【Android学习笔记】SQLite数据库存储

因为前面提到xml存储更改文件很麻烦的缘故，最终还是选择了使用数据库存储

一试才觉十分的方便，速度也快

上源码：

public class DBHelper  extends SQLiteOpenHelper{    private final static String DATABASE_NAME="fanliao_db";    private final static int DATABASE_VERSION=1;    private final static String TABLE_NAME="fanliao_chat";    public final static String CHAT_ID="_id";     public final static String CHAT_Name="chatname";    public final static String CHAT_Info="chatinfo";    public final static String CHAT_Time="chattime";            public DBHelper(Context context)    {        super(context, DATABASE_NAME,null, DATABASE_VERSION);    }                 @Override    public void onCreate(SQLiteDatabase db) {       //CREATE TABLE fanliao_chat( _id  INTEGER PRIMARY KEY  AUTOINCREMENT,    // chatname TEXT, chattime TEXT, chatinfo TEXT);    String sql="CREATE TABLE "+TABLE_NAME+"("+CHAT_ID+"  INTEGER PRIMARY KEY  AUTOINCREMENT,"        +CHAT_Name+" TEXT, "+CHAT_Time+" TEXT, "+CHAT_Info+" TEXT);";        db.execSQL(sql);        System.out.println(sql);             }    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {        String sql=" DROP TABLE IF EXISTS "+TABLE_NAME;        db.execSQL(sql);        onCreate(db);        System.out.println(sql);    }    public Cursor select()    {        SQLiteDatabase db=this.getReadableDatabase();        Cursor cursor=db.query(TABLE_NAME, null, null, null, null, null,  " _id asc");        return cursor;    }        public long insert(String chatname, String chattime, String chatinfo)    {        SQLiteDatabase db=this.getWritableDatabase();        ContentValues cv=new ContentValues();         cv.put(CHAT_Name, chatname);        cv.put(CHAT_Time, chattime);        cv.put(CHAT_Info, chatinfo);        long row=db.insert(TABLE_NAME, null, cv);        return row;    }        public void delete(int id)    {        SQLiteDatabase db=this.getWritableDatabase();        String where=CHAT_ID+"=?";        String[] whereValue={Integer.toString(id)};        db.delete(TABLE_NAME, where, whereValue);    }        public void update(int id,String chatname,String chattime, String chatinfo)    {        SQLiteDatabase db=this.getWritableDatabase();        String where=CHAT_ID+"=?";        String[] whereValue={Integer.toString(id)};        ContentValues cv=new ContentValues();         cv.put(CHAT_Name, chatname);        cv.put(CHAT_Time, chattime);        cv.put(CHAT_Info, chatinfo);        db.update(TABLE_NAME, cv, where, whereValue);    }        public void delall(){    SQLiteDatabase db=this.getReadableDatabase();    String sql=" DROP TABLE IF EXISTS "+TABLE_NAME;        db.execSQL(sql);        onCreate(db);    }        }

用后才觉得经常修改的数据本就应用数据库的，

形如“聊天记录”这种虽没有十分复杂的存储结构，也是适宜存在表中，

而xml大概多是用以传输数据或存储少量不常用改动的数据把~