sqlite 版本升级及数据库操作类（二）

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数据库操作工具类（增删改查）

/** * 保存数据到数据库 */public void savaShowData(String ctype, String title, String source) {    synchronized (mySqlitehelper) {        if (!writableDatabase.isOpen()) {            writableDatabase = mySqlitehelper.getWritableDatabase();        }        writableDatabase.beginTransaction();        try {            ContentValues contentValues = new ContentValues();            contentValues.put("ctype", ctype);            contentValues.put("title", title);            contentValues.put("source", source);            writableDatabase.insert("NewsShow", null, contentValues);            writableDatabase.setTransactionSuccessful();        } catch (Exception e) {            e.printStackTrace();        } finally {            writableDatabase.endTransaction();            writableDatabase.close();        }    }}

/** * 获取数据库缓存的前30条数据 * @return */public List getshowDate() {    synchronized (mySqlitehelper) {        if (!writableDatabase.isOpen()) {            writableDatabase = mySqlitehelper.getWritableDatabase();        }        Cursor cursor = writableDatabase.query("NewsShow", null, null, null, null, null, null, null);        Cursor queryCursor = null;        try {            if (cursor.getCount() > 0) {                int limitNum;                if (cursor.getCount() <= 30) limitNum = cursor.getCount();                else limitNum = cursor.getCount() - (cursor.getCount() - 30);                //select * from 表名 limit 0,10;                String sql = "select * from NewsShow limit " + 0 + "," + limitNum;                queryCursor = writableDatabase.rawQuery(sql, null);                showList = new ArrayList<News>();                while (queryCursor.moveToNext()) {                    String ctype = queryCursor.getString(queryCursor.getColumnIndex("ctype"));                    String title = queryCursor.getString(queryCursor.getColumnIndex("title"));                    String source = queryCursor.getString(queryCursor.getColumnIndex("source"));                    showList.add(new News(ctype, title, source, source_type, type, detail_a, listImages, data_id, false, isRead));                }                return showList;            } else {                return null;            }        } catch (Exception e) {            e.printStackTrace();        } finally {            if (null != queryCursor)                queryCursor.close();            cursor.close();        }    }    return showList;}
/** * 删除数据库指定数据 (_id) * @param number */public void deleteData(int number) {    synchronized (mySqlitehelper) {        if (!writableDatabase.isOpen()) {            writableDatabase = mySqlitehelper.getWritableDatabase();        }        try {            writableDatabase.delete("NewsShow", "_id=?", new String[]{String.valueOf(number)});            writableDatabase.close();        } catch (Exception e) {            e.printStackTrace();            LogUtils.e(TAG, "delete fail" + e);        } finally {            writableDatabase.close();        }    }}
/** * 清空数据库并重置id */public void deleteShowData() {    synchronized (mySqlitehelper) {        if (!writableDatabase.isOpen()) {            writableDatabase = mySqlitehelper.getWritableDatabase();        }        try {            String sql = "DELETE FROM " + "NewsShow" + ";";            writableDatabase.execSQL(sql);            String sqlRevert = "update sqlite_sequence set seq=0 where name='" + "NewsShow" + "'";            writableDatabase.execSQL(sqlRevert);            writableDatabase.close();        } catch (Exception e) {            e.printStackTrace();        } finally {            writableDatabase.close();        }    }}

/** *  查询数据库是否已存在某条数据 */public String queryDate(String detail_a) {    String url = null;    synchronized (mySqlitehelper) {        if (!writableDatabase.isOpen()) {            writableDatabase = mySqlitehelper.getWritableDatabase();        }        String sql = "select detail_a from NewsShow where detail_a='" + detail_a + "'";        Cursor cursor = writableDatabase.rawQuery(sql, null);        try {            while (cursor.moveToNext()) {                url = cursor.getString(cursor.getColumnIndex("detail_a"));            }        } catch (Exception e) {            e.printStackTrace();            LogUtils.e(TAG, " query savaSqlite is null:" + e);        } finally {            cursor.close();            writableDatabase.close();        }    }    return url;}

/** * 更新数据库表中某条数据 */public void updataHasRead(String detialUrl) {    if (!detialUrl.equals(queryDate(detialUrl))) {//先查询 再去更新已读        return;    }    synchronized (mySqlitehelper) {        if (!writableDatabase.isOpen()) {            writableDatabase = mySqlitehelper.getWritableDatabase();        }        try {            ContentValues values = new ContentValues();            values.put("isRead", "Y");            int isRead = writableDatabase.update("NewsShow", values, "detail_a=?", new String[]{detialUrl});        } catch (Exception e) {            e.printStackTrace();            LogUtils.e(TAG, "updataHasRead :" + e);        } finally {            writableDatabase.close();        }    }}

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