数据库的帮助类以及DAO层代码

数据库的帮助类以及DAO层代码

1.帮助类

public class BlackNumberHelper extends SQLiteOpenHelper{    public BlackNumberHelper(Context context) {        super(context, Constdb.DBNAME, null, Constdb.DBVERSION);    }    @Override    public void onCreate(SQLiteDatabase sqL) {        //创建黑名单数据库        sqL.execSQL("create table "+Constdb.BLACKNUMBERTABLE +" ( "+Constdb._ID+"  integer primary key autoincrement, "+Constdb._PHONE+" varchar(20), "+Constdb._MODE+" varchar(2))");    }    @Override    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {    }}

public class Constdb {    public static  final  String  DBNAME  = "blacknumber.db";//数据库的名字    public static  final  int  DBVERSION = 1;   //数据库的版本号    public  static  final  String  BLACKNUMBERTABLE = "blacknumbertable";    public  static  final  String  _ID  = "_id";    public static  final  String  _PHONE = "_phone";    public  static final  String  _MODE  ="_mode";}

2.DAO层代码

public class BlackNumberDao {    private final BlackNumberHelper mHelper;    //创建一个黑名单的dao层    public BlackNumberDao(Context context) {        mHelper = new BlackNumberHelper(context);    }    //创建一个添加的方法    public boolean inster(String phone, String mode) {        //获取一个可写的数据库        SQLiteDatabase dp = mHelper.getWritableDatabase();        ContentValues values = new ContentValues();        values.put(Constdb._PHONE, phone);        values.put(Constdb._MODE, mode);        long insert = dp.insert(Constdb.BLACKNUMBERTABLE, null, values);        dp.close();        if (insert != -1) {            return true;        } else {            return false;        }    }    //创建一个删除的方法    public boolean delete(String phone) {        SQLiteDatabase db = mHelper.getWritableDatabase();        int delete = db.delete(Constdb.BLACKNUMBERTABLE, Constdb._PHONE + "=?", new String[]{phone});        db.close();        if (delete != 0) {            return true;        } else {            return false;        }    }    //修改的方法    public boolean upDate(String phone, String mode) {        SQLiteDatabase db = mHelper.getWritableDatabase();        ContentValues values = new ContentValues();        values.put(Constdb._PHONE, phone);        values.put(Constdb._MODE, mode);        int update = db.update(Constdb.BLACKNUMBERTABLE, values, Constdb._PHONE + "=?", new String[]{phone});        db.close();        if (update != 0) {            return true;        } else {            return false;        }    }    //查询的方法    public List<BlackNumberBean> query(){        ArrayList<BlackNumberBean> lists = new ArrayList<>();        SQLiteDatabase db = mHelper.getReadableDatabase();        Cursor query = db.query(Constdb.BLACKNUMBERTABLE, new String[]{Constdb._PHONE, Constdb._MODE}, null, null, null, null, null);        while (query.moveToNext()){            BlackNumberBean bean = new BlackNumberBean();            //为每个对象赋值            bean.phone= query.getString(query.getColumnIndex(Constdb._PHONE));            bean.mode = query.getString(query.getColumnIndex(Constdb._MODE));            lists.add(bean);        }        db.close();        query.close();        return lists;    }    //创建查询一个的方法    public String find(String phone){        String mode = null;        SQLiteDatabase db = mHelper.getReadableDatabase();        Cursor query = db.query(Constdb.BLACKNUMBERTABLE, new String[]{Constdb._MODE}, Constdb._PHONE+"=?", new String[]{phone}, null, null, null);        while (query.moveToNext()){             mode = query.getString(query.getColumnIndex(Constdb._MODE));        }        return mode;    }    //分页查询数据库    public List<BlackNumberBean> findPart(int count ,int startIndex){        List<BlackNumberBean> lists=new ArrayList<>();        // 1得到一个可读的数据库,        SQLiteDatabase db = mHelper.getReadableDatabase();        Cursor cursor = db.rawQuery("select "+Constdb._PHONE+" , "+Constdb._MODE+"  from "+Constdb.BLACKNUMBERTABLE+" order by _id desc limit ? offset ? ", new String[]{String.valueOf(count), String.valueOf(startIndex)});        while (cursor.moveToNext()){            BlackNumberBean bean=new BlackNumberBean();            bean.mode = cursor.getString(cursor.getColumnIndex(Constdb._MODE));            bean.phone = cursor.getString(cursor.getColumnIndex(Constdb._PHONE));            lists.add(bean);        }        return lists;    }    //查询和数据库的个数    public int getCount(){        int count=0;        // 1得到一个可读的数据库        SQLiteDatabase db = mHelper.getReadableDatabase();        Cursor cursor = db.rawQuery("select count(*) from "+Constdb.BLACKNUMBERTABLE+" ",null);        while (cursor.moveToNext()){            count= cursor.getInt(0);        }        return count;    }