DatabaseHelper.java

//Nayan Pasari
//ID: 111868106
package com.example.hackmatcher;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHelper extends SQLiteOpenHelper {

    public static final String DATABASE_NAME = "register.db";

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, 1);
    }

    /*
    onCreate: Creates a table
     */
    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("Create table user(username text primary key,password text)");
    }

    /*
    onUpgrade: This will be used when there's any changes to the version.
     */
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL(" drop table if exists user");
    }

    /*
    Inserts all the values to the table or content values
     */
    public boolean insert(String username, String password) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put("username",username);
        contentValues.put("password",password);
        long res = db.insert("user", null, contentValues);
        if (res == -1) {
            return false;
        } else {
            return true;
        }
    }

    /*
    Checks or reads from the table if there's a valid username.
     */
    public boolean checkUser(String username) {
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery("Select * from user where username=?", new String[]{username});
        if (cursor.getCount() > 0) {
            return false;
        } else {
            return true;
        }
    }

    /*
    Checks or reads from the table if there's a valid username and password.
     */
    public boolean checkUserPass(String username, String password) {
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery("Select * from user where username=? and password=?", new String[]{username, password});
        if (cursor.getCount() > 0) {
            return true;
        } else {
            return false;
        }
    }
}