欢迎来到Doc100.Net免费学习资源知识分享平台!
您的位置:首页 > 程序异常 >

透过sql语句查询

更新时间: 2014-01-05 02:08:03 责任编辑: Author_N1

 

通过SQL语句查询

 

 

 

 

在main.xml中:

 

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:id="@+id/mylayout"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:orientation="vertical"

    android:gravity="center_horizontal">

 

    <Button

        android:id="@+id/findBut"

        android:layout_marginTop="8dp"

        android:background="#0066ff"

        android:textColor="#ffffff"

        android:layout_width="100dp"

        android:layout_height="40dp"

        android:text="查询全部数据" />

 

</LinearLayout>

 

 

 

在MyDatabaseHelper.java类中:

 

package com.li.sqlite;

//数据库的辅助操作类

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteOpenHelper;

 

public class MyDatabaseHelper extends SQLiteOpenHelper {

  private static final String DATABASENAME = "liyewen.db" ;

  private static final int DATABASERVERSION = 1 ;  // 设置数据库的版本

  private static final String TABLENAME = "mytab" ;

 

  public MyDatabaseHelper(Context context) {  // 用户最关心的也肯定只是Context

     super(context, DATABASENAME, null, DATABASERVERSION);

  }

 

  @Override

  public void onCreate(SQLiteDatabase db) { // 创建数据表

     String sql = "CREATE TABLE " + TABLENAME + "("

         + "id    INTEGER       PRIMARY KEY ,"   // 在SQLite中设置为Integer、PRIMARY KEY则ID自动增长

         + "name   VARCHAR(50)   NOT NULL ,"

         + "birthday DATE NOT    NULL" + ")";

     db.execSQL(sql) ;  // 执行SQL

     System.out.println("****************** 创建:onCreate()。");

  }

 

  @Override

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

     String sql = "DROP TABLE IF EXISTS " + TABLENAME ;

     db.execSQL(sql) ;

     System.out.println("****************** 更新:onUpgrade()。");

     this.onCreate(db) ;

  }

 

}

 

 

 

 

在MytabCursor.java类中:

 

package com.li.sqlite;

 

import java.util.ArrayList;

import java.util.List;

 

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

 

public class MytabCursor {

  private static final String TABLENAME = "mytab" ;

  private SQLiteDatabase db = null ;

  public MytabCursor(SQLiteDatabase db) {

     this.db = db ;

  }

  public List<String> find(){

     List<String> all = new ArrayList<String>() ; // 此时只是String

     String sql = "SELECT id,name,birthday FROM " + TABLENAME ;

     Cursor result = this.db.rawQuery(sql, null); // 执行查询语句

     for (result.moveToFirst(); !result.isAfterLast(); result.moveToNext()) { // 采用循环的方式检索数据

       all.add("【" + result.getInt(0) + "】" + " " + result.getString(1)

            + "," + result.getString(2));

     }

     this.db.close() ;

     return all ;

  }

}

 

 

 

 

 

 

在MySQLiteDemo.java中:

 

package com.li.sqlite;

 

import android.app.Activity;

import android.database.sqlite.SQLiteOpenHelper;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.ArrayAdapter;

import android.widget.Button;

import android.widget.LinearLayout;

import android.widget.ListView;

 

public class MySQLiteDemo extends Activity {

  private Button findBut = null;

  private SQLiteOpenHelper helper = null;

  private LinearLayout mylayout = null;

  @Override

  public void onCreate(Bundle savedInstanceState) {

     super.onCreate(savedInstanceState);

     super.setContentView(R.layout.main);

     this.findBut = (Button)super.findViewById(R.id.findBut);

     this.mylayout = (LinearLayout)super.findViewById(R.id.mylayout);

     this.findBut.setOnClickListener(new OnClickListenerImpl());

  }

  private class OnClickListenerImpl implements OnClickListener{

     public void onClick(View v) {

       MySQLiteDemo.this.helper = new MyDatabaseHelper(MySQLiteDemo.this);

       ListView listView = new ListView(MySQLiteDemo.this);

       listView.setAdapter( //设置数据

            new ArrayAdapter<String>  //所有的数据是字符串

            (MySQLiteDemo.this,       //上下文

            android.R.layout.simple_list_item_1, //列表显示的布局

            new MytabCursor(     //实例化查询

            MySQLiteDemo.this.helper.getReadableDatabase())  //取得SQLiteDatabase对象

            .find()));    //调用find()方法,返回List<String>

       MySQLiteDemo.this.mylayout.addView(listView);

     }

  }

}

 

 



 

上一篇:上一篇
下一篇:下一篇

 

随机推荐程序问答结果

 

 

如对文章有任何疑问请提交到问题反馈,或者您对内容不满意,请您反馈给我们DOC100.NET论坛发贴求解。
DOC100.NET资源网,机器学习分类整理更新日期::2014-01-05 02:08:03
如需转载,请注明文章出处和来源网址:http://www.doc100.net/bugs/t/6017/
本文WWW.DOC100.NET DOC100.NET版权所有。