Android SQLite

package org.crazyit.db;

import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.CursorAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;

/**
 * Description:
 * <br/>site: <a href="http://www.crazyit.org">crazyit.org</a>
 * <br/>Copyright (C), 2001-2014, Yeeku.H.Lee
 * <br/>This program is protected by copyright laws.
 * <br/>Program Name:
 * <br/>Date:
 * @author  Yeeku.H.Lee [email protected]
 * @version  1.0
 */
public class DBTest extends Activity
{
	SQLiteDatabase db;
	Button bn = null;
	ListView listView;

	@Override
	public void onCreate(Bundle savedInstanceState)
	{
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		// 创建或打开数据库（此处需要使用绝对路径）
		db = SQLiteDatabase.openOrCreateDatabase(
			this.getFilesDir().toString()
			+ "/my.db3", null); // ①
		listView = (ListView) findViewById(R.id.show);
		bn = (Button) findViewById(R.id.ok);
		bn.setOnClickListener(new OnClickListener()
		{
			@Override
			public void onClick(View source)
			{
				// 获取用户输入
				String title = ((EditText) findViewById(
					R.id.title)).getText().toString();
				String content = ((EditText) findViewById(R.id.content))
					.getText().toString();
				try
				{
					insertData(db, title, content);
					Cursor cursor = db.rawQuery("select * from news_inf"
						, null);
					inflateList(cursor);
				}
				catch (SQLiteException se)
				{
					// 执行DDL创建数据表
					db.execSQL("create table news_inf(_id integer"
						+ " primary key autoincrement,"
						+ " news_title varchar(50),"
						+ " news_content varchar(255))");
					// 执行insert语句插入数据
					insertData(db, title, content);
					// 执行查询
					Cursor cursor = db.rawQuery("select * from news_inf"
						, null);
					inflateList(cursor);
				}
			}
		});
	}

	private void insertData(SQLiteDatabase db
		, String title, String content) //②
	{
		// 执行插入语句
		db.execSQL("insert into news_inf values(null , ? , ?)"
			, new String[] {title, content });
	}

	private void inflateList(Cursor cursor)
	{
		// 填充SimpleCursorAdapter
		SimpleCursorAdapter adapter = new SimpleCursorAdapter(
			DBTest.this,
			R.layout.line, cursor,
			new String[] { "news_title", "news_content" }
			, new int[] {R.id.my_title, R.id.my_content },
			CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER); //③
		// 显示数据
		listView.setAdapter(adapter);
	}

	@Override
	public void onDestroy()
	{
		super.onDestroy();
		// 退出程序时关闭SQLiteDatabase
		if (db != null && db.isOpen())
		{
			db.close();
		}
	}
}