How to save the result of the method when flipping the screen (Android Studio)?

Question

Good day. Faced such a problem (I practice on the Android book. Programming for professionals. 3rd edition - stuck on the last assignments of chapter 5): lower class, which allows the user to peep the correct answer to a simple question. After viewing the tooltip when you go back to the questions and clicking on the correct answer, the user will see the inscription "Cheat is not good." The problem is that in this class you need to save the result - whether the user has spied the answer so that when the phone screen is turned over, this indicator will not be reset. I do not understand how to do this. What exactly should be saved? In place of the code -> (________) I tried to substitute the value of mAnswerIsTrue - but this did not give the expected results. I think that you need to save the result of executing the wasAnswerShown method, but this is only a guess. Thank you in advance)

public class CheatActivity extends AppCompatActivity { //константа TAG (источник сообщения) = "имя класса" public static final String TAG = "CheatActivity"; //ключ для дополнения-интента который CheatActivity читает и использует (в методе newIntent) private static final String EXTRA_ANSWER_IS_TRUE = "com.bignerdranch.android.geoquiz.answer_is_true"; //ключ дополнения для назначения результата private static final String EXTRA_ANSWER_SHOWN = "com.bignerdranch.android.geoquiz.answer_shown"; private boolean mAnswerIsTrue; private TextView mAnswerTextView; private Button mShowAnswerButton; //инкапсулированный метод для включения дополнения в интент //он позволяет создать объект Intent, настроенный дополнениями, необходимыми для CheatActivity // boolean answerIsTrue - выступает значением в дополнении // (включение дополнения в интент - интент.дополнение(ключ,значение)) public static Intent newIntent (Context packageContext, boolean answerIsTrue){ Intent intent = new Intent(packageContext, CheatActivity.class); //далее интент.дополнение (ключ, значение) intent.putExtra(EXTRA_ANSWER_IS_TRUE, answerIsTrue); return intent; } //декодирование интента результата (из метода setAnswerShownResult) public static boolean wasAnswerShown (Intent result){ return result.getBooleanExtra(EXTRA_ANSWER_SHOWN,false); } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Log.d(TAG, "onCreate(Bundle) called");// <- эта строка регистрирует сообщение (Log.d), // ^(источник сообщения,"какое сообщение вывести") setContentView(R.layout.activity_cheat); if (savedInstanceState != null){ ___________ = savedInstanceState.getBoolean(EXTRA_ANSWER_SHOWN, ___________); } // метод для чтения значения из дополнения + сохранение значения в переменной mAnswerIsTrue mAnswerIsTrue = getIntent().getBooleanExtra(EXTRA_ANSWER_IS_TRUE, false); mAnswerTextView = (TextView) findViewById(R.id.answer_text_view); mShowAnswerButton = (Button) findViewById(R.id.show_answer_button); //далее когда нажимаем на "Show Answer" - показать текст правильного ответа 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); } @Override public void onSaveInstanceState(Bundle saveInstanceState) { super.onSaveInstanceState(saveInstanceState); Log.d(TAG, "onSaveInstanceState"); saveInstanceState.putBoolean(EXTRA_ANSWER_SHOWN,__________); }

A. Shakhov A. Shakhov 1,438 3 15 · Accepted Answer · 2018-04-11T07:49:25

1) First you need to declare the variable private boolean mWasAnswerShown

2) In the onCreate method, you need to retrieve the saved value in this way:

 if (savedInstanceState != null) { mWasAnswerShown = savedInstanceState.getBoolean(EXTRA_ANSWER_SHOWN, false); // второй параметр - значение по умолчанию // если в savedInstanceState не окажется объекта с тегом EXTRA_ANSWER_SHOWN }

3) And in the onSaveInstanceState method, save the value of the mWasAnswerShown variable in this way:

 saveInstanceState.putBoolean(EXTRA_ANSWER_SHOWN, mWasAnswerShown);

PS If you run CheatActivity activations from those activations with questions and you need some CheatActivity results, you can also use CheatActivity in your activations with pending results:

 Intent startCheatActivityIntent = new Intent(this, CheatActivity.class); startActivityForResult(startCheatActivityIntent, 1);

In the CheatActivity code, put the required data into the intent:

 Intent resultsIntent = new Intent(); resultsIntent.putExtra(EXTRA_ANSWER_SHOWN, mWasAnswerShown); setResult(RESULT_OK, resultsIntent); finish();

When returning from CheatActivity in the activation code with questions, you will have access to this intent, in which you put the data, in the following method:

 @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (data == null) return; boolean wasAnswerShown = data.getBooleanExtra(CheatActivity.EXTRA_ANSWER_SHOWN); if(wasAnswerShown) Toast.makeText(QuestionsActivity.this, "Читерить нехорошо", Toast.LENGTH_SHORT).show(); }

I ask you, explain a little, the value of the declared variable mWasAnswerShown be through the key EXTRA_ANSWER_SHOWN - right?
Since, for example, in your case, in Intent you can put two values of the type boolean mAnswerIsTrue and mWasAnswerShown , therefore for each variable you need to have such a tag.
Usually they are declared as public static final in any one place
That is, for the variables mentioned, mAnswerIsTrue and mWasAnswerShown must have different keys, otherwise there will be conflicts, and if I specify the key of the necessary variable in the onSaveInstanceState method, then its value will be saved - right?
@ AlekseyEfimov, yes, there is a key for each object, since everything is stored in the Bundle as key-value pairs.
Accordingly, under what key you save, under this and should be pulled back

Aidar Zainutdinov Aidar Zainutdinov 126 9 · Answer 2 · 2018-04-11T07:14:35

When you rotate the screen, the onCreate method is called again. It seems to me that you can override the onStop or onPause methods and save states in them. And in the onCreate method, see if the saved state is empty and, if not, pull it out.

How to save the result of the method when flipping the screen (Android Studio)?

2 answers 2

More articles: