DatabaseHelper.java

package com.example.emanuel.aluno;

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

public class DatabaseHelper extends SQLiteOpenHelper {

    private static final int VERSION = 1;
    private static final String DBNAME  = "alunos";

    public DatabaseHelper(Context context) {
        super(context, DBNAME, null, VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE " + StudentsEntry.TABLE_NAME +
                " ( " + StudentsEntry._ID + " INTERGER PRIMARY KEY AUTOINCREMENT , "
                + StudentsEntry.COLUNM_NAME_NAME + " VARCHAR(255) , "
                + StudentsEntry.COLUNM_NAME_MAT + " VARCHAR(255)) ");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

    public static class StudentsEntry implements BaseColumns {
        public static final String TABLE_NAME = "students";
        public static final String COLUNM_NAME_NAME = "name";
        public static final String COLUNM_NAME_MAT = "mat";
    }

}

MainActivity.java

package com.example.emanuel.aluno;

import android.database.Cursor;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.SimpleCursorAdapter;

public class MainActivity extends AppCompatActivity {

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

        Button btnSave = (Button) findViewById(R.id.btnSave);

        btnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                StudentsTable studentsTable = new StudentsTable(getApplicationContext());
                String name = ((EditText)findViewById(R.id.editName)).getText().toString();
                String matricula = ((EditText)findViewById(R.id.editMat)).getText().toString();

                studentsTable.save(name,matricula);

                ListView studentsListView = (ListView) findViewById(R.id.studentsList);
                ((SimpleCursorAdapter)studentsListView.getAdapter()).changeCursor(studentsTable.list());
            }
        });

        ListView studentsList = (ListView) findViewById(R.id.studentsList);
        StudentsTable studentsTable = new StudentsTable(getApplicationContext());

        Cursor cursor = studentsTable.list();

        SimpleCursorAdapter simpleCursorAdapter = new SimpleCursorAdapter(
                this, android.R.layout.simple_expandable_list_item_2, cursor, new String[]{
                DatabaseHelper.StudentsEntry.COLUNM_NAME_NAME,
                DatabaseHelper.StudentsEntry.COLUNM_NAME_MAT
            }, new int[] { android.R.id.text1, android.R.id.text2 }
        );

        studentsList.setAdapter(simpleCursorAdapter);
    }
}

StudentsTable.java

package com.example.emanuel.aluno;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;

public class StudentsTable {

    DatabaseHelper dbHelper;

    public StudentsTable(Context context){
        dbHelper = new DatabaseHelper(context);
    }

    public void save(String name, String matricula){
        SQLiteDatabase db = dbHelper.getWritableDatabase();

        ContentValues contentValues = new ContentValues();
        contentValues.put(DatabaseHelper.StudentsEntry.COLUNM_NAME_NAME, name);
        contentValues.put(DatabaseHelper.StudentsEntry.COLUNM_NAME_MAT, matricula);

        long ret = db.insert(DatabaseHelper.StudentsEntry.TABLE_NAME, null, contentValues);

        if(ret == -1){
            throw new SQLiteException("erro");
        }
        db.close();
    }

    public Cursor list(){
        SQLiteDatabase db = dbHelper.getReadableDatabase();
        Cursor query = db.query(DatabaseHelper.StudentsEntry.TABLE_NAME, new String[]{
                        DatabaseHelper.StudentsEntry._ID,
                        DatabaseHelper.StudentsEntry.COLUNM_NAME_NAME,
                        DatabaseHelper.StudentsEntry.COLUNM_NAME_NAME
                }, null, null, null, null, null);
        query.moveToFirst();
        db.close();
        return query;
    }

}