推送UIViewController的视图没有父

Question

我有一个

1- UIView

 class AddNewsView : UIView
        {
            UIButton addButton;
            Database db = new Database(Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), "NewsDb.sqlite"));
            public AddNewsView()
            {
                //declaring button
                addButton = new UIButton(UIButtonType.RoundedRect);
                addButton.SetTitle("Add news", UIControlState.Normal);
                addButton.SizeToFit();
                addButton.TouchUpInside += addButtonClicked;
                Add(addButton);

                //adding constraints
                TranslatesAutoresizingMaskIntoConstraints = false;
                AddConstraint(NSLayoutConstraint.Create(
                    addButton,
                    NSLayoutAttribute.Top,
                    NSLayoutRelation.Equal,
                    this,
                    NSLayoutAttribute.Top,
                    1f, 5f
                    ));

                AddConstraint(NSLayoutConstraint.Create(
                    addButton,
                    NSLayoutAttribute.Width,
                    NSLayoutRelation.Equal,
                    this,
                    NSLayoutAttribute.Width,
                    0.5f, 0f
                    ));

                AddConstraint(NSLayoutConstraint.Create(
                    addButton,
                    NSLayoutAttribute.Height,
                    NSLayoutRelation.Equal,
                    this,
                    NSLayoutAttribute.Height,
                    0.5f, 0f
                    ));

                AddConstraint(NSLayoutConstraint.Create(
                    addButton,
                    NSLayoutAttribute.CenterX,
                    NSLayoutRelation.Equal,
                    this,
                    NSLayoutAttribute.CenterX,
                    1f, 0f
                    ));

                AddConstraint(NSLayoutConstraint.Create(
                    addButton,
                    NSLayoutAttribute.CenterY,
                    NSLayoutRelation.Equal,
                    this,
                    NSLayoutAttribute.CenterY,
                    1f, 0f
                    ));
            }

            void addButtonClicked(object sender, EventArgs ea)
            {
                var news = new News();
                news.Title = "News 1";
                news.Text = " This is the text of news 1 ";
                db.InsertNewsAsync(news);
                new UIAlertView("Alert", "News added", null, "Dismiss", null).Show();
            }

        }

2- UIViewController

    class NewsViewController : UIViewController
        {
            string path = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), "NewsDb.sqlite");
            public override void ViewDidLoad()
            {
                base.ViewDidLoad();

                //tableview under navbar
                View.TranslatesAutoresizingMaskIntoConstraints = false;
                EdgesForExtendedLayout = UIRectEdge.All;
                AutomaticallyAdjustsScrollViewInsets = true;
                ExtendedLayoutIncludesOpaqueBars = true;

                //Adding news table
                var table = new UITableView(View.Bounds);
                table.Source = new TablesSources(new Database(path));
                Add(table);

                //Adding + button
                UIBarButtonItem plusButton = new UIBarButtonItem(UIBarButtonSystemItem.Add);
                plusButton.Clicked += addButtonClicked;
                NavigationItem.RightBarButtonItem = plusButton;
            }
            void addButtonClicked(object sender , EventArgs ea)
            {


NavigationController.PushViewController(new NewsAdditionViewController(), true);

            }
        }

3- UIViewController由前一个控制器推送

class NewsAdditionViewController : UIViewController
    {
        AddNewsView newsAdd;
        public override void ViewDidLoad()
        {
            base.ViewDidLoad();
            newsAdd = new AddNewsView();
            View.BackgroundColor = UIColor.Black;
            View.TranslatesAutoresizingMaskIntoConstraints = false;

            EdgesForExtendedLayout = UIRectEdge.All;
            AutomaticallyAdjustsScrollViewInsets = true;
            ExtendedLayoutIncludesOpaqueBars = true;

            //adding subview
            newsAdd.BackgroundColor = UIColor.Orange;
            View.AddSubview(newsAdd);
            //setting constraints
            View.AddConstraint(NSLayoutConstraint.Create(
                newsAdd,
                NSLayoutAttribute.Width,
                NSLayoutRelation.Equal,
                View,
                NSLayoutAttribute.Width,
                0.5f, 0f
                ));

            View.AddConstraint(NSLayoutConstraint.Create(
                newsAdd,
                NSLayoutAttribute.Height,
                NSLayoutRelation.Equal,
                View,
                NSLayoutAttribute.Height,
                0.5f,0f
                ));

            View.AddConstraint(NSLayoutConstraint.Create(
                newsAdd,
                NSLayoutAttribute.CenterX,
                NSLayoutRelation.Equal,
                View,
                NSLayoutAttribute.CenterX,
                1f, 0f
                ));

            View.AddConstraint(NSLayoutConstraint.Create(
                newsAdd,
                NSLayoutAttribute.CenterY,
                NSLayoutRelation.Equal,
                View,
                NSLayoutAttribute.CenterY,
                1f, 0f
                ));

        }
    }

问题是 NewsAdditionViewController 视图没有占用屏幕，我希望它占据全屏，那么问题是什么呢？

Answer 1

通过设置

修复

    View.TranslatesAutoresizingMaskIntoConstraints = true;

在NewsAdditionViewController中