Android的Sqlite练习

1，xml布局

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:visibility="visible">


    <TextView
        android:id="@+id/tv1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="100dp"
        android:text="姓名"
        android:textSize="28dp" />
    <TextView
        android:id="@+id/tv2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="150dp"
        android:text="年龄"
        android:textSize="28dp" />
    <EditText
        android:id="@+id/etname"
        android:layout_width="289dp"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:layout_toRightOf="@+id/tv1"
        android:layout_marginTop="100dp"/>
    <EditText
        android:id="@+id/eteag"
        android:layout_width="289dp"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:layout_toRightOf="@+id/tv2"
        android:layout_marginTop="150dp"
        />

    <Button
        android:id="@+id/bt1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="确定"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="500dp"
        android:onClick="onClick"

        />


</RelativeLayout>

　　2，方法

package com.example.myappsqlite;

import androidx.annotation.Nullable;
import androidx.annotation.StringDef;
import androidx.appcompat.app.AppCompatActivity;

import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    String name;
    String eag;
    private EditText et,et2;
    private Button bt;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        et = (EditText) findViewById(R.id.etname);
        et2 = (EditText)findViewById(R.id.eteag);
        bt = (Button) findViewById(R.id.bt1);

    }

    public void onClick(View v){
        SQLiteDatabase db;
        ContentValues values;
        name = et.getText().toString();
        eag = et2.getText().toString();
        MyHelper myhelper = new MyHelper(this);
        db =myhelper.getWritableDatabase();
        values = new ContentValues();
        values.put("name",name);
        values.put("eag",eag);
        long id = db.insert("stu",null,values);
        db.close();
        Toast.makeText(MainActivity.this,"插入成功",Toast.LENGTH_SHORT).show();

    }
}

class MyHelper extends SQLiteOpenHelper{

    public MyHelper(@Nullable Context context) {
        super(context,"student.db", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE stu(id integer primary key autoincrement ,name varchar(5),eag varchar(3))");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int i, int i1) {
    }
}