public class DBHelperForSearched extends SQLiteOpenHelper {

public static final String DATABASE_NAME = "searched";
public static final String TABLE_NAME = "searched_table";
public static final String COL1 = "ID";
public static final String COL2 = "ITEM1";
public static final String COL3 = "ITEM2";


DBAdapterForSearched dbAdapter;
Cursor cursor;
ListView list;

public DBHelperForSearched(Context context) {
    super(context, DATABASE_NAME, null, 1);
}

@Override
public void onCreate(SQLiteDatabase db) {
    String createTable = "CREATE TABLE " + TABLE_NAME + "(ITEM1 TEXT primary key," + " ITEM2 TEXT)";
    db.execSQL(createTable);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP IF TABLE EXISTS " + TABLE_NAME);
    onCreate(db);
}

public boolean insertDataToSearched(String item1, String item2) {
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues contentValues = new ContentValues();
    contentValues.put(COL2, item1);
    contentValues.put(COL3, item2);

    long result = db.insert(TABLE_NAME, null, contentValues);

    if (result == -1) {
        return false;
    } else {
        return true;
    }
}

public Cursor getListContents(){
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor data = db.rawQuery("SELECT * FROM " + TABLE_NAME, null);
    return data;
}

}

db헬퍼 코드입니다. 한 영역을 primary key로 정해 db에 중복된 primary key값 없이 저장하는 액티비티를 만들고 있는데, 어째서인지 해당 액티비티의 실행이 계속 중지가 됩니다. 무엇이 문제인지를 잘 모르겠습니다. 조언 부탁드립니다.

아래로는 위 db를 활용하는 액티비티입니다.

--------------------------------------------------조언해주신대로 수정했습니다-----------------------------------------------

public class Searched extends AppCompatActivity {

static String DATABASE_NAME;
static String TABLE_NAME;
static int DATABASE_VERSION;
private static final String TAG = "TestDataBaseActivity";
private DBHelperForSearched db;
ListView list;
public String data_city, data_country;


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


    db = new DBHelperForSearched(this);


    list = (ListView) findViewById(R.id.searched_list);
    db.getListContents();

    final ArrayList<InfoClassForSearched> weatherList = new ArrayList<InfoClassForSearched>();
    Cursor data = db.getListContents();

    if (data.getCount() == 0) {
        Toast.makeText(this, "There are no contents in this list!", Toast.LENGTH_LONG).show();
    } else {
        while (data.moveToNext()) {
            InfoClassForSearched newInfo = new InfoClassForSearched(data.getString(0), data.getString(1));
            weatherList.add(newInfo);
            DBAdapterForSearched dbAdapter = new DBAdapterForSearched(this, weatherList);
            list.setAdapter(dbAdapter);
        }
    }


    list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

            InfoClassForSearched selectedInfoClass = weatherList.get(position);
            data_city = selectedInfoClass.getCity();
            data_country = selectedInfoClass.getCountry();

            Intent intent = new Intent(Searched.this, MainActivity.class);

            intent.putExtra("data_city", data_city);
            intent.putExtra("data_country", data_country);


            setResult(Activity.RESULT_OK, intent);
            finish();

        }
    });
}

}