Android ArrayList Verileri Kaydetme

selamlar 

Şu kodda nasıl son sorulan soruya dönebilirim uygulma kapatılıp açıldığında

arraylisti gson ile kaydetmeye çalıştım ama olmuyor buton eklemek de hata veriyor

yardımlarınız için Hepinize şimididen Teşekkürler

import android.content.DialogInterface;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.Random;

public class MainActivity extends AppCompatActivity {

    private TextView countLabel;
    private ImageView questionImage;
    private EditText editText;

    private String rightAnswer;
    private int rightAnswerCount = 0;
    private int quizCount = 1;

    ArrayList<ArrayList<String>> quizArray = new ArrayList<>();

    String quizData[][] = {
            // {"Image Name", "Right Answer"}
            {"image_circle", "circle"},
            {"image_triangle", "triangle"},
            {"image_square", "square"},
            {"image_pentagon", "pentagon"},
            {"image_hexagon", "hexagon"},
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        countLabel = findViewById(R.id.countLabel);
        questionImage = findViewById(R.id.questionImage);
        editText = findViewById(R.id.editText);

        editText.setOnKeyListener(new View.OnKeyListener() {
            @Override
            public boolean onKey(View view, int keyCode, KeyEvent keyEvent) {

                if (keyEvent.getAction() == KeyEvent.ACTION_DOWN) {

                    if (keyCode == KeyEvent.KEYCODE_ENTER) {
                        checkAnswer();
                    }

                }

                return false;
            }
        });

        // Create quizArray from quizData.
        for (int i = 0; i < quizData.length; i++) {

            // Prepare array.
            ArrayList<String> tmpArray = new ArrayList<>();
            tmpArray.add(quizData[i][0]); // Image Name
            tmpArray.add(quizData[i][1]); // Right Answer

            // Add tmpArray to quizArray.
            quizArray.add(tmpArray);

        }

        showNextQuiz();
    }

    public void showNextQuiz() {

        // Update quizCountLabel.
        countLabel.setText("Q" + quizCount);

        // Generate random number between 0 and 4 (quizArray's size -1)
        Random random = new Random();
        int randomNum = random.nextInt(quizArray.size());

        // Pick one quiz set.
        ArrayList<String> quiz = quizArray.get(randomNum);

        // Set image and right answer.
        // Array format: {"Image Name", "Right Answer"}
        questionImage.setImageResource(
                getResources().getIdentifier(quiz.get(0), "drawable", getPackageName()));
        rightAnswer = quiz.get(1);

        // Remove this quiz from quizArray.
        quizArray.remove(randomNum);
    }


    public void checkAnswer() {

        // Get editText.
        String answer = editText.getText().toString().toLowerCase();

        String alertTitle;

        if (answer.equals(rightAnswer)) {
            // Correct!
            alertTitle = "Correct!";
            rightAnswerCount++;
        } else {
            // Wrong...
            alertTitle = "Wrong...";
        }

        // Create Dialog.
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle(alertTitle);
        builder.setMessage("Answer : " + rightAnswer);
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {

                editText.setText("");

                if (quizArray.size() < 1) {
                    // quizArray is empty.
                    showResult();

                } else {
                    quizCount++;
                    showNextQuiz();
                }

            }
        });
        builder.setCancelable(false);
        builder.show();
    }

    public void showResult() {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Result");
        builder.setMessage(rightAnswerCount + " / 5");
        builder.setPositiveButton("Try Again", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                recreate();
            }
        });
        builder.setNegativeButton("Quit", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                finish();
            }
        });
        builder.show();
    }
}