<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="16dp" >


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="130dp" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="姓 名 ："
            android:textSize="18sp" />

        <EditText
            android:id="@+id/et_name"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="请输入姓名"
            android:textSize="16sp" />
    </LinearLayout>


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="年 龄："
            android:textSize="18sp" />

        <EditText
            android:id="@+id/et_age"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="输入年龄"
            android:textSize="16sp" />
    </LinearLayout>


    <Button
        android:id="@+id/btn_add"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/et_age"
        android:layout_marginRight="2dp"
        android:background="#B9B9FF"
        android:onClick="add"
        android:text="注册"
        android:textSize="18sp" />

    <TextView
        android:id="@+id/tv_show"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="25dp"
        android:textSize="20sp" />

</LinearLayout>

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }

    public void add(View v) {
        StuOpenHelper helper = new StuOpenHelper(this);
        SQLiteDatabase db = helper.getWritableDatabase();
        String name = ((EditText) findViewById(R.id.et_name)).getText()
                .toString();
        int age = Integer.parseInt(((EditText) findViewById(R.id.et_age))
                .getText().toString());

        db.execSQL("insert into stuinfo (name,age) values(?,?)", new Object[]{
                name, age});
        Toast.makeText(this, "注册成功", Toast.LENGTH_SHORT).show();

    }
}

package com.example.myapplication;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;



public class StuOpenHelper extends SQLiteOpenHelper {

    public StuOpenHelper(Context context) {
        super(context, "student.db", null, 2);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table stuinfo(_id integer primary key autoincrement,name varchar(20),age integer)");
        db.execSQL("create table class(_id integer primary key autoincrement,classname varchar(20))");
    }

    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
        System.out.println("版本更新,老版本是"+ i+"新版本是"+i1);

    }
}