Android Studio:

Add a counter to the Question class to track the number of times a question was answered correctly / incorrectly.

QuizActivity.java import android.os.Bundle; import android.support.v7.app.AppCompatActivity; 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 Button mTrueButton, mFalseButton, mNextButton; private TextView mQuestionTextView; private TextView mScoreTextView; private String scoreMessage; private int correctCounter; private int incorrectCounter; private static final String TAG = "QuizActivity"; private static final String KEY_INDEX = "index"; 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; @Override protected void onCreate(Bundle savedInstanceState) { Log.d(TAG, "The onCreate() event was run."); super.onCreate(savedInstanceState); setContentView(R.layout.activity_quiz); mScoreTextView = (TextView) findViewById(R.id.score_text_view); if (savedInstanceState != null) { mCurrentIndex = savedInstanceState.getInt(KEY_INDEX, 0); correctCounter=savedInstanceState.getInt("correctCounter"); incorrectCounter=savedInstanceState.getInt("incorrectCounter"); mScoreTextView.setText(scoreMessage); } else { correctCounter = 0; incorrectCounter = 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; updateQuestion(); } }); updateQuestion(); } 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 (userPressedTrue == answerIsTrue) { messageResId = R.string.correct_toast; correctCounter++; } else { messageResId = R.string.incorrect_toast; incorrectCounter++; } Toast.makeText(this, messageResId, Toast.LENGTH_SHORT) .show(); scoreMessage = "Correct: " + correctCounter + " Incorrect: " + incorrectCounter; mScoreTextView.setText(scoreMessage); } @Override public void onSaveInstanceState(Bundle savedInstanceState) { super.onSaveInstanceState(savedInstanceState); Log.i(TAG, "onSaveInstanceState"); savedInstanceState.putInt(KEY_INDEX, mCurrentIndex); } /** Called when the activity is about to become visible. */ @Override protected void onStart() { super.onStart(); Log.d(TAG, "The onStart() event was run."); } /** Called when the activity has become visible. */ @Override protected void onResume() { super.onResume(); Log.d(TAG, "The onResume() event was run."); } /** Called when another activity is taking focus. */ @Override protected void onPause() { super.onPause(); Log.d(TAG, "The onPause() event was run."); } /** Called when the activity is no longer visible. */ @Override protected void onStop() { super.onStop(); Log.d(TAG, "The onStop() event was run."); } /** Called just before the activity is destroyed. */ @Override protected void onDestroy() { super.onDestroy(); Log.d(TAG, "The onDestroy() event was run."); } } 

public class Question private int mTextResId; private boolean mAnswerTrue; public int getTextResId return mTextResId; public void setTextRestd (int textResId) mTextResid = textRes1d; public boolean isAnswerTrue) return mAnswerTrue; public void setAuswertrue (boolean answerTrue)t answe rTrue ; mAnswerTrue ublic Question (int textResId, boolean answerTrue)t mTextResId -textResId; mAnswerTrueanswerTrue