Set Constraint

        [ChildView setFrame:ParentView.bounds];

        [ParentView addSubview: ChildView];

        

        [ChildView.centerXAnchor constraintEqualToAnchor: ParentView.centerXAnchor].active = true;

        [ChildView.centerYAnchor constraintEqualToAnchor: ParentView.centerYAnchor].active = true;