Shulou(Shulou.com)05/31 Report--

这篇文章主要讲解了"通过SQL语句查询需要的数据"，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习"通过SQL语句查询需要的数据"吧!

在main.xml中：

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 find(){

List all = new ArrayList() ; // 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 //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

MySQLiteDemo.this.mylayout.addView(listView);

}

}

}

感谢各位的阅读，以上就是"通过SQL语句查询需要的数据"的内容了，经过本文的学习后，相信大家对通过SQL语句查询需要的数据这一问题有了更深刻的体会，具体使用情况还需要大家实践验证。这里是，小编将为大家推送更多相关知识点的文章，欢迎关注!

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