Xamarin Forms multiple instances of same app open

Research:

Are you having an issue where multiple instances of a Xamarin Forms app can launch and sometimes on top of each other? The issue is usually caused when the application is already running and the app gets launched again from the home screen rather than the recent applications menu.

After some Googling, you might find answers such as these:

https://stackoverflow.com/questions/4341600/how-to-prevent-multiple-instances-of-an-activity-when-it-is-launched-with-differ

You might also come across answers where people tell you to set the launch mode in the application manifest mode. These people would be pretty close to the actual answer, but in actual reality, the application manifest for Android within Xamarin Forms doesn't seem to affect the behavious of the app in regards to it's launch mode.

That's when I started looking into the actual documentation for launch mode on Xamarin Forms, and after reading up on the subject here:

https://developer.xamarin.com/api/type/Android.App.ActivityAttribute/ 

The fix:

It turns out that this indeed the fix, but it's not the applications manifest that you need to modify, it's the MainActivity class. See my example below Where I set 'LaunchMode = LaunchMode.SingleInstance'.

[Activity(Label = "My App Name", Icon = "@drawable/icon", Theme = "@style/MainTheme", MainLauncher = false, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation, LaunchMode = LaunchMode.SingleInstance)]
public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
{
    ....
}


Published at

Tags: Xamarin,Xamarin Forms,Android,C#

Luke Alderton

Comments

Shane
Thanks! Exactly what I was looking for.
14/12/2018
cxfranco
Excellent, Good article. Thanks
18/01/2019
Post a comment
Sit tight...
We're adding your comment.
Thank you.
Your comment has been added.
There's been a problem.
Please try again later.
Share with
Tags
Latest Comments
By esrgr on JQuery Unobtrusive Validation for dynamically created elements
11 Jun 2019, 06:01 AM
By annualmars on Raspberry Pi - Running Java app on Raspbian
10 May 2019, 15:48 PM
By Shahriar H. Razi on Xamarin Forms - Working with threads
7 May 2019, 09:25 AM
By Person on MVC forms in Umbraco
30 Apr 2019, 13:33 PM
By christopher on How to add a Xamarin Forms Loading Screen/Overlay
27 Mar 2019, 11:59 AM
By Rezi on Xamarin forms - Stop/Cancel back button event
22 Mar 2019, 13:08 PM
By jack of ass on Replacing the Xamarin Header/Navigation bar with a custom view/template
16 Feb 2019, 03:13 AM
By Zal on Xamarin MasterDetailPage has large margin/padding at top
7 Feb 2019, 12:20 PM
Categories
App Development
Event
Game Development
Mapping
Modelling
Programming
Review
Robotics
Tutorial
Web Development