[macOS] Provide a way to close the accent panel programmatically

[angelosilvestre]

Is there an existing issue for this?

• [X] I have searched the existing issues
• [X] I have read the guide to filing a bug

Use case

In super_editor, we handle text input by using both TextInputClient (with delta model enabled) and FocusNode's onKey.

We need to handle key events because some operations generates text editing deltas and others don't. For example, typing a character generates a TextEditingDeltaInsertion, but pressing BACKSPACE don't. Because of that, we handle the BACKSPACE key event to delete a character upstream.

By handling the BACKSPACE key event we have the following issue:

After pressing and holding a letter, macOS shows the accent panel:

By pressing BACKSPACE, the panel should close. However, as we handled the BACKSPACE key event, the panel stays open.

Proposal

Provide a method in TextInputConnection so we can close the accent panel after handling the key event.

[justinmc]

@cbracken Do you know if Flutter is calling some native Mac API to show this accent menu in the engine? If so then it shouldn't be too hard to expose this programmatically to the framework.

[flutter-triage-bot[bot]]

The triaged-design label is irrelevant if there is no team-design label or fyi-design label.

[cbracken]

This is handled entirely by macOS (other than all the work that @LongCatIsLooong did to ensure we're not stealing input for arrow keys/numbers). I suspect that dismissing this should be identical to dismissing the IME composing candidates list. I suspect if there's a means to do that, we'll find it in InputMethodKit. Maybe [InputMethodController hidePalettes]?

[justinmc]

@cbracken Thank you for the insight here!

[LongCatIsLooong]

Does it work if you handle DeleteCharacterIntent instead of intercepting key events? As @cbracken mentioned the IME should be the one handling the accent menu, and if the backspace key event is intercepted by FocusNode.onKey, then the IME won't be able to close it.

[angelosilvestre]

@LongCatIsLooong Using DeleteCharacterIntent doesn't work because the Shortcuts widget also intercepts key events on FocusNode.onKey.

[LongCatIsLooong]

On macOS if I remember correctly it's not using a Shortcuts widget. Shortcuts uses / depends on Intent/Actions stuff, not the other way around.

[flutter-triage-bot[bot]]

The triaged-desktop label is irrelevant if there is no team-desktop label or fyi-desktop label.