Support external keyboard
See issue: https://github.com/mattermost/mattermost-mobile/issues/2512
When an external keyboard and an on-screen keyboard is used, the chat input text field looses focus as soon as the on-screen-keyboard is hidden, probably because hiding the keyboard changes the screen size and therefore triggers a redraw/relayout. I suggest to fix this.
Gregor Fuis commented
This where Mattermost Android app lacks the most. It is not done for Android tablets and it is impossible to use it with external keyboard. Please add support for this in the future.