使用SQLiteOpenHelper插入数据到数据库并读取数据库中的内容

来源：互联网发布：wps两个表格数据对比编辑：程序博客网时间：2024/05/22 06:36

1、首先新建一个类DBOpenHelper继承SQLiteOpenHelper然后重写其方法。

类DBOpenHelper

package org.mobiletrain.sqlite_demo4;import android.annotation.SuppressLint;import android.content.ContentValues;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;public class DBOpenHelper extends SQLiteOpenHelper{String sql = "create table if not exists stutb(_id integer primary key autoincrement," +"name text not null,sex text not null,age integer not null)";@SuppressLint("NewApi")public DBOpenHelper(Context context, String name, CursorFactory factory,int version) {super(context, name, factory, version);// TODO Auto-generated constructor stub}public DBOpenHelper(Context context, String name) {super(context, name, null, 1);}//首次创建数据库的时候调用，我们一般把建库或者建表的方法放在其中@Override  public void onCreate(SQLiteDatabase db) {// TODO Auto-generated method stubdb.execSQL(sql);db.execSQL("insert into stutb(name,sex,age)values('张三','女',22)");ContentValues values = new ContentValues();values.put("name", "王小明");values.put("sex", "男");values.put("age", 25);db.insert("stutb", null, values);values.clear();}//数据库的版本发生变化的时候，会自动执行。@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {// TODO Auto-generated method stubif (newVersion>oldVersion) {//执行版本更新后的逻辑操作}}}

MainActivity：

package org.mobiletrain.sqlite_demo4;import android.os.Bundle;import android.app.Activity;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.util.Log;import android.view.Menu;public class MainActivity extends Activity {DBOpenHelper helper;SQLiteDatabase db;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);helper = new DBOpenHelper(this, "stu.db"); db = helper.getWritableDatabase();Cursor cursor = db.rawQuery("select * from stutb", null);if (cursor!=null) {String columns[] = cursor.getColumnNames();while (cursor.moveToNext()) {for (String columnName:columns) {Log.i("main", columnName+":"+cursor.getString(cursor.getColumnIndex(columnName)));}}cursor.close();}db.close();}}

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