SQL学习笔记之数据库专题（二）：Android下SQL数据库开发

package com.example.freedomsql.db;

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

/**
 * @ClassName: FreedomDB
 * @author victor_freedom (x_freedom_reddevil@126.com)
 * @createddate 2015-1-10 下午2:49:15
 * @Description: TODO
 */
public class FreedomDB extends SQLiteOpenHelper {

	public FreedomDB(Context context) {
		// 参数依次为：上下文，数据库名称，游标工厂一般为NULL,数据库版本号，升级的时候需要更改
		super(context, "freedom.db", null, 1);
	}

	/**
	 * 第一次创建数据库的时候触发该方法
	 */
	@Override
	public void onCreate(SQLiteDatabase db) {
		//sql语句详情请参考该系列文章第一篇
		db.execSQL("create table person (id integer primary key autoincrement,name varchar(20),number varchar(20))");
	}

	/**
	 * 数据库版本号变化的时候触发该方法
	 */
	@Override
	public void onUpgrade(SQLiteDatabase db, int oldversion, int newversion) {
		// if (oldversion == 1 && newversion == 2) {
		// db.execSQL("alter table person add nickname varchar(20)");
		// }
	}
}

package com.example.freedomsql.db.dao;

import java.util.ArrayList;
import java.util.List;

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

import com.example.freedomsql.bean.Person;
import com.example.freedomsql.db.FreedomDB;

/**
 * @ClassName: PersonDao
 * @author victor_freedom (x_freedom_reddevil@126.com)
 * @createddate 2015-1-10 下午2:30:24
 * @Description: TODO
 */
public class PersonDao {
	private FreedomDB dbHelper;

	public PersonDao(Context context) {
		dbHelper = new FreedomDB(context);

	}

	/**
	 * @Title: add
	 * @Description:增加
	 * @param name
	 * @param number
	 * @throws
	 */
	public void add(String name, String number) {
		SQLiteDatabase db = dbHelper.getWritableDatabase();
		db.execSQL("insert into person(name,number) values (?,?)",
				new Object[] { name, number });
		db.close();
		// 系统API
		// ContentValues = values = new ContentValues();
		// values.put("name",name);
		// values.put("number",number);
		// long id = db.insert(table（表名)，null,values(数据))；
		// return id;

	}

//	/**
//	 * @Title: add
//	 * @Description: 升级后的增加方法
//	 * @param name
//	 * @param number
//	 * @param nickname
//	 * @throws
//	 */
//	public void add(String name, String number, String nickname) {
//		SQLiteDatabase db = dbHelper.getWritableDatabase();
//		db.execSQL("insert into person(name,number,nickname) values (?,?,?)",
//				new Object[] { name, number, nickname });
//		db.close();
//		// 系统API
//		// ContentValues = values = new ContentValues();
//		// values.put("name",name);
//		// values.put("number",number);
//		// long id = db.insert(table（表名)，null,values(数据))；
//		// return id;
//
//	}

	/**
	 * @Title: delete
	 * @Description: 删除
	 * @param name
	 * @throws
	 */
	public void delete(String name) {
		SQLiteDatabase db = dbHelper.getWritableDatabase();
		db.execSQL("delete from person where name=?", new Object[] { name });

		// 系统API
		// int number=db.delete("person","name=?",new String[]{name});
		db.close();
	}

	/**
	 * @Title: updata
	 * @Description: 更新
	 * @param name
	 * @param newnumber
	 * @throws
	 */
	public void updata(String name, String newnumber) {
		SQLiteDatabase db = dbHelper.getWritableDatabase();
		db.execSQL("update person set number=? where name=?", new Object[] {
				newnumber, name });
		// 系统API
		// ContentValues values = new ContentValues();
		// values.put("number", newnumber);
		// int num = db.update("person", values, "name=?", new String[] { name
		// });
		db.close();
	}

	/**
	 * @Title: find
	 * @Description: 查询
	 * @param name
	 * @return
	 * @throws
	 */
	public boolean find(String name) {
		SQLiteDatabase db = dbHelper.getReadableDatabase();

		Cursor cursor = db.rawQuery("select * from person where name =?",
				new String[] { name });
		// 系统API
		// Cursor cursor = db.query(table(表名)，null,"name=?",new
		// String[](name),null,null,null);
		boolean result = cursor.moveToNext();
		cursor.close();
		db.close();
		return result;

	}

	/**
	 * @Title: findAll
	 * @Description:查询
	 * @return
	 * @throws
	 */
	public List<Person> findAll() {
		List<Person> persons = new ArrayList<Person>();
		SQLiteDatabase db = dbHelper.getReadableDatabase();
		Cursor cursor = db.rawQuery("select * from person", null);
		// 系统API
		// Cursor cursor= db.query("Person",new
		// String[]{"name","id","number"},null,null,null,null,null);

		while (cursor.moveToNext()) {
			int id = cursor.getInt(cursor.getColumnIndex("id"));
			String name = cursor.getString(cursor.getColumnIndex("name"));
			String number = cursor.getString(cursor.getColumnIndex("number"));
			// String nickname = cursor.getString(cursor
			// .getColumnIndex("nickname"));
			Person p = new Person(id, name, number);
			persons.add(p);
		}
		cursor.close();
		db.close();
		return persons;

	}
}

4、主Activity内代码

package com.example.freedomsql;

import com.example.freedomsql.db.dao.PersonDao;

import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.os.Build;

public class MainActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		PersonDao dao = new PersonDao(getBaseContext());
		dao.add("汤老板", "110");
		dao.add("郭大侠", "119");
		// dao.add("汤老板1", "110", "汤老板");
		// dao.add("郭大侠1", "119", "郭女侠");
	}
}