Set toolbar title

In kotlin

(activity as? AppCompatActivity)?.supportActionBar?.title = "title"

Edit: Added null safe operator ? to avoid NullPointer in case ActionBar not available

Change it to

((AppCompatActivity)getActivity()).getSupportActionBar().setTitle("Home");

You needed to tell the activity it is an AppCompatActivity.

Then you use getActivity() to get the main activity since you are in a fragment.

Then just set the title as usual.