android 随手记 SQLITE代码直接能用

1：需要一个辅助类

     package com.dspsemi.im.receiver;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHelper extends SQLiteOpenHelper {

   private static final String DB_NAME = "friend.db";
   private static final String TBL_NAME = "friends";

   public final static String CREATE_TBL = "create table friends( name varchar(20))";
   private SQLiteDatabase db;

   public DatabaseHelper(Context c) {
       super(c, DB_NAME, null, 2);
   }

   @Override
   public void onCreate(SQLiteDatabase db) {
       this.db = db;
       db.execSQL(CREATE_TBL);
   }

   public void insert(ContentValues values) {
       if (db == null) {
           db = getWritableDatabase();
       }
       db.insert(TBL_NAME, null, values);
       db.close();
   }

   public Cursor query() {
       if (db == null)
           db = getWritableDatabase();
       Cursor c = db.query(TBL_NAME, null, null, null, null, null, null);
       return c;
   }

   public void del(String nowtime) {
       if (db == null) {
           db = getWritableDatabase();
       }

       int temp = db.delete(TBL_NAME, "nowtime=? ", new String[] { nowtime });

       System.out.print("delete result = " + temp);
   }

   public void close() {
       if (db != null)
           db.close();
   }

   @Override
   public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

   }

   // public Cursor execSql(String sql){
   // Cursor c = db.execSQL(sql);
   // }

}

二就是调用方法

插入和查询

    private void addFriend(String friendName) {
       DatabaseHelper helper = new DatabaseHelper(MainActivity.this);
       try {
           ContentValues values = new ContentValues();

           values.put("name", friendName);

           helper.insert(values);
       } catch (Exception e) {
       } finally {
           helper.close();
       }
   }

   private void queryFriend() {
       DatabaseHelper dh = new DatabaseHelper(this);
       Cursor cur = dh.query();

       for (cur.moveToFirst(); !cur.isAfterLast(); cur.moveToNext()) {

           String nametemp = cur.getString(cur.getColumnIndex("name"));

       //   Log.i("test", "naem" + nametemp);
           FriendNameList.add(nametemp);

       }
       mHandler.sendEmptyMessage(54);

   }

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