on background or minimized - xamarin

I need to refresh the application when push notification came at background. without opening push notification UI is not affecting .
Have anyone know how to update the application when its minimized where new update came. I have read Background fetch with perform fetch in xamarin forms but didn't get sufficient info anyone help please... Thanks.

UI actions must be performed on UI thread. If you want to make change on ui in background then you need to do it in MainThread like below:
Device.BeginInvokeOnMainThread (() => {
labelNotificationCount.Text = "1";
});
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Related

Vaadin how to capture / handle refresh, reload event

I started learning Vaadin recently, up to this point i did not have much experience with web-based applications, so my question might be very basic.
I want to use eventbus, when create a new layout i register it in the eventbus, it looks like this:
this.addDetachListener(e ->{
eventbus.getBus().unregister(this);
System.out.println("addDetachListener");
}
);
this.addAttachListener(e ->{
eventbus.getBus().register(this);
System.out.println("addAttachListener");
}
);
My problem occurs when i refresh the page, I noticed that every time when i reload the page (hit the reload button in the webbrowser) Vaadin is creating new UI and register this view in the eventbuss.
When i click refresh button i expect detachListener to fire up, but it does not work, so i end up with many UI registered in the eventbuss.
How can i capture refresh event in Vaadin ?

How to Close/Exit current instance of Xamarin.Forms app while loading a new one

We are facing a strange issue. Not sure if it is design flaw of the existing application. Your help/suggestion is appreciated.
We have a Xamarin.forms app. Targeted both for iOS and Android.
Problem is coming mainly in Android app.
Application flow:
once we logout from the application, app opens an logout activity and delete user info and other data.
opens a new activity for login which contains client SSO implementation
on successful login, app is setting user info and fetch data from web service.
then it calls LoadApplication method so that flow comes back in main application
Now if user perform logout/login several times, its opening a new application instance by calling LoadApplication method and then displaying home screen
So when user is tapping back button in home page, app is not closing and displays previous instance of same application.
User need to press back button several times (depending how many time user perform logout-login).
Is there any goodway to stop this?
Can we close current instance of the application before LoadApplication being called?
Stuck for a long time.
I'd try to avoid to call LoadApplication more then once. You should control the navigation stack.
Given you are on the LogoutPage
remove all views via PopToRootAsync
show the LoginPage
await Navigation.PopToRootAsync(false);
await Navigation.PushAsync(new LoginPage(), true);
This blog post may be worth a reading: https://jfarrell.net/2015/01/22/understanding-xamarin-forms-navigation/
Kindly try this.
https://stackoverflow.com/a/36885388/1941942
[Activity (NoHistory = true)]
public class LoginActivity : Activity { }
The saving instance error has gone a while after I implement it on MainActivity.

The equivalent to onResume() in Windows Phone 7

I'm looking for some app life cycle help from the wp7 experts. My app has a refresh step in a specific page but I only want to launch this when the user brings the app to life from the background.
Note- The life cycle step I'm looking for isn't called when the page is init() only when I'm navigated (back) to or the user has taken a phone call and then re-opens the app (keeping the same page open)
Thank you in advance
what you are looking for is called Tombstoning and you can find a great article at http://wildermuth.com/2010/10/17/Architecting_WP7_-_Part_5_of_10_Tombstoning
The events are:
Launching (opened from tile)
Deactivated (user takes a call or something)
Activated (back from the call)
Closing (Leaves you app via the "Back" button)
You are looking for the Activated event. These are in your App.xaml.cs/vb file. Hook into the event, and update your data model. When your page is bound to that model it will get the data.
If you are not using MVVM, and can't really refresh from that event, you can do it using the PhoneApplicationService.Current.StartupMode property. It has two options Activate (what you are looking for) and Launch (loaded fresh from the tile). It would look something like
Init()
{
if (PhoneApplicationService.Current.StartupMode == StartupMode.Activate)
{
Refresh()
}
}

How to get to the Messaging app to text someone?

I'm making an app and I want to be able to go from my app to the messaging app straight to the "Create new" page. Is there a way I can navigate to that page straight from my app?
As Andrew M mentioned, the SmsComposeTask is the correct control to use. Here is some sample code for you:
SmsComposeTask smsTask = new SmsComposeTask();
smsTask.To = "0123456789"; // the number you would like to send the sms to
smsTask.Body = "Some prefilled text..."; // if you would like to fill some text
smsTask.Show();
When Show() is called, the app will navigate to the Messaging application and display an SMS filled in with the defined parameters.
Simply use the above code in an event handler (i.e., the event for when a button is clicked), and the user will be navigated accordingly.
Use the SMSComposeTask:
http://www.nickharris.net/2010/09/how-to-sms-using-the-smscomposetask-for-windows-phone-7/

Show a Dialog Box from non event thread

I need to show a Dialog box, from an app started via an alternate entry point, when a push message arrives.
To do this I need to create an Application instance from the alternate entry point and listen for incoming push.
The problem is when I extend my application class from UiApplication, and call enterEventDispatcher() from the alternate entry point it shows an application icon in running applications forever.
I need to listen for push messages and alert user by a dialog without having an application icon.
So is there any way I can show a dialog from an alternate entry point without a UI event thread?
You can use global dialog. Just use this code.
synchronized (Application.getEventLock()) {
UiEngine ui = Ui.getUiEngine();
Screen screen = new Dialog(Dialog.D_OK, "Look out!!!", Dialog.OK,
Bitmap.getPredefinedBitmap(Bitmap.EXCLAMATION),
Manager.VERTICAL_SCROLL);
ui.pushGlobalScreen(screen, 1, UiEngine.GLOBAL_QUEUE);
}

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