android SQLite的CRUD

mwjhw216

　　activity12.java
package com.wansha;import android.app.Activity;import android.content.ContentValues;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import com.wansha.db.DatabaseHelper;public class Activity12 extends Activity {private Button createDatabase;private Button updateDatabase;private Button insert;private Button update;private Button read;private Button delete;/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);this.createDatabase = (Button)this.findViewById(R.id.createDatabase);this.createDatabase.setOnClickListener(new CreateDatabaseListener());this.updateDatabase = (Button)this.findViewById(R.id.updateDatabase);this.updateDatabase.setOnClickListener(new UpdateDatabaseListener());this.insert = (Button)this.findViewById(R.id.insert);this.insert.setOnClickListener(new InsertListener());this.update = (Button)this.findViewById(R.id.update);this.update.setOnClickListener(new UpdateListener());this.read = (Button)this.findViewById(R.id.read);this.read.setOnClickListener(new ReadListener());this.delete = (Button)this.findViewById(R.id.delete);this.delete.setOnClickListener(new DeleteListener());}class CreateDatabaseListener implements OnClickListener{@Overridepublic void onClick(View v) {SQLiteOpenHelper sqlite = new DatabaseHelper(Activity12.this,"sharp");sqlite.getReadableDatabase();}}class UpdateDatabaseListener implements OnClickListener{@Overridepublic void onClick(View v) {System.out.println("UpdateDatabaseListener  is invoked !!!");SQLiteOpenHelper sqlite = new DatabaseHelper(Activity12.this,"sharp",2);sqlite.getReadableDatabase();}}class InsertListener implements OnClickListener{@Overridepublic void onClick(View v) {SQLiteOpenHelper sqlite = new DatabaseHelper(Activity12.this,"sharp");SQLiteDatabase database = sqlite.getWritableDatabase();ContentValues values = new ContentValues();values.put("username", "xiaopeng");database.insert("sharp", null, values);}}class UpdateListener implements OnClickListener{@Overridepublic void onClick(View v) {SQLiteOpenHelper sqlite = new DatabaseHelper(Activity12.this,"sharp");SQLiteDatabase database = sqlite.getWritableDatabase();ContentValues values = new ContentValues();values.put("username", "pengpeng");database.update("sharp", values, "id=?", new String[]{"2"});}}class ReadListener implements OnClickListener{@Overridepublic void onClick(View v) {SQLiteOpenHelper sqlite = new DatabaseHelper(Activity12.this,"sharp");SQLiteDatabase database = sqlite.getWritableDatabase();Cursor cursor = database.query("sharp", new String[]{"id","username"}, null, null, null, null, null);while(cursor.moveToNext()){String username = cursor.getString(cursor.getColumnIndex("username"));System.out.println("username---->" + username);}}}class DeleteListener implements OnClickListener{@Overridepublic void onClick(View v) {SQLiteOpenHelper sqlite = new DatabaseHelper(Activity12.this,"sharp");SQLiteDatabase database = sqlite.getWritableDatabase();database.delete("sharp", "id=?", new String[]{"1"});}}}
main.xml<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="fill_parent"android:layout_height="fill_parent"android:orientation="vertical" ><Button android:id="@+id/createDatabase"android:layout_width="fill_parent"android:layout_height="wrap_content"android:text="创建数据库"/><Button android:id="@+id/updateDatabase"android:layout_width="fill_parent"android:layout_height="wrap_content"android:text="更新数据库"/><Button android:id="@+id/insert"android:layout_width="fill_parent"android:layout_height="wrap_content"android:text="插入数据"/><Button android:id="@+id/update"android:layout_width="fill_parent"android:layout_height="wrap_content"android:text="更新数据"/><Button android:id="@+id/read"android:layout_width="fill_parent"android:layout_height="wrap_content"android:text="读取数据"/><Button android:id="@+id/delete"android:layout_width="fill_parent"android:layout_height="wrap_content"android:text="删除数据"/></LinearLayout>

　　db.execSQL("create table sharp(id integer primary key autoincrement, username varchar(255))");
　　创建自增长ID
　　

　　DatebaseHelper.java
package com.wansha.db;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;public class DatabaseHelper extends SQLiteOpenHelper{private static final int VERSION = 1;public DatabaseHelper(Context context, String name, CursorFactory factory,int version) {super(context, name, factory, version);}public DatabaseHelper(Context context, String name,int version) {this(context, name, null, version);}public DatabaseHelper(Context context, String name) {this(context, name, VERSION);}@Overridepublic void onCreate(SQLiteDatabase db) {System.out.println("create table is invoked !!!");db.execSQL("create table sharp(id integer primary key autoincrement, username varchar(255))");}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {System.out.println("update table is invoked !!!");}}