Random XML Layout on button click

I have 20 XML layouts. What I want to happen is to show random xml layouts when the button is clicked. I tried and read same problem as mine but i didnt worked.

This is code in Level1 class(the same pattern applies for the rest of the classes)

    public void checkAnswer()
    {   String answer=answerText.getText().toString();  

        if(isCorrect(answer))
        {       

            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setTitle("Congratulations! You will receive P10!");
            builder.setMessage("Did you know that Former bla bla bla Did you know that Former bla bla bla Did you know that Former bla bla bla");
            builder.setIcon(android.R.drawable.btn_star_big_on);
            builder.setPositiveButton("OK",new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {

                String userData=scoreTxt.getText().toString();
                int userNumber=Integer.parseInt(userData);

                Intent intent=new Intent(Luzon1.this, Luzon2.class);
                intent.putExtra("parameter name", userNumber);
                startActivity(intent);
                Luzon1.this.finish(); System.exit(0);

                } });
            AlertDialog alert = builder.create();
            alert.show(); // Show Alert Dialog

Thank you so much in advance. and any code snippet will be a great help.