Use the MoreNavigationController DidShowViewController callback for shell sections

[Dresel]

Description of Change

When SelectedViewController is called for MoreNavigationController, register for DidShowViewController to make it possible to set ShellItem.CurrentItem when selecting shell sections aggregated in more tab. Implementation is based on this SO thread.

Automated test is skipped because lack of information (is there any guidance available?) of how to setup UI tests for XF.

Issues Resolved

• fixes [Bug] [Shell] [iOS] ShellItem.CurrentItem not set when selecting shell section aggregated in more tab #6784

API Changes

None

Platforms Affected

• iOS

Testing Procedure

Check #6784.

PR Checklist

• Has automated tests
• Rebased on top of the target branch at time of PR
• Changes adhere to coding standard

[rmarinho]

/azp run

[azure-pipelines]

No pipelines are associated with this pull request.

[samhouts]

failing unit test

[samhouts]

Xamarin.Forms.Core.UnitTests.ShellTests.NavigationBetweenShellContentsPassesQueryString
System.ArgumentException : Duplicated Route: "details"

[PureWeen]

@Dresel can you rebase against master? That should fix the unit test error

[Dresel]

Rebase done

[PureWeen]

@Dresel I ran into a slight issue while testing this

it looks like after you select the item from the more list the first time then it won't reopen the more list when navigating back to it unless you click it twice.

Apologies this took so long to review. Let me know if you don't have time and I can look into this issue.

FYI I also rebased this PR to the latest 4.3.0 so it would build.

As far as UI tests if you want to give it a try you can see an example of a Shell UI tests here

Xamarin.Forms/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/ShellTitleView.cs

Line 19 in 14555f7

public class ShellTitleView : TestShell

[Dresel]

Currently busy but I'll be able to tackle this latest end of this month

[woutervanoorschot]

@PureWeen I think that this is the correct behaviour. At least on iOS it is the default behaviour that a tab stays the same (also within the more page) when navigated to and from. If a page has been opened in the more tab, navigating to another tab and returning to it should return you to the opened page. The second tap returns you to the root of the tab (in the more tab: the list of pages).

This works the same as in other tabs, if you navigate within a tab it stays the same after navigating between tabs. When tapping on a tab which is selected, navigationpage within the tab goes to the root page.

Anyway, very nice that someone is looking after this, as it seems to fix the very long standing issue of the more tab in xamarin.

[Dresel]

Sorry, took me longer than expected.

@Dresel I ran into a slight issue while testing this

it looks like after you select the item from the more list the first time then it won't reopen the more list when navigating back to it unless you click it twice.

This can be "corrected" by calling PopToRootViewController on the MoreNavigationController.

For consistency we should also set CustomizableViewControllers to an empty array (or null) to avoid the "Edit" button on top of the MoreNavigationController:

This property controls which items in the tab bar can be rearranged by the user. When the user taps the More item on the tab bar view, a custom interface appears displaying any items that did not fit on the main tab bar. This interface also contains an Edit button that allows the user to rearrange the items. Only the items whose associated view controllers are in this array can be rearranged from this interface. If the array is empty or the value of this property is nil, the tab bar does not allow any items to be rearranged.

Let me know if you want this in a separate PR or if I can combine it with this one.

I have rebased and pushed latest changes, let me know what you think.

I'm now working on a UI test case for that, it's a pity that this does not work with remote debugger on windows...

[woutervanoorschot]

I think you should combine it in this PR, as it creates inconsistent behavior across platforms if the edit button is visible (as you said already). Just my 2 cents

Great work!

[Dresel]

UI test added, let me know if this fits.

[Dresel]

Could not reproduce the failing UI tests (SDK 12.4 build, iPhone X 11.4 simulator).

[woutervanoorschot]

@PureWeen any chance this can be included in Xamarin Forms 4.5?