SqLite封转工具类

package com.cz.hello.utils;import java.util.ArrayList;import java.util.List;import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.SQLException;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import com.cz.hello.model.CityInfo;public class Db {private static final StringDB_NAME = "city.db";private static final int DB_VERSION = 1;private static Context mContext = null;private SQLiteDatabase mSQLiteDatabase= null;private DatabaseHelper mDatabaseHelper= null;private static final StringTABLE_CITY        = "table_city";   //城市表public static final StringKEY_ID           = "_id";         //数据idpublic static final StringKEY_CITY_NAME     = "city_name";    //城市名称public static final StringKEY_ADD_TIME     = "add_time";    //插入时间private static final StringTABLE_CITY_CREATE = "CREATE TABLE " + TABLE_CITY     + " (" + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"     + KEY_ADD_TIME  + " datetime default (datetime('now', 'localtime')),"        + KEY_CITY_NAME + " TEXT)" ;private static class DatabaseHelper extends SQLiteOpenHelper{DatabaseHelper(Context context){super(context, DB_NAME, null, DB_VERSION);}@Overridepublic void onCreate(SQLiteDatabase db){db.execSQL(TABLE_CITY_CREATE);}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion){db.execSQL("DROP TABLE IF EXISTS notes");onCreate(db);}}public Db(Context context){mContext = context;}public void open() throws SQLException{mDatabaseHelper = new DatabaseHelper(mContext);mSQLiteDatabase = mDatabaseHelper.getWritableDatabase();}public void close(){mDatabaseHelper.close();}/** * 插入一条城市数据 */public void insertCityData(String cityName){if(Utils.isEmpty(cityName)){return;}open();ContentValues initialValues = new ContentValues();initialValues.put(KEY_CITY_NAME, cityName);Cursor cursor = mSQLiteDatabase.query(TABLE_CITY, null, KEY_CITY_NAME+"=?", new String[]{cityName}, null, null, null);if (cursor.moveToNext()) {mSQLiteDatabase.update(TABLE_CITY, initialValues, KEY_CITY_NAME+"=?", new String[]{cityName});}else{mSQLiteDatabase.insert(TABLE_CITY, null, initialValues);}cursor.close();close();}/** * 获取所有城市列表数据 */public List<CityInfo> fetchAllCityData(){List<CityInfo> list = new ArrayList<CityInfo>();open();Cursor cursor = mSQLiteDatabase.query(TABLE_CITY, new String[] {KEY_ID, KEY_CITY_NAME}, null, null, null, null, KEY_ADD_TIME+" desc");while (cursor.moveToNext()) {CityInfo city = new CityInfo();city.cityname = cursor.getString(cursor.getColumnIndex(KEY_CITY_NAME));city.id = cursor.getString(cursor.getColumnIndex(KEY_ID));list.add(city);}cursor.close();close();return list;}/** * @author chenzheng * @since 2014-7-26 * @Description: 根据id删除数据 * @throws * @param id * @return * boolean */public void deleteCityData(String id){open();mSQLiteDatabase.delete(TABLE_CITY, KEY_ID + "=" + id, null);  close();  }}
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