Nativescript-Angular handling back button to change vizibility

Question

I am trying to change visibility of an element in the back button event.

 <ActionItem icon="~/images/menu_3_dots.png"  ios.position="right" android.position="right"   *ngIf="isActionItemVisible"></ActionItem>

 constructor(private router: Router, private page: Page) {        
         application.android.on(application.AndroidApplication.activityBackPressedEvent, (args: any) => {           
                        args.cancel = true;
                        console.log("Is backbutton pressed !");
                        this.isActionItemVisible= false;
        });          
}         

The variable become false but the element doesn't hide.

Answer 1

You sometime need to tell angular to do a detection cycle to apply changes :

constructor(private router: Router, private page: Page, private cdr: Change
DetectionRef) {        
         application.android.on(application.AndroidApplication.activityBackPressedEvent, (args: any) => {           
                        args.cancel = true;
                        console.log("Is backbutton pressed !");
                        this.isActionItemVisible= false;
                        this.cdr.detectChanges();
        });          
}