user interfaces - lecture 16 model - view - controller · 2018. 9. 6. · and nswindowcontroller i...

User Interfaces

Lecture 16

Model - View - Controller

Hamza [email protected]

September 6, 2018

Last Lecture Summary

I Default Cocoa application.I NSApplicationI NSApplicationDelegateI XIB/NIB-file storing the visual elementsI RunLoop-event loop class, useful for running timersI Outlet, target and action mechanism.I @IBOutlet-annotationI @IBAction-annotationI Any questions ???

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Hamza Bennani -*- COSC346 -*- Model - View - Controller -*- September 6, 2018

MVC

DefinitionI Introduced in the late 70’s in SmalltalkI Prevalent in many frameworks:

I Web developmentI Cocoa

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MVC in ApplicationsGenerally, applications perform the following functions:

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MVC in Cocoa

I AppKit: classes that provide the view and controllerfunctionality

I Core Data: model that abstracts away details of archiving(In this paper we will be almost always creating our ownmodels)

I Foundation: classes that glue and customise all thecomponents together

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MVC in Cocoa ExampleUser interacts with a slider

1. Slider sends a msg to the controller with the new value2. The controller notifies the model about the value change3. The model updates the corresponding value

I Constraints checked, Update, Notification4. Controller notifies the view that the model has changed

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AppKitMVC

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AppKitMVC

I NSResponder: handling of mouse and keyboard eventsAbstract class

I NSView: rectangle responsible for rendering visualinformation

I Subclass of NSResponderI Abstract class: you either customise by extending it, or use

one of predefined subclasses, such as: NSTabView,NSSplitView, NSScrollView, etc.

I NSControl: sending actions when user interacts with thecontrol

I Don’t confuse with a ControllerI Subclass of NSViewI Abstract class: you either customise by extending it, or use

one of predefined subclasses, such as: NSButton,NSSlider, NSScroller, etc.

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AppKitMVC

I Bindings controllers:I NSController, NSObjectController, NSArrayController,

NSUserDefaultsController, and NSTreeControllerI These are special classes that use Cocoa’s bindings and

key value encoding technology, allowing connection andbinding data between view and model elements throughInterface Builder - no code necessary

I These objects implement common logic for mediatingbetween the model and the view

I Application behaviour:I NSDocument, NSDocumentController, NSViewController,

and NSWindowControllerI These control the fundamental aspects of a GUI

application, such as multiple windows, views anddocuments

I Your custom controller: Typically, your application delegate10


Core DataMVC

I Collection of classes that abstract away the details of howdata is stored and manipulatedYou work with entities (a little bit like a class), attributes(like instance variables in a class), and relationships

I Possible to bind data to controllers in the Interface Builderwithout needing code

I For persistent storage can store data as XML, binaryformat, or in an SQLite database

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Summary

I Model-View-Controller pattern underlines the design ofCocoa framework.

I View: code that deals with the visual presentation side ofthe program Tends to change often

I Model: code that implements the underlyingrepresentation that stores the information/content Tends toremain unchanged

I Controller: the code logic that connects the View andModel components

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TimerApp

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TimerApp MVC

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user interfaces - lecture 16 model - view - controller · 2018. 9. 6. · and nswindowcontroller i...

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