Execute callback function into ionic fcm onNotification

Ionic Framework ionic-v3
1

Hello friends, when trying to call a function that is in the same ts file, within onNotification, it does not update the data until some action happens, example opened the menu

I attach images of examples

I need that when receiving a notification in foreground the data of a label is changed, in this case I only do it with an input or a checkbox to show the example

code constructor

this.fcm.onNotification().subscribe(data => {
            if(data.wasTapped){
                console.log("Received in background");
            } else {
                 console.log("Received in foreground");
                 this.callback();
            };
        });

I attach example images of the process

app example
PNG

send notification from fcm

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12.PNG1000×211 7.19 KB

Notification is received but no changes occur when you open the menu for example, change the interface
PNG

and when you close the menu the interface changes

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Any suggestions? thanks!!