如何在不破坏约束的情况下以编程方式将UITextField添加到UIScrollView？

的情况是这样的：我有一个UIScrollView形式嵌入，形式有用户可以在其中添加文本框的N个部分，所以如果一开始我有这样的：如何在不破坏约束的情况下以编程方式将UITextField添加到UIScrollView？

UITextField - textField1 
UIButton - Add

当Add按我想有这样的：

UITextField - textField1 
UITextField - textField2 
UIButton - Add

虽然文本字段添加，约束条件不能满足，因此UI打破

behavior

的日志中：

[LayoutConstraints] Unable to simultaneously satisfy constraints. 
    Probably at least one of the constraints in the following list is one you don't want. 
    Try this: 
     (1) look at each constraint and try to figure out which you don't expect; 
     (2) find the code that added the unwanted constraint or constraints and fix it. 
(
    "<_UILayoutSupportConstraint:0x1c4c800a0 _UILayoutGuide:0x106ccf4e0.height == 64 (active)>", 
    "<_UILayoutSupportConstraint:0x1c4c80050 V:|-(0)-[_UILayoutGuide:0x106ccf4e0] (active, names: '|':UIView:0x106ccdc10)>", 
    "<_UILayoutSupportConstraint:0x1c4c80ff0 _UILayoutGuide:0x106ccf6d0.height == 0 (active)>", 
    "<_UILayoutSupportConstraint:0x1c4c801e0 _UILayoutGuide:0x106ccf6d0.bottom == UIView:0x106ccdc10.bottom (active)>", 
    "<NSLayoutConstraint:0x1c4c80550 UIImageView:0x106cce6c0.height == 5 (active)>", 
    "<NSLayoutConstraint:0x1c4c80640 UILabel:0x106ccf070'Completa tu Perfil'.height == 24 (active)>", 
    "<NSLayoutConstraint:0x1c0c886b0 form-view.height == 579 (active, names: form-view:0x10ed307c0)>", 
    "<NSLayoutConstraint:0x1c0c8a1e0 V:|-(0)-[form-view] (active, names: form-view:0x10ed307c0, '|':UIScrollView:0x107a37000)>", 
    "<NSLayoutConstraint:0x1c0c8a320 V:[form-view]-(0)-[profiles-view] (active, names: profiles-view:0x106ccd430, form-view:0x10ed307c0)>", 
    "<NSLayoutConstraint:0x1c4c80af0 V:[_UILayoutGuide:0x106ccf4e0]-(10)-[UILabel:0x106ccf070'Completa tu Perfil'] (active)>", 
    "<NSLayoutConstraint:0x1c4c80cd0 V:[UILabel:0x106ccf070'Completa tu Perfil']-(8)-[UIImageView:0x106cce6c0] (active)>", 
    "<NSLayoutConstraint:0x1c4c80d20 V:[UIImageView:0x106cce6c0]-(0)-[UIScrollView:0x107a37000] (active)>", 
    "<NSLayoutConstraint:0x1c4c80e10 UIImageView:0x106ccddf0.top == profiles-view.top (active, names: profiles-view:0x106ccd430)>", 
    "<NSLayoutConstraint:0x1c4c80f00 V:[UIImageView:0x106ccddf0]-(0)-[_UILayoutGuide:0x106ccf6d0] (active)>", 
    "<NSLayoutConstraint:0x1c0c8bdb0 'UIView-Encapsulated-Layout-Height' UIView:0x106ccdc10.height == 667 (active)>" 
) 

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x1c0c886b0 form-view.height == 579 (active, names: form-view:0x10ed307c0)>

因此，由于高度的限制被打破，自动版式安排下保证金的限制，允许观点打破了这样的元素。

话虽这么说，我加入限制的方式是这样的：

func addModelButtonAction(_ sender: Any) { // an IBAction 
    addButton.isHighlighted = false 
    let last = modelTextFields.last! 
    let textField = last.createCopy() // extension method for creating a copy of the last textField 
    modelTextFieldsView.insertSubview(textField, belowSubview: last) 
    let growth = last.frame.height + 8 // the 8 represents the top spacing between textFields 
    formViewHeight.constant += growth // increasing height of the view where the form is embeded 
    modelTextFieldsHeight.constant += growth // increasing height of the view where the textFields are embeded 
    UIView.animate(withDuration: 0.5) { 
     self.view.layoutIfNeeded() 
     textField.frame.origin.y += growth // moving new textField below the previous one 
    } 

    modelTextFields.append(textField) // array of UITextField to keep track of the textFields in screen 
}

和视图的对齐矩形： view-rectangles