getBooleanExtra() using only the default argument

Question

Here's the code. In this part, the answerIsTrue variable should be initialized to true, which it rightly does (I debugged and checked) and is rightly also passed into putExtra() (again, I debugged and checked).

mCheatButton.setOnClickListener(new View.OnClickListener(){
        public void onClick(View v){
            Intent i = new Intent(QuizActivity.this, CheatActivity.class);
            boolean answerIsTrue = mQuestionBank[mCurrentIndex].isTrueQuestion();
            i.putExtra(CheatActivity.EXTRA_ANSWER_IS_TRUE, answerIsTrue);
            startActivity(i);
        }
    });

But coming to a different class, the variable mAnswerIsTrue gets assigned to false (probably due to the default argument) despite the argument being passed by putExtra() is true. Here's the code.

mAnswerIsTrue = getIntent().getBooleanExtra(EXTRA_ANSWER_IS_TRUE, false);

I debugged this line as well, and it does get assigned to false. What could be wrong?

Here's the complete CheatActivity class:

public class CheatActivity extends Activity {
public static final String EXTRA_ANSWER_IS_TRUE = "com.bignerdranch.android.geoquiz.answer_is_true";
private Button mShowAnswerButton;
private boolean mAnswerIsTrue;
private TextView mAnswerTextView;
@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_cheat);
    mAnswerIsTrue = getIntent().getBooleanExtra(CheatActivity.EXTRA_ANSWER_IS_TRUE, false);
    mAnswerTextView = (TextView)findViewById(R.id.answerTextView);
    mShowAnswerButton = (Button)findViewById(R.id.showAnswerButton);
    mShowAnswerButton.setOnClickListener(new View.OnClickListener(){
        public void onClick(View v){
            if (mAnswerIsTrue){
                mAnswerTextView.setText(R.id.true_button);
            }else{
                mAnswerTextView.setText(R.id.false_button);
            }
        }
    });
}

}

Note: I'm a complete beginner, who just learnt debugging.

Answer 1

Every time you rotate your screen, you should call pullExtra method. I am learning Android as well, but it seems to me that everytime onCreate method is called, Android app forgets all information about intend.

My code for that parts looks like this:

protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_cheat);


        mAnswerIsTrue = getIntent().getBooleanExtra(EXTRA_ANSWER_IS_TRUE, true );

        if(savedInstanceState != null ){

            mShownAnswer = savedInstanceState.getBoolean(KEY_IS_CHEATER, false);
            setAnswerShownResult(mShownAnswer);

            Log.i(TAG, String.format("IsACheater: %b", mShownAnswer) );
        }
        else{
            setAnswerShownResult(false);
        }

...

Answer 2

Use instead of .getBooleanExtra() the intent.extras.get(). So your code will same like this:

val mAnswerIsTrue = ((intent.extras.get("EXTRA_ANSWER_IS_TRUE")).toString()).toBoolean()

You need to cast, if you want to use the variable as an boolean.

If you want to put more extra, you need make a Bundle:

val extras = Bundle()
extras.putString("KEY_string", someString)
extras.putBoolean("KEY_boolean", someBoolean)

var intent = Intent(context,StartingActivity::class.java)
intent.putExtras(extras)

Answer 3

In your CheatActivity initialize mAnswerIsTrue in onCreate() like this:

private boolean mAnswerIsTrue = false; // default value

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mAnswerIsTrue = getIntent().getBooleanExtra(EXTRA_ANSWER_IS_TRUE, false);
}

Answer 4

for getting the data use the code

Boolean answertrue =getIntent().getExtras().getBoolean(CheatActivity.EXTRA_ANSWER_IS_TRUE);

in button click use the code

Intent i = new Intent(QuizActivity.this, CheatActivity.class);
 boolean answerIsTrue = true; 
i.putExtra(CheatActivity.EXTRA_ANSWER_IS_TRUE, answerIsTrue); 
startActivity(i);

Answer 5

" Ctrl + B " to get in method in API. (android studio)

public boolean getBooleanExtra(String name, boolean defaultValue) {

        return mExtras == null ? defaultValue :
            mExtras.getBoolean(name, defaultValue);

    }

defaultValue the value to be returned if no value of the desired type is stored with the given name.

Answer 6

I cannot be sure, but my best guess that, getBooleanExtra() is not good. I suggest using simple getExtras and then getting your value.

 i.putExtra(EXTRA_ANSWER_IS_TRUE, value);

 Bundle args = MyActivity.getIntent().getExtras();
 boolean istrue= args.getBoolean(EXTRA_ANSWER_IS_TRUE, false);