Android创建SQLite数据库及增删改查

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

public class MyDBHelper extends SQLiteOpenHelper {
    private Context context;
    public MyDBHelper(Context context,String name,int version){
        super(context,name,null,version);
        this.context = context;
    }
    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        String sql = "create table person(_id integer primary key autoincrement," +
                "name varchar,age int)";
        sqLiteDatabase.execSQL(sql);
        sqLiteDatabase.execSQL("insert into person(name,age) values('Tom',18)");
        sqLiteDatabase.execSQL("insert into person(name,age) values('Jack',19)");
        sqLiteDatabase.execSQL("insert into person(name,age) values('Thomas',20)");
        sqLiteDatabase.execSQL("insert into person(name,age) values('arry',20)");
        Toast.makeText(context, "MyDBHelper on Create()", Toast.LENGTH_SHORT).show();



    }

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

    }
}

import androidx.appcompat.app.AppCompatActivity;

import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

import database.MyDBHelper;

public class DBDemoActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_d_b_demo);
    }
    /*
    * 创建数据库*/
    public void createDB(View view){
        MyDBHelper myDBHelper = new MyDBHelper(this,"mydb.db",1);
        SQLiteDatabase database = myDBHelper.getReadableDatabase();

    }
    //增加数据
    public void insertData(View view){
        MyDBHelper myDBHelper = new MyDBHelper(this,"mydb.db",1);
        SQLiteDatabase database = myDBHelper.getReadableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put("name","汪峰");
        contentValues.put("age",30);
        long id = database.insert("preson",null,contentValues);
        database.close();
        Toast.makeText(this, "id"+id, Toast.LENGTH_SHORT).show();
    }
    //修改数据
    public void updateData(View view){
        MyDBHelper myDBHelper = new MyDBHelper(this,"mydb.db",1);
        SQLiteDatabase database = myDBHelper.getReadableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put("name","韩红");
        contentValues.put("age",35);
        int rows = database.update("person",contentValues,"name = ?",new String[]{"Tom"});
        database.close();
        Toast.makeText(this, "rows"+rows, Toast.LENGTH_SHORT).show();
    }
    //删除数据
    public void deleteData(View view){
        MyDBHelper myDBHelper = new MyDBHelper(this,"mydb.db",1);
        SQLiteDatabase database = myDBHelper.getReadableDatabase();
        int row = database.delete("person","_id = ?",new String[]{"2"});
        database.close();
        Toast.makeText(this, "rows"+row, Toast.LENGTH_SHORT).show();
    }
    //查询数据
    public void queryData(View view){
        MyDBHelper myDBHelper = new MyDBHelper(this,"mydb.db",1);
        SQLiteDatabase database = myDBHelper.getReadableDatabase();
        Cursor cursor = database.query("person",null,
                null,null,null,
                null,null);
        if (cursor.moveToFirst()){
            do {
                String name = cursor.getString(cursor.getColumnIndex("name"));
                int age = cursor.getInt(cursor.getColumnIndex("age"));
                Log.d("TAG",name + ":" + age);
            }while (cursor.moveToNext());
        }
        database.close();//关闭数据库

    }


}

布局文件

    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".DBDemoActivity">

    <Button
        android:id="@+id/btn_db_createdb"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="createDB"
        android:text="创建数据库"/>
    <Button
        android:id="@+id/btn_db_insert"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="insertData"
        android:text="插入记录"/>
    <Button
        android:id="@+id/btn_db_delete"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="deleteData"
        android:text="删除记录"/>
    <Button
        android:id="@+id/btn_db_updata"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="updateData"
        android:text="修改记录"/>
    <Button
        android:id="@+id/btn_db_query"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="queryData"
        android:text="查询记录"/>
</LinearLayout>