Event each time component becomes visible

What I finally did (which is not very beautiful but works while I don’t have a better way to do it…) is to use the ngAfterContentChecked() callback and handle the change myself.

@ViewChild('map') m;
private isVisible: boolean = false;
ngAfterContentChecked(): void
{
    if (this.isVisible == false && this.m.nativeElement.offsetParent != null)
    {
        console.log('isVisible switched from false to true');
        this.isVisible = true;
        this.Refresh();
    }
    else if (this.isVisible == true && this.m.nativeElement.offsetParent == null)
    {
        console.log('isVisible switched from true to false');
        this.isVisible = false;
    }
}