No my friend its very simple, try using this:
AlertDialog alertDialog = new AlertDialog.Builder(AlertDialogActivity.this).create();
alertDialog.setTitle("Alert Dialog");
alertDialog.setMessage("Welcome to dear user.");
alertDialog.setIcon(R.drawable.welcome);
alertDialog.setButton(AlertDialog.BUTTON_POSITIVE, "OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(getApplicationContext(), "You clicked on OK", Toast.LENGTH_SHORT).show();
}
});
alertDialog.show();
This tutorial shows how you can create custom dialog using xml and then show them as an alert dialog.