SignaturePad (Xamarin.Forms) not rendering on iOS(10) on a real device about signaturepad

[rjcollingham]

I have this in my AppDelegate.cs and it works great on iOS 10 iPhone 7

[Register("AppDelegate")]
public partial class AppDelegate : global::Xamarin.Forms.Platform.iOS.FormsApplicationDelegate {
public static Type dummyt = typeof(SignaturePad.Forms.iOS.SignaturePadRenderer); //<<-------

[voydz]

Hi @rjcollingham ,

thank you for your advice. I also tried this already (did not mention it in my initial post, though). Changing nothing in the result stated above. :(

[gtbuchanan]

It's due to linker settings in the build configuration. I actually had to create an instance of the renderer in AppDelegate to get it to work (pulled from this comment, but I found only the renderer is necessary). Just referencing the type as mentioned above didn't work for me.

var _ = new SignaturePad.Forms.iOS.SignaturePadRenderer();

I have confirmed this works in release mode with "Link SDK Assemblies" set. Hopefully, we won't have to resort to stupid hacks like this in the future.

[matthieugd]

@voydz did you find a solution ? I have the same problem and I also added the dummy code but still no luck. It's a Xamarin Forms project 2.3.3.175 with SignaturePad 1.4.0.

[balaameex]

HI,

I also faced the same problem, after adding the below code in App Delegate it solved the problem.
public static Type dummyt = typeof(SignaturePad.Forms.iOS.SignaturePadRenderer);

Thanks

[mattleibow]

Sometimes the linker links too much - and the linker is getting better.

One way that may be better is to use this type of "preserve":

static bool falseflag = false;
static AppDelegate ()
{
    if (falseflag) {
        var ignore = new SignaturePad.Forms.iOS.SignaturePadRenderer ();
    }
}

This code will never get executed, but the linker will never know that.

But some good news! This is no longer necessary in v2.0 (as yet unreleased). This is avoided since we are using the same assembly via bait-and-switch. Also, we are directly indicating to the linker that the particular view is using a particular renderer. So there is now a "hard" link between the view and the platform render.