利用Android中的SQLite进行CRUD

一、SQLite？

SQLite是一种轻量级的数据库，Android中自带有。

android可以借助SQLiteOpenHelper来对SQLite进行操作

二、效果图

三、代码编写与解析

1.编写操作系统的工具类DBHelper继承SQLiteOpenHelper

SQLiteOpenHelper是用来管理数据库的创建和版本的管理

package linys.util;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;/** *  * @Project: Android_SQLite * @Desciption:  * SQLiteOpenHelper * A helper class to manage database creation and version management * SQLiteOpenHelper 管理数据库的创建和版本的管理 * @Author: LinYiSong * @Date: 2011-3-25~2011-3-25 */public class DBHelp extends SQLiteOpenHelper {/** *  * @param context * @param name数据库文件名 * @param factory * @param version */public DBHelp(Context context, String name, CursorFactory factory,int version) {super(context, name, factory, version);}/** * Called when the database is created for the first time. * This is where the creation of tables and the initial population of the tables should happen */@Overridepublic void onCreate(SQLiteDatabase db) {System.out.println("SQLiteDatabase's OnCreate");db.execSQL("create table user(id int,name varchar(20))");}/** * upgrade：升级，数据库版本从1-->2会调用这个函数 */@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {System.out.println("upgrade");}}

2.编写Activity，对SQLite数据库进行操作

package linys.db;import linys.util.DBHelp;import android.app.Activity;import android.content.ContentValues;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;/** *  * @Project: Android_SQLite * @Desciption: SQLite是一种轻量级的数据库 * android可以借助SQLiteOpenHelper来对SQLite进行操作： *  * 操作类，继承SQLiteOpenHelper如DBHelp *  *  * adb:android debug bridge * android自带的调试工具，可以进入内核，进行操作 * adb shell 进入内核 * 编写的程序放在data/data对于的包（即我们在new出Program时指定的package *  * 如果程序有用到数据库，则数据库在database下 * 对数据进行操作前，先切换的sqlite3模式下：sqlite3 数据库名 *.schema可以查看数据库中创建的表格语句， *  * @Author: LinYiSong * @Date: 2011-3-10~2011-3-10 */public class SQLiteDemo extends Activity {    /** Called when the activity is first created. */private Button createDataBaseBtn;private Button updateDataBaseBtn;private Button insertBtn;private Button updateBtn;private Button queryBtn;private Button deleteBtn;DBHelp dbHelp;    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);                createDataBaseBtn=(Button)this.findViewById(R.id.createDatabase);        updateDataBaseBtn=(Button)this.findViewById(R.id.updateDatabase);        insertBtn=(Button)this.findViewById(R.id.insert);        updateBtn=(Button)this.findViewById(R.id.update);        queryBtn=(Button)this.findViewById(R.id.query);        deleteBtn=(Button)this.findViewById(R.id.delete);                //注册监听器        createDataBaseBtn.setOnClickListener(new CreateDBListener());        updateDataBaseBtn.setOnClickListener(new UpdateDBListener());        insertBtn.setOnClickListener(new InsertListener());        updateBtn.setOnClickListener(new UpdateListener());        queryBtn.setOnClickListener(new QueryListener());        deleteBtn.setOnClickListener(new DeleteListener());    }    class CreateDBListener implements OnClickListener{@Overridepublic void onClick(View v) {dbHelp=new DBHelp(SQLiteDemo.this,"linys",null,1);dbHelp.getWritableDatabase();}}        class UpdateDBListener implements OnClickListener{@Overridepublic void onClick(View v) {dbHelp=new DBHelp(SQLiteDemo.this,"linys",null,2);dbHelp.getWritableDatabase();}}            class InsertListener implements OnClickListener{@Overridepublic void onClick(View v) {//准备数据ContentValues content=new ContentValues();content.put("id", "12");content.put("name", "linys");//操作数据库dbHelp=new DBHelp(SQLiteDemo.this,"linys",null,2);SQLiteDatabase db=dbHelp.getWritableDatabase();db.insert("user", null, content);}}        class DeleteListener implements OnClickListener{@Overridepublic void onClick(View v) {//操作数据库dbHelp=new DBHelp(SQLiteDemo.this,"linys",null,2);SQLiteDatabase db=dbHelp.getWritableDatabase();db.delete("user","id=?",new String[]{"12"});}}        class UpdateListener implements OnClickListener{@Overridepublic void onClick(View v) {//准备数据ContentValues content=new ContentValues();content.put("id", "12");content.put("name", "linyisong");//操作数据库dbHelp=new DBHelp(SQLiteDemo.this,"linys",null,2);SQLiteDatabase db=dbHelp.getWritableDatabase();db.update("user", content, "id=?" ,new String[]{"12"});}}        class QueryListener implements OnClickListener{@Overridepublic void onClick(View v) {dbHelp=new DBHelp(SQLiteDemo.this,"linys",null,2);SQLiteDatabase db=dbHelp.getReadableDatabase();//Cursor游标相当于java中的IteratorCursor cursor=db.query("user", new String[]{"id","name"}, "id=?",new String[]{"12"}, null,null, null);while(cursor.moveToNext()){String id=cursor.getString(cursor.getColumnIndex("id"));String name=cursor.getString(cursor.getColumnIndex("name"));System.out.println("id: "+id+" name:"+name);}}}}

四、补充：调试adb

1.adb:android debug bridge
2.android自带的调试工具，可以进入内核，进行操作:adb shell 进入内核
3.编写的程序放在data/data对于的包（即我们在new出Program时指定的package)
4.如果程序有用到数据库，则数据库在database下
5.对数据进行操作前，先切换的sqlite3模式下：sqlite3 数据库名
6.标准的sql语句也用，另外.schema可以查看数据库中创建的表格语句

利用Android中的SQLite进行CRUD

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