ios视图在导航到其他屏幕后消失

我在故事板上有一个自定义视图，它充当工具栏。这个视图有三个按钮，我为ViewDidLoad中的每个按钮定义了自定义视图

当我导航到另一个视图，然后向后移动到此原始屏幕时，这些按钮上的文本和图像都会丢失。只有一个空的黑酒吧。某些设备会出现这种情况，但视图显示得很好，在其他设备上永远不会消失

我所尝试的：

• 我已在ViewWillDisplay中将这些按钮的隐藏属性显式设置为false
  btn1.Hidden=false； btn2.Hidden=false； btn3.Hidden=false

• 我还尝试在ViewWillDisplay而不是ViewDidLoad中定义按钮，看看这是否解决了问题。它们仍然消失

下面是我的代码：

  public override void ViewWillAppear(bool value)
    {
        try
        {
            base.ViewWillAppear(value);


            //icon setup

            //the space between the image and modelFilterText
            var spacing = 0.3f;

            var icon1 = UIImage.FromBundle("Icons/Home/icon1.png");


            btn1.SetImage(icon1, UIControlState.Normal);
            btn1.SetTitle("ONE", UIControlState.Normal);
            btn1.SetTitleColor(UIColor.LightGray, UIControlState.Normal);
            btn1.Font = UIFont.FromName("BankGothicBT-Light", 12f);
            btnRequest.TouchUpInside += (object sender, EventArgs e) =>
            {
                NavigationItem.BackBarButtonItem = new UIBarButtonItem("", UIBarButtonItemStyle.Plain, null);

                NavigationController.PushViewController(view1, true);
            };

            // lower the modelFilterText and push it left so it appears centered 
            //  below the image

            var imageSize = btn1.ImageView.Image.Size;
            btn1.TitleEdgeInsets = new UIEdgeInsets(0.0f, -imageSize.Width, -(imageSize.Height + spacing),
                0.0f);

            // raise the image and push it right so it appears centered
            //  above the modelFilterText

            var titleSize = btn1.TitleLabel.Text.StringSize(btn1.TitleLabel.Font);
            btn1.ImageEdgeInsets = new UIEdgeInsets(-(titleSize.Height + spacing), 0.0f, 0.0f,
                -titleSize.Width);

            //Second Icon
            var icon2 = UIImage.FromBundle("Icons/Home/icon2.png");

            btn2.SetImage(icon2, UIControlState.Normal);
            btn2.SetTitle("TWO", UIControlState.Normal);
            btn2.SetTitleColor(UIColor.LightGray, UIControlState.Normal);
            btn2.Font = UIFont.FromName("BankGothicBT-Light", 12f);

            btn2.TouchUpInside +=
                (object sender, EventArgs e) =>
            {
                NavigationItem.BackBarButtonItem = new UIBarButtonItem("", UIBarButtonItemStyle.Plain, null);
            };

            // lower the modelFilterText and push it left so it appears centered 
            //  below the image

            var imgSize = btn2.ImageView.Image.Size;
            btn2.TitleEdgeInsets = new UIEdgeInsets(0.0f, -imgSize.Width, -(imgSize.Height + spacing), 0.0f);

            // raise the image and push it right so it appears centered
            //  above the modelFilterText

            var titleLength = btn2.TitleLabel.Text.StringSize(btn2.TitleLabel.Font);
            btn2.ImageEdgeInsets = new UIEdgeInsets(-(titleLength.Height + spacing), 0.0f, 0.0f,
                -titleLength.Width);


            //Third Icon
            var icon3 = UIImage.FromBundle("Icons/Home/icon3.png");

            btn3.SetImage(icon3, UIControlState.Normal);
            btn3.SetTitle("THREE", UIControlState.Normal);
            btn3.SetTitleColor(UIColor.LightGray, UIControlState.Normal);
            btn3.Font = UIFont.FromName("BankGothicBT-Light", 12f);

            btn3.TouchUpInside += (object sender, EventArgs e) =>
            {

                NavigationItem.BackBarButtonItem = new UIBarButtonItem("", UIBarButtonItemStyle.Plain, null);

                NavigationController.PushViewController(view3, true);
            };


            // lower the modelFilterText and push it left so it appears centered below the image

            var imagSize3 = btn3.ImageView.Image.Size;
            btn3.TitleEdgeInsets = new UIEdgeInsets(0.0f, -imagSize3.Width, -(imagSize3.Height + spacing),
                0.0f);

            // raise the image and push it right so it appears centered
            //  above the modelFilterText

            var titleLength3 = btn3.TitleLabel.Text.StringSize(btn3.TitleLabel.Font);
            btn3.ImageEdgeInsets = new UIEdgeInsets(-(titleLength3.Height + spacing), 0.0f, 0.0f,
                -titleLength3.Width);


        }
        catch (Exception ex)
        {
            Console.WriteLine("View will appear error " + ex.Message + ex.StackTrace);
        }

    }

---

按钮第一次出现并正确绘制。然而，当我离开这个页面并返回到它时，在底部只有一个黑色的视图。没有按钮。

我知道按钮实际上不会消失。它们被iOS工具栏遮住了

例如，如果我导航到具有iOS工具栏的屏幕，然后向后导航到此主页，则此后所有其他屏幕的

NavigationController.SetToolbarHidden

属性都设置为true

所以我所需要做的就是在这个主页的viewwillbeen中将这个设置为false，这样它就不会模糊我的自定义视图

NavigationController.SetToolbarHidden(true,false)