Android--数据库操作辅助类：SQLiteOpenHelper

1.MyDatabaseHelper.java代码如下：

package org.lxh.demo;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;public class MyDatabaseHelper extends SQLiteOpenHelper {private static final String DATABASENAME = "test.db";private static final int DATABASEVERSION = 1;private static final String TABLENAME = "mytab";public MyDatabaseHelper(Context context) {super(context, DATABASENAME, null, DATABASEVERSION);}@Overridepublic void onCreate(SQLiteDatabase db) {/* * String sql="CREATE TABLE"+TABLENAME+"("+ * "id    INTEGER    PRIMARY KEY,"+ "name   VARCHAR(50)  NOT NULL,"+ * "birthday   DATE   NOT NULL)"; */String sql = "CREATE TABLE " + TABLENAME+ "("+ "idINTEGERPRIMARY 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}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {String sql = "DROP TABLE IF EXISTS" + TABLENAME;db.execSQL(sql);this.onCreate(db);}}

2.Hello.java代码如下：

package org.lxh.demo;import android.app.Activity;import android.app.AlertDialog;import android.app.Dialog;import android.content.DialogInterface;import android.database.sqlite.SQLiteOpenHelper;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.view.View.OnFocusChangeListener;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;public class Hello extends Activity {public void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState); // 生命周期方法super.setContentView(R.layout.main); // 设置要使用的布局管理器SQLiteOpenHelper helper=new MyDatabaseHelper(this);helper.getWritableDatabase();}}

运行后如下：

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