How to implement a custom AlertDialog View

Question

In the Android docs on AlertDialog, it gives the following instruction and example for setting a custom view in an AlertDialog:

If you want to display a

Answer 1

android.R.id.custom was returning null for me. I managed to get this to work in case anybody comes across the same issue,

AlertDialog.Builder builder = new AlertDialog.Builder(context)
            .setTitle("My title")
            .setMessage("Enter password");
final FrameLayout frameView = new FrameLayout(context);
builder.setView(frameView);

final AlertDialog alertDialog = builder.create();
LayoutInflater inflater = alertDialog.getLayoutInflater();
View dialoglayout = inflater.inflate(R.layout.simple_password, frameView);
alertDialog.show();

For reference, R.layout.simple_password is :