SQLite数据库的添删改查

    还是那句话，经常重复的代码要总结起来

1.首先建一个person实例:

Person.java

package morgen.domain;public class Person {    private Integer id;    private String name;    private String phone;    public Integer getId() {        return id;    }    public void setId(Integer id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getPhone() {        return phone;    }    public void setPhone(String phone) {        this.phone = phone;    }    public Person(Integer id, String name, String phone) {        this.id = id;        this.name = name;        this.phone = phone;    }    public Person(String name, String phone) {        this.name = name;        this.phone = phone;    }    @Override    public String toString() {        return "Person [id=" + id + ", name=" + name + ", phone=" + phone + "]";    }    }

2.接着创建数据库文件和表

DBOpenHelper.java

package morgen.db;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;public class DBOpenHelper extends SQLiteOpenHelper {    public DBOpenHelper(Context context) {        super(context, "morgen.db", null, 2);    }    @Override    public void onCreate(SQLiteDatabase db) {        db.execSQL("CREATE TABLE person(id integer primary key autoincrement, name varchar(20))");    }    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {        db.execSQL("ALTER TABLE person ADD phone VARCHAR(12) NULL");    }}

3.对数据库进行操作

PersonService.java

package morgen.service;import java.util.ArrayList;import java.util.List;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import morgen.db.DBOpenHelper;import morgen.domain.Person;public class PersonService {    private DBOpenHelper dbOpenHelper;        public PersonService(Context context){        dbOpenHelper = new DBOpenHelper(context);    }    /**     * 保存数据     * @param person     */    public void save(Person person){        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();        db.execSQL("insert into person(name,phone) values(?,?)",                new Object[]{person.getName(), person.getPhone()});        //db.close();    }    /**     * 删除记录     * @param id 记录ID     */    public void delete(Integer id){        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();        db.execSQL("delete from person where id=?", new Object[]{id});    }    /**     * 更新记录     * @param person     */    public void update(Person person){        SQLiteDatabase db = dbOpenHelper.getWritableDatabase();        db.execSQL("update person set name=?,phone=? where id=?",                new Object[]{person.getName(), person.getPhone(), person.getId()});    }    /**     * 获取记录     * @param id 记录id     * @return     */    public Person find(Integer id){        SQLiteDatabase db = dbOpenHelper.getReadableDatabase();        Cursor cursor = db.rawQuery("select * from person where id=?", new String[]{id.toString()});        if(cursor.moveToFirst()){            String phone = cursor.getString(cursor.getColumnIndex("phone"));            String name = cursor.getString(cursor.getColumnIndex("name"));            cursor.close();            return new Person(id, name, phone);        }        return null;    }    /**     * 分页获取记录     * @param offset 跳过前面多少条记录     * @param maxResult 每页获取的记录数     * @return     */    public List<Person> getScrollData(int offset, int maxResult){        List<Person> persons = new ArrayList<Person>();        SQLiteDatabase db = dbOpenHelper.getReadableDatabase();        Cursor cursor = db.rawQuery("select * from person order by id asc limit ?,?",                new String[]{String.valueOf(offset), String.valueOf(maxResult)});                while(cursor.moveToNext()){            int id = cursor.getInt(cursor.getColumnIndex("id"));            String phone = cursor.getString(cursor.getColumnIndex("phone"));            String name = cursor.getString(cursor.getColumnIndex("name"));            persons.add(new Person(id, name, phone));        }        cursor.close();        return persons;    }    /**     * 获取记录总数     * @return     */    public long getCount(){        SQLiteDatabase db = dbOpenHelper.getReadableDatabase();        Cursor cursor = db.rawQuery("select count(*) from person", null);        cursor.moveToFirst();        long count = cursor.getLong(0);        cursor.close();        return count;    }}