Question

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

当我导航到其他视图，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丢失了。只有一个空的黑条。对于某些设备会发生这种情况，但视图显示得很好，并且永远不会在其他设备上消失。

我尝试过的事情：

我在ViewWillAppear
中明确将这些按钮的隐藏属性设置为false
btn1.Hidden = false; btn2.Hidden = false; btn3.Hidden = false;
我还尝试在ViewWillAppear中定义按钮而不是ViewDidLoad，看看是否能解决问题。他们仍然消失。

以下是我的代码：

  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);
        }

    }

按钮出现并在第一次正确绘制。然而，在我离开这个页面然后回到它之后，底部只有一个黑色的视图。没有按钮。

Answer 1

我了解到按钮实际上并没有消失。它们被iOS工具栏遮挡。

例如，如果我导航到具有iOS工具栏的屏幕，然后向后导航回此主页，则此后所有其他屏幕的NavigationController.SetToolbarHidden属性设置为true。

所以我需要做的是在本主页的ViewWillAppear中将其设置为false，因此它不会遮挡我的自定义视图。

NavigationController.SetToolbarHidden(true,false)

导航到其他屏幕后，ios View消失

1 个答案: