Question

public class CheatActivity extends AppCompatActivity {


private static final String EXTRA_ANSWER_IS_TRUE="com.example.ferhat.geoquiz.answer_is_true";
public static final String EXTRA_ANSWER_SHOWN="com.example.ferhat.geoquiz.answer_shown";
private static final String CHEATER="com.example.ferhat.geoquiz.cheated";
private Boolean mAnswerIsTrue;
private TextView mAnswerTextView;
private Button mShowAnswer;
private Boolean mIsCheater;
public static Intent newIntent(Context packageContext, boolean answerIsTrue){
    Intent i=new Intent(packageContext,CheatActivity.class);
    i.putExtra(EXTRA_ANSWER_IS_TRUE,answerIsTrue);
    return i;
}
@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.answerTextView);

    mShowAnswer = (Button) findViewById(R.id.showAnswerButton);
    mShowAnswer.setOnClickListener(new View.OnClickListener() {

        //Cevabı gösteriyor ve Kopya çekildi bilgisi veriliyor
        @Override
        public void onClick(View v) {
            if (mAnswerIsTrue) {
                mAnswerTextView.setText(R.string.true_button);
            } else {
                mAnswerTextView.setText(R.string.false_button);
            }
            mIsCheater=true;
            setAnswerShownResult();
        }
    });

     if(savedInstanceState!=null){
        mIsCheater=savedInstanceState.getBoolean(CHEATER,false);
    }

}

    private void setAnswerShownResult(){
    Intent data=new Intent();
    data.putExtra(EXTRA_ANSWER_SHOWN,mIsCheater);
    setResult(RESULT_OK,data);
}
@Override
public void onSaveInstanceState(Bundle savedInstanceState){
    super.onSaveInstanceState(savedInstanceState);
    savedInstanceState.putBoolean(CHEATER,mIsCheater);
}
}

我尝试在Anroid Programming，Big Nerds Ranch Guide（第5章）中解决挑战挑战要求我在屏幕旋转和问题之间的交易时保留作弊数据。主要活动存在问题，CheatActivity有主要活动的答案。我创建了BooleanArray来保存问题的作弊数据。

问题是，我为第一个问题作弊，然后当我在其他问题的CheatActivity（CheatPage）中时，如果我旋转屏幕，程序会崩溃。

此行导致的错误 savedInstanceState.putBoolean（CHEATER，mIsCheater）; 我想我需要清除先前作弊数据中的数据（BooleanArray已经持有它），但我不知道该怎么做。

Answer 1

public class CheatActivity extends AppCompatActivity {


private static final String EXTRA_ANSWER_IS_TRUE = "com.example.ferhat.geoquiz.answer_is_true";
public static final String EXTRA_ANSWER_SHOWN = "com.example.ferhat.geoquiz.answer_shown";
public static final String EXTRA_CHEATED = "com.example.ferhat.geoquiz.cheated";
private static final String CHEATER = "com.example.ferhat.geoquiz.cheated";
private Boolean mAnswerIsTrue;
private TextView mAnswerTextView;
private Button mShowAnswer;
private Boolean mAnswerEverShown;
private Boolean twoStep=false;


//Yeni intent methodu yarattık Cevabı alıyor ve bu activity i başlatıyor
public static Intent newIntent(Context packageContext, boolean answerIsTrue, boolean checked) {
    Intent i = new Intent(packageContext, CheatActivity.class);
    i.putExtra(EXTRA_ANSWER_IS_TRUE, answerIsTrue);
    i.putExtra(EXTRA_CHEATED, checked);
    return i;
}



private void setAnswerShownResult(Boolean isAnswerShown) {
    Intent data = new Intent();
    **if(mAnswerEverShown) {
        isAnswerShown=mAnswerEverShown;
        data.putExtra(EXTRA_ANSWER_SHOWN, isAnswerShown);
        setResult(RESULT_OK, data);
    }else {
        data.putExtra(EXTRA_ANSWER_SHOWN, isAnswerShown);
        setResult(RESULT_OK, data);
    }
    twoStep=isAnswerShown;**

}

@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.answerTextView);
    **mAnswerEverShown = getIntent().getBooleanExtra(EXTRA_CHEATED, false);**
    mShowAnswer = (Button) findViewById(R.id.showAnswerButton);
    mShowAnswer.setOnClickListener(new View.OnClickListener() {

        //Cevabı gösteriyor ve Kopya çekildi bilgisi veriliyor
        @Override
        public void onClick(View v) {
            if (mAnswerIsTrue) {
                mAnswerTextView.setText(R.string.true_button);
            } else {
                mAnswerTextView.setText(R.string.false_button);
            }
            twoStep=true;
            setAnswerShownResult(twoStep);
        }

    });

    **if (savedInstanceState != null) {
        setAnswerShownResult(savedInstanceState.getBoolean(CHEATER, false));
    }
}
    @Override
    public void onSaveInstanceState (Bundle savedInstanceState){
        super.onSaveInstanceState(savedInstanceState);
        savedInstanceState.putBoolean(CHEATER, twoStep);
    }
}**

我找到了适合各种情况的解决方案。首先想到我做了;我从主要活动中获取信息

mAnswerEverShown = getIntent().getBooleanExtra(EXTRA_CHEATED, false);

然后我改变setAnswerShownResult两种情况。如果没有被欺骗，程序会发送当前数据（被欺骗与否）。我用*标记了我改变的地方。

Answer 2

在回调超级方法之前，您需要putBoolean。

@Override
public void onSaveInstanceState(Bundle savedInstanceState){
  savedInstanceState.putBoolean(CHEATER,mIsCheater);
  super.onSaveInstanceState(savedInstanceState);
}

如果没有，则不会保存CHEATER，并且在resume活动

时无法调用它

savedInstanceState导致屏幕旋转时崩溃

2 个答案: