Focus / making the editor first responder

[gmckenzi]

I'm using this in a SwiftUI project and the only thing I haven't been able to figure out is how to programmatically set focus into the editor.

I have found StackOverflow posts that suggest WKWebView intentionally tries to prevent automatically setting focus without user interaction.

Is there a way in MarkupEditor that I can have it assume focus? My scenario is that I present the editor in a sheet and want the user to be able to start typing in the editor without having to tap into the editor first.

[gmckenzi]

I see there is a bunch of swizzling code for focus in MarkupWKWebView that was commented out on Sep 5. If I restore that code and call showKeyboard() from makeUIView in the UI representable class, the editor gets focus and the keyboard appears.

I expect there was a good reason for commenting out this code and losing the functionality, but I'd love to know why or what the risks are of restoring this code.

[stevengharris]

I did a lot of work on this issue that is still in main right now. Basically you can tell the MarkupEditor which view should be the firstResponder by its id:

MarkupEditor.firstResponder = <The String id of the MarkupWKWebView>

In the demos, the id is set to "Document" when the MarkupEditorView is created:

MarkupEditorView(markupDelegate: self, html: $demoHtml, resourcesUrl: resourcesUrl, id: "Document")

In the app I'm using MarkupEditor with, I have a unique id for the model-type object that holds onto the HTML I feed to the MarkupEditor.

Behind the scenes, the MarkupWKWebView observes the ObservedFirstResponder and responds:

/// Monitor the setting for MarkupEditor.observedFirstResponder, and set this MarkupWKWebView to be the first responder
/// when the id matches.
///
/// Becoming the first reponder also means that focus and selection state are set properly.
private func observeFirstResponder() {
    firstResponder = MarkupEditor.observedFirstResponder.$id.sink { [weak self] selectedId in
        guard let selectedId, let self, self.id == selectedId else {
            return
        }
        self.becomeFirstResponderIfReady()
    }
}

Main should be stable and I hope (but tbh not absolutely certain) compatible with the Beta release.

[gmckenzi]

Awesome -- I'll point my package ref to main and give this a go. Thank you for such a prompt and detailed reply!

[stevengharris]

Sorry, I think I sent you on a wild goose chase with main as opposed to the swizzling methods you found earlier. The work I did on firstResponder was useful and dealt with the case of it not working right because a view was not yet ready. In my usage, I have a List of MarkupWebViews, and I need to scroll to a particular one and make sure the insertion-point caret is showing properly, which is not the issue you're having. I even removed the swizzling methods for keyboard interaction from main because I figured they were not needed!!!

I think the reason I commented that code out was because, as you said, Apple mostly doesn't want you to be bringing up the keyboard without the user selecting something. Plus, in my own case, I want the view to open without the keyboard when on iOS, because I want it to be readable and scrollable without the keyboard covering the screen. I still think that will be the default case, but I can see adding a setting to make it optional, and then calling showKeyboard() at the right place when the option is set. That work would amount to adding a new static to MarkupEditor (so, for example, it could be set in your AppDelegate or someplace handy), and then gating the call to showKeyboard with a test on that setting. I'm not completely certain that makeUIView is the right place, but maybe. I might prefer it on a MarkupDelegate callback.

If you want to do that as a PR, I'd love to put it in. (FWIW, it would be easiest for me on main.) Otherwise, we can leave this open and I will try to deal with it at some point relatively soon.

I appreciate your raising the issue and can see how this can be very important. If you don't file a PR, please add any additional info about how you dealt with it if you think it will be useful to me and others.

Also, please note #89, which you will need to work around for now.

[gmckenzi]

Thank you for all this info, and apologies for my delay in responding. I've been heads-down for the last little while.

Over the next week I'll focus on implementing this and reach out for feedback and/or submit a PR.

[anishjain123]

Has this been resolved? @gmckenzi @stevengharris

[stevengharris]

I haven't been able to spend any time on it. Have you tried what @gmckenzi suggested in #88 (comment)?

[JohnKuan]

Hi @stevengharris, not sure if this is related.

In my use case, I have other UITextFields above the MarkupEditor. The MarkupEditor is the entire space below. When I try to tap on the space except the topmost line, it does not respond to being a first responder. However when I tap on the top most line, it becomes the first responder. This only happens for the first time, and after that it works properly.

RPReplay_Final1692860986.mov