Why function call of setAnswerShownResult(true) becomes "error: invalid method declaration; return type required"?

Android Programming (3rd Edition) 5. Your Second Activity
1

Hi there,

In the following code of 3rd version of chap.5 - CheatActivity.java, Android Studio marks line setAnswerShownResult(true) - “error: invalid method declaration; return type required,missing method body…” and says function definition private void setAnswerShownResult(boolean isAnswerShown) is never used. What’s wrong here. Please see the more detail of these errors from the attached screen shoot.

Android1
Android11920×1200 275 KB

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_cheat);
    mAnswerIsTrue = getIntent().getBooleanExtra(EXTRA_ANSWER_IS_TRUE, false);
    mAnswerTextView = (TextView) findViewById(R.id.answer_text_view);

    mShowAnswerButton = (Button) findViewById(R.id.show_answer_button);
    mShowAnswerButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (mAnswerIsTrue) {
                mAnswerTextView.setText(R.string.true_button);
            } else {
                mAnswerTextView.setText(R.string.false_button);
            }
        }

        setAnswerShownResult(true);
    });
}

private void setAnswerShownResult(boolean isAnswerShown){
        Intent data = new Intent();
        data.putExtra(EXTRA_ANSWER_SHOWN, isAnswerShown);
        setResult(RESULT_OK, data);
}