Guessing game - comparing input number to computers generated number

I'm trying to develop an app that compares the user's input number to a randomly generated number from the computer, depending on whether the input number is higher, lower or the same as the generated number, there is a different message output. However the app crashes whenever I try and run it. Here is my code for my method:

If anyone can recognise why it's crashing it would be great - new to Android so it's hard to see errors.

public void guessingGame (View v)
{
    EditText guess = (EditText) findViewById(R.id.ETguess);
    TextView guessError = (TextView) findViewById(R.id.guessError);
    TextView compGuess = (TextView) findViewById(R.id.tvCompGuess);

    int guessValue = Integer.parseInt(guess.getText().toString());

    if (guessValue > 20)
    {
        guessError.setVisibility(View.VISIBLE);
        guess.getText().clear();
    }
    else if (guessValue < 1)
    {
        guessError.setVisibility(View.VISIBLE);
        guess.getText().clear();
    }
    else 
    {
        int min = 1;
        int max = 20;

        Random r = new Random();
        int i = r.nextInt(max - min + 1) + min;

        int computerNumber = i;
        compGuess.setText(i);

        if (computerNumber > guessValue)
        {
            guessError.setText("Too low!");
        }
        else if (computerNumber < guessValue)
        {
            guessError.setText("Too high!");
        }
        else if (computerNumber == guessValue)
        {
            guessError.setText("Good Guess!");
        }
    }

}