kotlin unimplemented exception code example

Example: An operation is not implemented: Not yet implemented

just remove TODO( ... ) from your onClickListener:

override fun onClick(v: View?) {
    // No TODO here
    when (v?.id) {
        ...
    }
}
TODO(...) is Kotlin function which always throws NotImplementedError. If you want to mark something with TODO but to not throw exception - just use TODO with comments:

override fun onClick(v: View?) {
    //TODO: implement later
    when (v?.id) {
        ...
    }
}