getActivity() / context in a ViewHolder in Kotlin Android

In your implementation you can safely use Context from View provided to your OnClickListener

override fun onClick(p0: View) {
          Toast.makeText(p0.context, "${mCrime!!.mTitle} clicked!", Toast.LENGTH_SHORT / 2)
                .show()
    }

Just remember to set onclick:

fun bind(crime: Crime) {
           mCrime = crime
            val titleTextView = itemView.findViewById<TextView>(R.id.crime_title)
            val dateTextView = itemView.findViewById<TextView>(R.id.crime_date)
            titleTextView.text = mCrime!!.mTitle
            dateTextView.text = mCrime!!.mDate.toString()
            itemView.setOnClickListener(this)
}

Moreover all Kotlin classes are nested (static) by default. So your private class CrimeHolder is equivalent to private static class CrimeHolder in Java. That's why you don't have access to getActivity() from within CrimeHolder