关于《Android编程权威指南》第5.5挑战练习的困惑

[wokaoyan1981]

已知漏洞：用户作弊后，可以旋转CheatActivity来清除作弊痕迹。
我的思路：在旋转前通过覆盖onSAveinstanceState方法保存信息，旋转后，在onCreate方法内恢复信息。
困惑：CheatActivity需要保存哪些信息？具体如何实现？请最小化修改。
两个Activity代码如下，（xml文件略）

package com.bignerdranch.android.geoquiz;

import android.app.Activity;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class QuizActivity extends AppCompatActivity {

    private static final String TAG = "QuizActivity";
    private static final String KEY_INDEX = "index";
    private static final int REQUEST_CODE_CHEAT = 0;
    private Button mTrueButton;
    private Button mFalseButton;
    private Button mNextButton;
    private Button mCheatButton;
    private TextView mQuestionTextView;

    private Question[] mQuestionBank = new Question[]{
            new Question(R.string.question_australia, true),
            new Question(R.string.question_oceans, true),
            new Question(R.string.question_mideast, false),
            new Question(R.string.question_africa, false),
            new Question(R.string.question_americas, true),
            new Question(R.string.question_asia, true)
    };

    private int mCurrentIndex = 0;
    private boolean mIsCheater;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d(TAG, "onCreate(Bundle) called");
        setContentView(R.layout.activity_quiz);

        if (savedInstanceState != null) {
            mCurrentIndex = savedInstanceState.getInt(KEY_INDEX, 0);
        }

        mQuestionTextView = (TextView) findViewById(R.id.question_text_view);


        mTrueButton = (Button) findViewById(R.id.true_button);

        mTrueButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                checkAnswer(true);
            }
        });

        mFalseButton = (Button) findViewById(R.id.false_button);
        mFalseButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                checkAnswer(false);
            }
        });

        mNextButton = (Button) findViewById(R.id.next_button);
        mNextButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mCurrentIndex = (mCurrentIndex + 1) % mQuestionBank.length;
                mIsCheater = false;
                updateQuestion();
            }
        });

        mCheatButton = (Button) findViewById(R.id.cheat_button);
        mCheatButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //Start CheatActivity
                boolean answerIsTrue = mQuestionBank[mCurrentIndex].isAnswerTrue();
                Intent intent = CheatActivity.newIntent(QuizActivity.this, answerIsTrue);
                startActivityForResult(intent, REQUEST_CODE_CHEAT);
            }
        });
        updateQuestion();
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode != Activity.RESULT_OK) {
            return;
        }

        if (requestCode == REQUEST_CODE_CHEAT) {
            if (data == null) {
                return;
            }
            mIsCheater = CheatActivity.wasAnswerShown(data);
        }
    }

    @Override
    public void onStart() {
        super.onStart();
        Log.d(TAG, "onStart() called");
    }

    @Override
    public void onResume() {
        super.onResume();
        Log.d(TAG, "onResume() called");
    }

    @Override
    public void onPause() {
        super.onPause();
        Log.d(TAG, "onPause() called");
    }

    @Override
    public void onSaveInstanceState(Bundle savedInstanceState) {
        super.onSaveInstanceState(savedInstanceState);
        Log.i(TAG, "onSaveInstanceState");
        savedInstanceState.putInt(KEY_INDEX, mCurrentIndex);
    }

    @Override
    public void onStop() {
        super.onStop();
        Log.d(TAG, "onStop() called");
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.d(TAG, "onDestroy() called");
    }

    private void updateQuestion() {

        int question = mQuestionBank[mCurrentIndex].getTextResId();
        mQuestionTextView.setText(question);
    }

    private void checkAnswer(boolean userPressedTrue) {
        boolean answerIsTrue = mQuestionBank[mCurrentIndex].isAnswerTrue();

        int messageResId = 0;

        if (mIsCheater) {
            messageResId = R.string.judgment_toast;
        } else {
            if (userPressedTrue == answerIsTrue) {
                messageResId = R.string.correct_toast;
            } else {
                messageResId = R.string.incorrect_toast;
            }
        }

        Toast.makeText(this, messageResId, Toast.LENGTH_LONG)
                .show();
    }
}

package com.bignerdranch.android.geoquiz;

import android.content.Context;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class CheatActivity extends AppCompatActivity {
    private static final String EXTRA_ANSWER_IS_TRUE =
            "com.bignerdranch.android.geoquiz.answer_is_true";
    private static final String EXTRA_ANSWER_SHOWN=
            "com.bignerdranch.android.geoquiz.answer_shown";
    private boolean mAnswerIsTrue;
    private TextView mAnswerTextView;
    private Button mShowAnswerButton;
    
    public static Intent newIntent(Context packageContext, boolean answerIsTrue) {
        Intent intent = new Intent(packageContext, CheatActivity.class);
        intent.putExtra(EXTRA_ANSWER_IS_TRUE, answerIsTrue);
        return intent;
    }

    public static boolean wasAnswerShown(Intent result){
        return result.getBooleanExtra(EXTRA_ANSWER_SHOWN,false);
    }

    @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);
    }
}