关于《Android编程权威指南》5.5挑战练习的困惑

wokaoyan1981 2017-11-12 11:11:41
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: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;
/*;
private boolean mAnswerIsTrue;
*/

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);
}
}

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