Android Xử lý lưu điểm với SharedPreferences và xếp hạng

Xem giúp mình đoạn code này với, ko chạy được.

package duaxe.canhquy.pecc4.duaxe;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;

public class Main4Activity extends Activity {

    TextView txtvScore;
    TextView txtvName4;
    Button btnRetry;
    Button btnBackMenu;
    String name, ten, ngay;
    Integer score;
    Integer i, j, diem;
    String[] mangNgay;
    String[] mangTen;
    Integer[] mangDiem;
    SharedPreferences luutru;

   
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main4);
        txtvScore = (TextView) findViewById(R.id.textViewScore4);
        btnRetry = (Button) findViewById(R.id.buttonTryagain);
        btnBackMenu = (Button)findViewById(R.id.buttonBackMenu);
        txtvName4 = (TextView) findViewById(R.id.textViewName4);
       
        luutru = getSharedPreferences("luutruthongtin", Context.MODE_PRIVATE);
        xulyluudiem();
    }

    private void xulyluudiem() {
        Bundle bd4 = getIntent().getExtras();
        if (bd4 != null) {
            name = bd4.getString("name");
            score = bd4.getInt("score");
            txtvScore.setText("Score: " + score);
            txtvName4.setText(name);
        }
        if(luutru == null) {
            mangNgay = new String[]{"-", "-", "-", "-", "-", "-", "-", "-", "-"};
            mangTen = new String[]{"-", "-", "-", "-", "-", "-", "-", "-", "-"};
            mangDiem = new Integer[]{0, 0, 0, 0, 0, 0, 0, 0, 0};
        }else {
            String ten1 = luutru.getString("ten1", "");
            String ten2 = luutru.getString("ten2", "");
            String ten3 = luutru.getString("ten3", "");
            String ten4 = luutru.getString("ten4", "");
            String ten5 = luutru.getString("ten5", "");
            String ten6 = luutru.getString("ten6", "");
            String ten7 = luutru.getString("ten7", "");
            String ten8 = luutru.getString("ten8", "");

            String ngay1 = luutru.getString("ngay1", "");
            String ngay2 = luutru.getString("ngay2", "");
            String ngay3 = luutru.getString("ngay3", "");
            String ngay4 = luutru.getString("ngay4", "");
            String ngay5 = luutru.getString("ngay5", "");
            String ngay6 = luutru.getString("ngay6", "");
            String ngay7 = luutru.getString("ngay7", "");
            String ngay8 = luutru.getString("ngay8", "");

            String diem1 = luutru.getString("diem1", "");
            String diem2 = luutru.getString("diem2", "");
            String diem3 = luutru.getString("diem3", "");
            String diem4 = luutru.getString("diem4", "");
            String diem5 = luutru.getString("diem5", "");
            String diem6 = luutru.getString("diem6", "");
            String diem7 = luutru.getString("diem7", "");
            String diem8 = luutru.getString("diem8", "");

            mangNgay = new String[]{ten1, ten2, ten3, ten4, ten5, ten6, ten7, ten8,"-"};
            mangTen = new String[]{ngay1, ngay2, ngay3, ngay4, ngay5, ngay6, ngay7, ngay8, "-"};
            mangDiem = new Integer[]{Integer.parseInt(diem1),Integer.parseInt(diem2),
                    Integer.parseInt(diem3),Integer.parseInt(diem4),
                    Integer.parseInt(diem5),Integer.parseInt(diem6),
                    Integer.parseInt(diem7),Integer.parseInt(diem8),  5};
        }

        mangDiem[9] = score;
        mangTen[9] = name;
        for (i = 0; i <= 5; i++) {
            for (j = i + 1; j <= 5; j++) {
                if (mangDiem[i] < mangDiem[j]) {
                    diem = mangDiem[i];
                    mangDiem[i]=mangDiem[j];
                    mangDiem[j]=diem;
                    ten = mangTen[i];
                    mangTen[i] = mangTen[j];
                    mangTen[j] = ten;
                }
            }

        }

        SharedPreferences.Editor edit = luutru.edit();
        if(luutru!=null){
            edit.clear();
        }else {
            edit.putString("ten1", String.valueOf(mangTen[0]));
            edit.putString("ten2", String.valueOf(mangTen[1]));
            edit.putString("ten3", String.valueOf(mangTen[2]));
            edit.putString("ten4", String.valueOf(mangTen[3]));
            edit.putString("ten5", String.valueOf(mangTen[4]));
            edit.putString("ten6", String.valueOf(mangTen[5]));
            edit.putString("ten7", String.valueOf(mangTen[6]));
            edit.putString("ten8", String.valueOf(mangTen[7]));
            edit.putString("ten9", String.valueOf(mangTen[8]));

            edit.putString("ngay1", String.valueOf(mangNgay[0]));
            edit.putString("ngay2", String.valueOf(mangNgay[1]));
            edit.putString("ngay3", String.valueOf(mangNgay[2]));
            edit.putString("ngay4", String.valueOf(mangNgay[3]));
            edit.putString("ngay5", String.valueOf(mangNgay[4]));
            edit.putString("ngay6", String.valueOf(mangNgay[5]));
            edit.putString("ngay7", String.valueOf(mangNgay[6]));
            edit.putString("ngay8", String.valueOf(mangNgay[7]));
            edit.putString("ngay9", String.valueOf(mangNgay[8]));

            edit.putString("diem1", String.valueOf(mangDiem[0]));
            edit.putString("diem2", String.valueOf(mangDiem[1]));
            edit.putString("diem3", String.valueOf(mangDiem[2]));
            edit.putString("diem4", String.valueOf(mangDiem[3]));
            edit.putString("diem5", String.valueOf(mangDiem[4]));
            edit.putString("diem6", String.valueOf(mangDiem[5]));
            edit.putString("diem7", String.valueOf(mangDiem[6]));
            edit.putString("diem8", String.valueOf(mangDiem[7]));
            edit.commit();
        }
    }
}