Difference between revisions of "OOP Class9"

Latest revision as of 16:31, 10 June 2019

PolyMorphism

Using the least specific class to increase reuse.

Value vs Reference Types

int, float, string and most built in types are value types

defined classes are Reference types.

Review Coins

?'s

Review MotorVehicle

?'s

Motorvehicle Diagram

Oop Motorvehicle Diagram

http://iam.colum.edu/oop/browser/browser.aspx?f=/classsource/class7/MotorvehicleRace

Private instance data members - accessors

Microsoft has stared calling private variables with accessors Properties

Private class memebers the use get and set keyword to set and retrieve data. Get and set are known as accessor methods private members are helpful when you want to also do other things when a data member is changed or change the rutern value under certain conditions. C# Programmer's Reference - Accessors http://msdn.microsoft.com/library/default.asp?url=/library/en-us/csref/html/vclrfaccessorspg.asp. Lastly accessor also make read only and write only variables possible

//private string color read/write
private string color;

public string Color
{
  get
  {
   return color;
  }
  set
  {
   color = value;
  }
}

//private string color read only
private string color;

public string Color
{
  get
  {
   return color;
  }
}

Another property that is a good candidate for a private instance data member is the dogs age

private string age;

public int Age
{
  //age can only be accessed with get there is no set accessor
  //age must be set with HappyBirthday()
  get
  {
   return age;
  }
}

public int HappyBirthday()
{
  age++;
  return age;
}

Windows forms

Separation of Concern

https://en.wikipedia.org/wiki/Separation_of_concerns

Keep you Moodle Object (logic) classes and your UI Presentation classes separate. This will probably be very different from how you handled login in form in previous classes. We will try to keep all the Model login in the Model classes and UI Logic in the Form class. This will allow us to easily move the Model classes to a different UI like the Web or XAML.

Events

events from a windows form or web page are handled by event handlers. Events are raised when a user interacts with interface elements and handled by the event handlers.

http://www.csharphelp.com/archives/archive253.html

Examaple of event handlers and classes

http://iam.colum.edu/oop/MotorvehicleRace.zip

private void button1_Click(object sender, EventArgs e)
        {
            Console.WriteLine("button1 Clicked");
            MessageBox.Show("button1 Clicked");   
        }

Create a windows form with a button the uses your class.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsDog
{
    public partial class Form1 : Form
    {
        Dog fido;  //The form 'has a' dog
        
        public Form1()
        {
            InitializeComponent();
            fido = new Dog();
        }

        private void btnBark_Click(object sender, EventArgs e)
        {
            lblBark.Text = fido.Bark(); //UIEvents are delegated to the model class
        }


        
}

XAML Example

Timer in XAML https://msdn.microsoft.com/en-us/library/cc189084(v=vs.95).aspx

Home Work

Create a windows form and port your classes. The form should have UI elements (buttons, dropdown, etc) that demonstrate the use of you classes.

Get Android Studio Installed

You wili need

• Java JDK http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1880260.html I'm still using Java 7 Java 8 also should ve fine
• Android Studio http://developer.android.com/sdk/installing/index.html?pkg=studio

Watch the Android-Studio-First-Look https://www.lynda.com/Android-tutorials/Welcome/143103/168098-4.html

You should logon to Oasis http://oasis.colum.edu First then select the training tab. Then search for 'Android-Studio-First-Look'

• Section 0 Introduction
• Section 1 Getting Started
• Section 2 Exploring the User Interface (fine to watch next week)
• Section 3 Designing and Coding (fine to watch next week)

https://www.lynda.com/Android-tutorials/Welcome/143103/168098-4.html