一、数据库操作

package com.ping.db;

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteDatabase.CursorFactory;

import android.database.sqlite.SQLiteOpenHelper;

/**

* @describe

*/

public class SQLiteTool extends SQLiteOpenHelper {

private static final String DB_NAME = "medicalscience.db"; // 数据库文件名

private static final int VERSION = 1;// 数据库版本

public static SQLiteTool newInstance(Context context) {

return new SQLiteTool(context, DB_NAME, null, VERSION);

}

private SQLiteTool(Context context, String name, CursorFactory factory, int version) {

super(context, name, factory, version);

}

@Override

public void onCreate(SQLiteDatabase db) {

db.execSQL(DBTCollect.createTableSQL());//有需要创建表时，可以在这添加

}

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {//当数据库版本变大时调用

onCreate(db);

}

}

二、数据库管理类

package com.ping.db;

import java.util.concurrent.atomic.AtomicInteger;

import android.annotation.SuppressLint;

import android.database.sqlite.SQLiteDatabase;

import android.os.Build;

import com.ping.MyApplication;

/**

* @describe

*/

public class DBManager {

private AtomicInteger dbOpenCount = new AtomicInteger();//计数器

private static DBManager instance;

private static SQLiteTool sqlLiteTool;

private SQLiteDatabase database;

public static synchronized DBManager getInstance() {

if (instance == null) {

synchronized (DBManager.class) {

if (instance == null) {

instance = new DBManager();

}

}

}

return instance;

}

private DBManager() {

sqlLiteTool = SQLiteTool.newInstance(MyApplication.getInstance().getApplicationContext());

}

@SuppressLint("NewApi")

public synchronized SQLiteDatabase openDatabase() {

if (dbOpenCount.incrementAndGet() == 1) {

database = sqlLiteTool.getWritableDatabase();

if (Build.VERSION.SDK_INT >= 11) {

database.enableWriteAheadLogging();// 允许读写同时进行

}

}

return database;

}

public synchronized void closeDatabase() {

if (dbOpenCount.decrementAndGet() == 0) {

database.close();

database = null;

}

}

}

三、数据增删改查

package com.ping.db;

import java.util.ArrayList;

import android.content.ContentValues;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

/**

* @describe

*/

public class DBTCollect {

public static final String TNAME = "Tcollect";

// 创建表的语句

public static String createTableSQL() {

return "CREATE TABLE IF NOT EXISTS " + TNAME + " (kid INTEGER PRIMARY KEY AUTOINCREMENT, id TEXT, title TEXT)";

}

// 删除表的语句

public static String deleteTabelSQL() {

return "DROP TABLE IF EXISTS " + TNAME;

}

//查询数据是否存在

public static boolean isCollected(String id) {

boolean isCollected = false;

SQLiteDatabase db = DBManager.getInstance().openDatabase();//获得SQLiteDatabase对象

String sql = "select * from " + TNAME + " where id = '" + id + "'";

Cursor cursor = db.rawQuery(sql, null);

if (cursor.getCount() > 0) {

isCollected = true;

}

cursor.close();

DBManager.getInstance().closeDatabase();//关闭

return isCollected;

}

// 删除数据

public static void deleteCollect(String mid) {

SQLiteDatabase db = DBManager.getInstance().openDatabase();

db.delete(TNAME, "id = ?", new String[] { id });

DBManager.getInstance().closeDatabase();

}

//增加数据

public static void addCollect(Object obj) {

SQLiteDatabase db = DBManager.getInstance().openDatabase();

ContentValues cv = new ContentValues();

cv.put("id", obj.id);

cv.put("title", obj.title);

db.insert(TNAME, null, cv);

DBManager.getInstance().closeDatabase();

}

//查询数据

public static ArrayList getAllCollect() {

SQLiteDatabase db = DBManager.getInstance().openDatabase();

Cursor cursor = db.query(TNAME, null, null, null, null, null, null);

ArrayList objs = new ArrayList();

while (cursor.moveToNext()) {

Object obj = new Object();

obj.id = cursor.getString(cursor.getColumnIndex("id"));

obj.title = cursor.getString(cursor.getColumnIndex("title"));

objs.add(obj);

}

cursor.close();

DBManager.getInstance().closeDatabase();

return objs;

}

}