How to make a custom softkeyboard in Android which can be also operated by hardkey input like Up, Down, Left, Right and Ok

Question

I have created a custom soft Keyboard in Android by following https://stackoverflow.com/a/44939816/6680949 link.

Now i want to add a feature to it. Custom soft keyboard need to be operated by a hardkey input like Up, Down, Left, Right and Ok button. All the hardkey events are received as broadcast event.

I would like to know how can i focus the key pragmatically based on the hardkey input like Up, Down, Left, Right and select a key on Ok hardkey input.

Also any leads to implement this will be helpful.