feat: Auto-hide Image Viewer toolbar

[tinsukE]

When viewing an Image, it is not straightforward to understand that tapping on it will hide the toolbar and alt sheet, and those elements might get in the way of them viewing the full image.

Automatically hiding the toolbar and alt sheet after some short time might help the user two ways:

1. Get out of their way when they're viewing an image with an aspect ratio so that those elements are on top of it.
2. Showing them that those elements are hide-able, which might nudge into tapping to restore them and, consequently, learn about the "tap to hide/show" feature.

Interacting with the alt sheet cancels the auto-hide.

Fixes #505

[CLAassistant]

All committers have signed the CLA.

[tinsukE]

I wanted to also cancel the auto-hide behavior in case the toolbar is interacted with. I have those changes here, but I couldn't find a way to listen to opening the overflow menu, so I refrained from adding those changes to this PR: tinsukE#1

[nikclayton]

Thanks for the PR. Left some general comments above.

I wanted to also cancel the auto-hide behavior in case the toolbar is interacted with. I have those changes here, but I couldn't find a way to listen to opening the overflow menu, so I refrained from adding those changes to this PR: tinsukE#1

If you make the Fragment class extend from MenuProvider then do this in onViewCreated:

        requireActivity().addMenuProvider(this, viewLifecycleOwner, Lifecycle.State.RESUMED)

then onPrepareMenu will be called just before the toolbar menu is displayed (https://developer.android.com/reference/androidx/core/view/MenuProvider#onPrepareMenu(android.view.Menu)), and I think that's the right place to cancel the auto-hiding.

[tinsukE]

@nikclayton I have updated the PR according to the discussions.

[tinsukE]

If you make the Fragment class extend from MenuProvider then do this in onViewCreated:

        requireActivity().addMenuProvider(this, viewLifecycleOwner, Lifecycle.State.RESUMED)

then onPrepareMenu will be called just before the toolbar menu is displayed (https://developer.android.com/reference/androidx/core/view/MenuProvider#onPrepareMenu(android.view.Menu)), and I think that's the right place to cancel the auto-hiding.

@nikclayton Thanks for the tip! I found that MenuProvider#onPrepareMenu(android.view.Menu) is also called when the Toolbar is being setup, and I wouldn't want to cancel the auto-hiding then, but I managed a workaround creative solution for it.

Let me know if If you'd prefer to leave that change as a second PR for when this is merged, or if I should batch them together.

[nikclayton]

Let me know if If you'd prefer to leave that change as a second PR for when this is merged, or if I should batch them together.

I'll get this merged (so it can go out in the next Pachli Current) and if you can do the followup in a new PR that'd be great. Thanks for the PR!