Responding to Dynamic Text changes at runtime

Question

I'm working on adding some better accessibility support to a Xamarin.Forms application, including font scaling. For test purposes, I have made a new solution with a very simple layout:

<StackLayout Padding="20">
    <Label Text="Small" FontSize="Small"/>
    <Label Text="Medium" FontSize="Medium"/>
    <Label Text="Large" FontSize="Large"/>
    <Label Text="BodyStyle" Style="{DynamicResource BodyStyle}"/>
    <Label Text="Font Size 24" FontSize="24"/>
</StackLayout>

On Android, when I go to Settings, change the font size, and return to the app, all 5 labels change in response to the accessibility settings. On iOS, only the BodyStyle changes unless I swipe-kill and reopen the app. Is there an AppDelegate override or something I can add so I can respond to accessibility changes without killing the app or needing dynamic resources for everything?

Answer 1

I've settled on using the built-in Device Styles for now.

Answer 2

Hello,

Welcome to Microsoft Q&A!

You can simply use the following code in iOS project to detect when the accessibility settings has been changed .

   Foundation.NSObject observerToken  
                = UIApplication.Notifications.ObserveContentSizeCategoryChanged(  
                    (s, e) =>  
                    {   
                           //use messaging center  
                    });  

Then you can send message to forms project to rebuild your UI.

Refer to https://forums.xamarin.com/discussion/186212/how-to-handle-dynamic-type-the-larger-text-accessibility-option-on-ios-without-re-starting-app#latest .

---

If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.