UIPickerView not interactive - ios

Question

I have an application that from the main app "hamburger" menu, if an option is selected I want to show a PickerView for the user to select a number from.
Because it's needs to be accessible throughout the app from this menu I built the UIPickerView in the AppDelegate.cs (as that's where the UINavigationController code is and from that the menu).
Everything shows up correctly: User selected menu button -> menu displays -> User selects "Show Picker" button -> Picker displays with all items. But once the picker displays, you can't scroll the options, nor does the "Done" button I've added register clicks. In fact text fields from the ViewController behind this popup can be clicked on through the popup.
I'm not sure why this UIPickerView is non interactive, does anyone have some thoughts?
public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
// create a new window instance based on the screen size
window = new UIWindow(UIScreen.MainScreen.Bounds);
// instantiate the navigation controller
nav = new UINavigationController(new SplashController());
vwNav = new UIView(nav.NavigationBar.Bounds);
var pickerView = new UIPickerView(new CGRect(275f, (UIScreen.MainScreen.Bounds.Size.Height / 2) - (375f / 2), 275f, 375f));
pickerView.ShowSelectionIndicator = true;
var myPickerViewModel = new PickerViewModel(itemList);
pickerView.Model = myPickerViewModel;
myPickerViewModel.PickerChanged += (sender, e) => {
var temp = myPickerViewModel.SelectedItem;
};
// Set up toolbar
var toolbar = new UIToolbar();
toolbar.SizeToFit();
toolbar.Hidden = false;
UILabel titleLabel = new UILabel();
titleLabel.Text = "Select an Item";
titleLabel.Frame = new RectangleF(75, 13, 200, 20);
UIButton doneButton = new UIButton(UIButtonType.Custom);
doneButton.Frame = new RectangleF(40, 335, (float)200, 30);
doneButton.SetTitle("Done", UIControlState.Normal);
doneButton.TouchDown += (sender, e) =>
{
pickerView.Hidden = true;
};
toolbar.AddSubview(titleLabel);
toolbar.AddSubview(doneButton);
pickerView.AddSubview(toolbar);
pickerView.Hidden = true;
btnMenu = new UIButton(UIButtonType.Custom);
btnMenu.Frame = new CGRect(vwNav.Frame.Right - 45, 0, 45, nav.NavigationBar.Bounds.Height);
btnMenu.SetImage(imgMenu, UIControlState.Normal);
btnMenu.SetImage(imgMenu, UIControlState.Selected);
btnMenu.TouchUpInside += (object sender, EventArgs e) =>
{
UIAlertView alert = new UIAlertView();
alert.Title = "Settings";
alert.AddButton("Open PickerView");
alert.AddButton("Exit");
alert.Dismissed += delegate (object alertSender, UIButtonEventArgs args)
{
if (args.ButtonIndex == 0)
{
pickerView.Hidden = false;
}
else
return;
}
}
vwNav.AddSubviews(btnMenu, pickerView);
nav.NavigationBar.Layer.BorderWidth = 2f;
nav.NavigationBar.Layer.BorderColor = (UIColor.FromPatternImage(imgNavBar)).CGColor;
nav.NavigationBar.AddSubviews(vwNav);
// If you have defined a root view controller, set it here:
this.window.RootViewController = nav;
this.window.MakeKeyAndVisible();
return true;
}
I removed some of the unrelated code (a few nav.PushViewController() for different screens and other menu options) to keep it as clear as I could.

Answer 1

From your code, the frame of vwNav is nav.NavigationBar.Bounds, and the frame of pickerView is new CGRect(275f, (UIScreen.MainScreen.Bounds.Size.Height / 2) - (375f / 2), 275f, 375f), if you add pickView to vwNav, the pickerView is out of bounds of vwNav.
Remember that views don't receive touch events where they're outside the bounds of their superview.
That's the cause of your issue.
Solution:
I don't think you should built the UIPickerView in the AppDelegate.cs, create it in your ViewController instead.
You can also add buttons to Navigationbar in ViewController :
UIBarButtonItem btn = new UIBarButtonItem();
btn.Image = UIImage.FromFile("Image");
btn.Clicked += (sender, e) => { System.Diagnostics.Debug.WriteLine("show picker"); };
NavigationItem.RightBarButtonItem = btn;
And remember to add picker to the View of Viewcontroller.
Refer: uinavigationitem and add-uibarbuttonitem-to-navigation-bar-in-xamarin-ios
Feel free to ask me any question:).