custom 'add' view animation to uistackview - ios

Question

I'm playing with iOS9 uistackview and having problems to customize animation when adding element. You can notice that the yellow element position is being animated from top-left corner and starting with zero width.
I would like yellow element already being positioned below violet element and animate only height from 0 to some value (inverse behavior of green element animation)
I know its easy to do it when element is already in arrangeViews hierarchy unfortunately in my project I have to add and remove items dynamically at arbitrary index. Code below:
#interface ViewController ()
{
NSLayoutConstraint* heightConstraint2;
UIStackView *stackView;
}
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
//View 1
UIView *view1 = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 60)];
view1.backgroundColor = [UIColor blueColor];
[view1.heightAnchor constraintEqualToConstant:60].active = true;
[view1.widthAnchor constraintEqualToConstant:300].active = true;
//View 2
UIView *view2 = [[UIView alloc] init];
view2.backgroundColor = [UIColor greenColor];
// [view2.heightAnchor constraintEqualToConstant:100].active = true;
[view2.widthAnchor constraintEqualToConstant:70].active = true;
heightConstraint2 = [view2.heightAnchor constraintEqualToConstant:100];
heightConstraint2.active = true;
//View 3
UIView *view3 = [[UIView alloc] init];
view3.backgroundColor = [UIColor magentaColor];
[view3.heightAnchor constraintEqualToConstant:100].active = true;
[view3.widthAnchor constraintEqualToConstant:180].active = true;
//Stack View
stackView = [[UIStackView alloc] init];
stackView.axis = UILayoutConstraintAxisVertical;
stackView.distribution = UIStackViewDistributionEqualSpacing;
stackView.alignment = UIStackViewAlignmentCenter;
stackView.spacing = 0;
[stackView addArrangedSubview:view1];
[stackView addArrangedSubview:view2];
[stackView addArrangedSubview:view3];
stackView.translatesAutoresizingMaskIntoConstraints = false;
[self.view addSubview:stackView];
}
-(void)viewDidAppear:(BOOL)animated {
heightConstraint2.constant = 0;
UIView *view4 = [[UIView alloc] init];
view4.backgroundColor = [UIColor yellowColor];
[view4.heightAnchor constraintEqualToConstant:80].active = true;
[view4.widthAnchor constraintEqualToConstant:180].active = true;
NSLayoutConstraint* heightConstraint4 = [view4.heightAnchor constraintEqualToConstant:0];
[stackView insertArrangedSubview:view4 atIndex:3];
// [stackView layoutIfNeeded];
heightConstraint2.constant = 0;
heightConstraint4.constant = 80;
[UIView animateWithDuration:0.5
delay:3
options: UIViewAnimationOptionCurveEaseInOut
animations:^{
[stackView layoutIfNeeded];
}
completion:nil];
}

Answer 1

Add your view but set it as hidden, Then in animationBlock, set hidden = true