Page title construction in RouterLayout issue

Description of the bug

After these changes in Vaadin Flow

https://github.com/vaadin/flow/pull/13825/files#diff-32470b1fe06ff7a0966c7da3ded43f636d1a013b78ff34b06049c7915c4c359cR238

It’s not possible to construct custom page title outside of each view. Navigation lifecycle always rewrites title at the end, so it seems that there is no places left where we can call Page.setTitle("custom title").

Expected behavior

It’s must be possible to set custom page title after navigation finished

Minimal reproducible example

Minimal example from the real app: https://github.com/gigi/vaadin-23-pagetitle-issue

Main idea is to avoid service dependencies coupling and delegate control of common UI elements to layouts.

So there is custom PageChangedEvent event which can be used for updating layout menu, breadcrumbs construction, setting page title etc. This event is fired in After Navigation stage. Before these changes it was possible to construct page title and set it by hand: https://github.com/gigi/vaadin-23-pagetitle-issue/blob/main/src/main/java/com/example/demo/layout/BasicLayout.java#L50

Possible solutions:

• Add support of HasDynamicTitle in the RouterLayout that has higher priority than Router’s getPageTitle or vice versa
• Concatenate page title somewhere in response listeners (I don’t know where exactly and how to handle title template properly)
• Inject necessary layout dependencies in each view and construct title in getPageTitle (quite annoying)

Versions

• Vaadin: 23.1.0.rc1
• Flow: 23.1.0.rc2
• Java: BellSoft 17.0.3
• OS: x86_64 Mac OS X 12.3.1
• Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.64 Safari/537.36

[MarcinVaadin]

For me it makes sense to use HasDynamicTitle from first available parent layout if it implements such. It is easily accessible from active router target chain.

As for overriding title which was set during AfterNavigation - we could introduce a flag that will be set after title has been already set and will prevent triggering default AbstractNavigationStateRenderer.updatePageTitle.

After above change view updates title by PageChangedEvent on afterNavigation and Flow reads a title value from first parent layout.

Thanks @gigi for example project, it helped a lot.

[vaadin-bot]

This ticket/PR has been released with Vaadin 24.0.0.alpha6 and is also targeting the upcoming stable 24.0.0 version.