Feature/add_Vietnamese_Telex

[chihung93]

Hi @tibbi , I have finished the support of Vietnamese - Telex

Feature:

1. Added a Vietnam Telex in the Setting screen
2. Added the telex extension (Reference: https://github.com/florisboard/florisboard/blob/aa00eb6e79081fb602c68e55b7d5e80bfe2ae322/app/src/main/assets/ime/keyboard/org.florisboard.composers/extension.json#L17)
3. Using telex in Edit text. Thanks.

Demo:

Demo_telex.webm

[chihung93]

Thanks for your feedback. I have fixed all issues. @tibbi

[tibbi]

looks great, thanks :)

[tranhongs0n]

@chihung93, @tibbi Thank you all for adding Vietnamese to this app, but there are still many bugs and I almost can't use this keyboard to type Vietnamese. I hope everyone will consider testing it more thoroughly.

[tibbi]

ok, will try improving it once we find someone that has experience with it :)

[dmitriy-chernysh]

I see Vietnamese key layout (xml/keysletters....xml) is missing in the app https://github.com/SimpleMobileTools/Simple-Keyboard/issues/256