Android softkeyboard support

[jb55]

For input on android, we need to pop up the keyboard. This isn't directly supported by egui, since egui doesn't handle such things. egui delegates such tasks to winit, but winit does not support it yet.

External tracking issues:

• handle input method visibility for android emilk/egui#3890
• SoftInput (Software Keyboard) support rust-windowing/winit#1823
• display soft keyboard input in Android emilk/egui#2975
• Can't summon soft_input with egui + winit + wgpu rust-mobile/android-activity#44
• Input method (soft keyboard) support rust-mobile/android-activity#24
• Expose Rust API for input method handling via the GameTextInput library rust-mobile/android-activity#18
• Add android ime support rust-windowing/winit#2993

Progress in this area:

• Can't summon soft_input with egui + winit + wgpu rust-mobile/android-activity#44 (comment) by @lucasmerlin

Our progress:

• https://github.com/damus-io/android/issues/74
• Sidequest: add GameActivity_setImeEditorInfo support to android-activity #171
• Update IME/soft keyboard braches for more recent versions of egui/winit #187
• Android build files #189
• Switch to GameActivity #190

[jb55]

I looked into this all yesterday. It looks like we might need to switch over to GameActivity to get this working. There is some initial work from @rib in android-activity (rust-mobile/android-activity#24) for soft keyboard + GameActivity, but it looks like we'll will still need winit/egui support. There are some demos by @lucasmerlin at https://github.com/lucasmerlin/rust-android-examples/tree/ime_support_showcase/agdk-eframe which demo this in egui.

The current build tooling we're using assumes its a NativeActivity, I have yet to get GameActivity working. It seems there are many build tools: cargo-apk (what we're using now), cargo-ndk, cargo-xbuild, cargo-mobile2. I'm not sure what to use. The GameActivity demos use cargo-ndk but it requires some gradle step which I have yet to get working.

Somewhat surprised the rust mobile ecosystem still can't present a keyboard for input, oh well, I guess banging my head against this a bit more is easier than building an entirely new android kotlin codebase from scratch.

[lucasmerlin]

I can report that I'm still using the method from the showcase in my app and I regularly update my fork of winit and egui with the keyboard changes to the newest versions.

The current versions of my fork are here:

https://github.com/lucasmerlin/egui/tree/hp_improvements_0.26

https://github.com/lucasmerlin/winit/tree/hp-fixes-0.29.x

They also contain changes unrelated to keyboard input, but maybe it will still be helpful.

[jb55]

I saw those! Thank you! I will try to get these working.

[jb55]

Since this is a large task I will split it into specific deliverables for this sprint

[alltheseas]

@jb55 with issues transferred over from old android repo to notedeck repo, I am adding an 'android' label to every android specific issue

[alltheseas]

@ksedgwic