Xamarin iOS subview created inside custom UIView class not showing up - uiview

Question

I have a custom UIView class, where I would like to add a bunch of subviews. This should be a simple task but I can't seem to figure out why my views are not showing up on the UI.
The examples and tutorials out there are pretty straight forward and I believe I have implemented my code correctly. I have added a breakpoint at AddSubview and the container has a size.
The UIViewController class already has a background image added it via the storyboard.
Can someone help me see what I'm probably missing? I know it's something small.
Below is my code:
The custom view class
public class RotaryWheel : UIView
{
int numberOfSections;
public RotaryWheel(CGRect frame,int sections): base(frame)
{
numberOfSections = sections;
DrawWheel();
}
public void DrawWheel()
{
// derive the center x and y
float centerX = (float)(Frame.Width / 2);
float centerY = (float)(Frame.Height / 2);
container = new UIView();
container.Frame = new RectangleF(centerX, centerY, 100, 100);
container.BackgroundColor = UIColor.White;
AddSubview(container);
}
}
The UIViewController class where I initialize the view
public partial class HomePageController : UIViewController
{
public override void LoadView()
{
base.LoadView();
rotaryWheel = new RotaryWheel(new CGRect(20f, (float)(View.Frame.Height / 2), (float)View.Frame.Size.Width, (float)View.Frame.Height / 2f), 7);
View.AddSubview(rotaryWheel);
}
}

Answer 1

First at all, refer to loadView(). As the documentation mentioned
If you want to perform any additional initialization of your views, do so in the viewDidLoad() method.
We should never initialize subviews in LoadView, so I try to move that code to viewDidLoad
public override void ViewDidLoad()
{
base.ViewDidLoad();
RotaryWheel rotaryWheel = new RotaryWheel(new CGRect(20f, (float)(View.Frame.Height / 2), (float)View.Frame.Size.Width, (float)View.Frame.Height / 2f), 7);
View.AddSubview(rotaryWheel);
}
But it looks like this, the subviews doesn't locate as expected.
After moving that code to ViewDidAppear, the problem disappeared.
public override void ViewDidAppear(bool animated)
{
base.ViewDidAppear(animated);
if(rotaryWheel == null){
rotaryWheel = new RotaryWheel(new CGRect(20f, (float)(View.Frame.Height / 2), (float)View.Frame.Size.Width, (float)View.Frame.Height / 2f), 7);
View.AddSubview(rotaryWheel);
}
}
Summary:
The real size of View comes out in method ViewDidAppear. If you don't use autoLayout , you should manage the View Frame carefully.
And about why you didn't see the subview, I guess you selected the iphone4 ,iPhone 5 or iPhone5S simulator for test , the screen width is 320, you create RotaryWheel with X= 20 , centerX is 300 in method LoadView, so it is displayed out of screen.