Xamarin.Forms universal linking to Android always re-creates the app.

Question

I am working on having my App support universal Linking.
I have it working on UWP and am moving on to Android.

The linking seems to work fine and I can start my app running on Android using a link using the command
adb shell am start -a android.intent.action.VIEW -c android.intent.category.BROWSABLE -d "http://mydomain.com.com/xxx

My problem is that if the app is already running and the link is used, the the running app is restarted from the begining.
In other words, OnCreate is called again on a new instance of MainActivity and a new MainPage is created on the call to new App()

Interestingly, the OnNewIntent override is never called. Only the OnAppLinkRequestReceived in the shared project App.xaml.cs. and it receives the Url.

This is an issue because a user hitting a link for the app will lose their state.

Any help would be appreciated

Answer 1

Hello,​

Welcome to our Microsoft Q&A platform!

Please add LaunchMode =LaunchMode.SingleTask, in your Activity tag like following screenshot.

Basically what this does is create a new task and a new instance will be pushed to the task as the root one. However, if any activity instance exists in any tasks, the system routes the intent to that activity instance through the onNewIntent() method call. In this mode, activity instances can be pushed to the same task. And if the user clicks the BACK key from the current activity, the system will return the user to the previous activity.

For more details, you can refer to this thread.
https://stackoverflow.com/a/47452460/10627299

Best Regards,

Leon Lu

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Answer 2

Thanks to @Leon Lu (Shanghai Wicresoft Co,.Ltd.)

Should be noted that the default processing for OnNewIntent is to call SendOnAppLinkRequestReceived with the intent URI. This, in turn will call OnAppLinkRequestReceived in the Shared Code project.

Many examples I have seen regarding universal link, had code like in MainActivity.cs

 protected override void OnNewIntent(Intent intent) {  
    // perform any uri processing here  
    _app.SendOnAppLinkRequestReceived(new Uri(intent.Data);  
    base.OnNewIntent(intent);  
}  

This is unnecessary since _app.SendOnAppLinkRequestReceived(new Uri(intent.Data); will call your OnAppLinkRequestReceived which is what the base OnNewIntent will do anyway. Calling base.OnNewIntent actually calls OnAppLinkRequestReceived again.

Any code to parse and take action on the uri is better off done in the Shared code which will handle linking from all platforms.