Improving the operation of PresentationControllers

[dimonovdd]

Description of Change

Using Rg.Plugins.Popup and Essentials together, I noticed some problems:

• Closing Popups closes pickers and etc., but the tasks remain not finished.
• We don't have the option to specify a UIViewController before opening pickers

This is due not only to Rg.Plugins.Popup, but also to any projects that use custom controllers for rendering pages.

API Changes

Added:

public static partial class Platform
{
    public static void Init(Func<UIViewController> getCurrentUIViewController)
}

Behavioral Changes

• All tasks will be finished when the controller is closed
• Ability to change the parent controller for pickers

PR Checklist

• Has tests (if omitted, state reason in description)
• Has samples (if omitted, state reason in description)
• Rebased on top of main at time of PR
• Changes adhere to coding standard
• Updated documentation (see walkthrough)

[dimonovdd]

Experimentally, I found out that DidDismiss method is not always called when closing parent controllers. And this is probably the only workaround to finish a TaskCompletionSource.

[mattleibow]

@dimonovdd What would be a use case for this? Just for reference.

[dimonovdd]

There was such a case in my application:

1. A popup appears
2. FilePicker appears
3. The popup closes and it closes the picker

because the picker was opened from the popup controller, and not from main navigation controller

[dimonovdd]

Will it be merged? It is a big problem. It has been fixed in many libraries for example in userdialogs:

Nothing is necessary any longer as of v4.x. There is an Init function for iOS but it is OPTIONAL and only required if you want/need to control
the top level viewcontroller for things like iOS extensions. Progress prompts will not use this factory function though!

Usage example:

[assembly: ExportRenderer(typeof(NavigationPage), typeof(CustomNavigationRenderer))]

public class CustomNavigationRenderer : NavigationRenderer
{
    public static CustomNavigationRenderer LastController { get; private set; }
    
    public override void ViewDidLoad()
    {
        base.ViewDidLoad();
        LastController = this;
    }
}

static UIViewController? GetTopViewController()
{
    if (!(PopupNavigation.Instance?.PopupStack?.Any() ?? false))
        return Xamarin.Essentials.Platform.GetCurrentUIViewController();

    return CustomNavigationRenderer.LastController?.ViewControllers?.LastOrDefault();
}

public override bool FinishedLaunching(UIApplication app, NSDictionary options)
{
    \\...
    UserDialogs.Init(GetTopViewController);
    \\...
}