Challenge 2 App Crashes

Android Programming (3rd Edition) 3. The Activity Lifecycle
1

I am trying to see if the user is on the last question and if so display a toast saying the percentage correct if any.

Here is my code for the project.

package com.bignerdranch.android.geoquizuse;

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.ImageButton;
import android.widget.TextView;
import android.widget.Toast;

public class QuizActivity extends AppCompatActivity {

private Button TrueButton;
private Button FalseButton;
private ImageButton PreviousButton;
private ImageButton NextButton;
private TextView QuestionTextView;
private final static String TAG = "QuizActivity";
private final static String KEY_INDEX = "index";
private int Percentage = 0;


private Question[] QuestionBank = 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)
};

public static<T> boolean getIndex(T[] a, T target) {
    for (int i = 0; i < a.length; i++)
        if (target.equals(a[i]))
            return true;
    return false;
}

private boolean[] QuestionsAnswered = new boolean[QuestionBank.length];

private int CurrentIndex = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Log.d(TAG, "onCreate calldd");
    setContentView(R.layout.activity_quiz);

    if (savedInstanceState != null) {
        CurrentIndex = savedInstanceState.getInt(KEY_INDEX, 0);
        QuestionsAnswered = savedInstanceState.getBooleanArray(KEY_INDEX);

    }

    QuestionTextView = findViewById(R.id.question_text_view);
    QuestionTextView.setOnClickListener(new View.OnClickListener() {
       @Override
       public void onClick(View v) {
           CurrentIndex = (CurrentIndex + 1) % QuestionBank.length;
           updateQuestion();
       }
    });

    TrueButton = findViewById(R.id.true_button);
    TrueButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            checkAnswer(true);
        }
    });
    FalseButton = findViewById(R.id.false_button);
    FalseButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            checkAnswer(false);
        }
    });

    PreviousButton = findViewById(R.id.prev_button);
    PreviousButton.setOnClickListener(new View.OnClickListener() {
       @Override
        public void onClick(View v) {
           CurrentIndex = (CurrentIndex + QuestionBank.length - 1) % QuestionBank.length;
           updateQuestion();
       }
    });

    NextButton = findViewById(R.id.next_button);
    NextButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            CurrentIndex = (CurrentIndex + 1) % QuestionBank.length;
            updateQuestion();
        }
    });
    updateQuestion();
}

@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, CurrentIndex);
    savedInstanceState.putBooleanArray(KEY_INDEX, QuestionsAnswered);
    savedInstanceState.putInt(KEY_INDEX, CurrentIndex);
}

@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 = QuestionBank[CurrentIndex].getTextResId();
    QuestionTextView.setText(question);
    TrueButton.setEnabled(!QuestionsAnswered[CurrentIndex]);
    FalseButton.setEnabled(!QuestionsAnswered[CurrentIndex]);
}

private void checkAnswer(boolean userPressedTrue) {
    int PercentCorrect = 0;
    boolean answerIsTrue = QuestionBank[CurrentIndex].isAnswerTrue();

    int messageResId = 0;

    if (userPressedTrue == answerIsTrue) {
        messageResId = R.string.correct_toast;
        Percentage++;
    } else {
        messageResId = R.string.incorrect_toast;
    }

    Toast.makeText(this, messageResId, Toast.LENGTH_SHORT).show();

    QuestionsAnswered[CurrentIndex] = true;
    TrueButton.setEnabled(false);
    FalseButton.setEnabled(false);

    if (getIndex(QuestionBank, QuestionBank[QuestionBank.length - 1])) { //causes app to crash
        PercentCorrect = Percentage/QuestionBank.length;
        String Correct = "Percent correct: " + PercentCorrect;

        Toast.makeText(this, Correct, Toast.LENGTH_SHORT).show();

        Percentage = 0;
    }
}

}

Why is the app crashing and how to stop this?

2

Please paste the crash log for further analyzation.

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