How to set custom font for alert dialog in android?

To do this you use alert builder to build your alert. You then get the TextView from this alert and then you set the typeface for the alert.

AlertDialog dialog = new AlertDialog.Builder(this).setMessage("Hello world").show();
TextView textView = (TextView) dialog.findViewById(android.R.id.message);
Typeface face=Typeface.createFromAsset(getAssets(),"fonts/FONT"); 
textView.setTypeface(face);