基于Android SQLiteOpenHelper && CRUD 的使用

public class OtherPersonService { private DBOpenHelper dbOpenHelper; public OtherPersonService(Context context) {  super();  this.dbOpenHelper = new DBOpenHelper(context, 2); } public void save(Person person) {  SQLiteDatabase db = dbOpenHelper.getWritableDatabase();  ContentValues values = new ContentValues();// ContentValues 专门用于保存字段的值  values.put("name", person.getName());  values.put("phone", person.getPhone());  db.insert("person", null, values);// 第三个参数为字段值,第二个参数为空值字段，如果第三个参数为null } public void delete(Integer id) {  SQLiteDatabase db = dbOpenHelper.getWritableDatabase();  db.delete("person", "personid=?", new String[] { id.toString() }); } public void update(Person person) {  SQLiteDatabase db = dbOpenHelper.getWritableDatabase();  ContentValues values = new ContentValues();  values.put("name", person.getName());  values.put("phone", person.getPhone());  db.update("person", values, "personid=?", new String[] { person.getId().toString() }); } public Person find(Integer id) {  SQLiteDatabase db = dbOpenHelper.getReadableDatabase();  Cursor cursor = db.query("person", null, "personid=?",new String[] { id.toString() }, null, null, null);  if (cursor.moveToFirst()) {   int personid = cursor.getInt(cursor.getColumnIndex("personid"));   String name = cursor.getString(cursor.getColumnIndex("name"));   String phone = cursor.getString(cursor.getColumnIndex("phone"));   return new Person(personid, name, phone);  }  cursor.close();  return null; } /*  * 获取分页数据  */ public List getScollData(int offest, int maxResult) {  List persons = new ArrayList();  SQLiteDatabase db = dbOpenHelper.getReadableDatabase();  Cursor cursor = db.query("person", null, null, null, null, null,"personid asc", offest + "," + maxResult);                //db.query(table, columns, selection, selectionArgs, groupBy, having, orderBy, limit);  while (cursor.moveToNext()) {   int personid = cursor.getInt(cursor.getColumnIndex("personid"));   String name = cursor.getString(cursor.getColumnIndex("name"));   String phone = cursor.getString(cursor.getColumnIndex("phone"));   persons.add(new Person(personid, name, phone));  }  cursor.close();  return persons; } public long getCount() {  SQLiteDatabase db = dbOpenHelper.getReadableDatabase();  Cursor cursor = db.query("person", new String[] { "count(*)" }, null, null, null, null, null);                //db.query(table, columns, selection, selectionArgs, groupBy, having, orderBy);  cursor.moveToFirst();  long result = cursor.getLong(0);  return result; }}